Virtualization


OpenShift Container Platform 4.17

OpenShift Virtualization installation, usage, and release notes

Red Hat OpenShift Documentation Team

Abstract

This document provides information about how to use OpenShift Virtualization in OpenShift Container Platform.

Chapter 1. About

1.1. About OpenShift Virtualization

Learn about OpenShift Virtualization’s capabilities and support scope.

1.1.1. What you can do with OpenShift Virtualization

OpenShift Virtualization is an add-on to OpenShift Container Platform that allows you to run and manage virtual machine workloads alongside container workloads.

OpenShift Virtualization adds new objects into your OpenShift Container Platform cluster by using Kubernetes custom resources to enable virtualization tasks. These tasks include:

  • Creating and managing Linux and Windows virtual machines (VMs)
  • Running pod and VM workloads alongside each other in a cluster
  • Connecting to virtual machines through a variety of consoles and CLI tools
  • Importing and cloning existing virtual machines
  • Managing network interface controllers and storage disks attached to virtual machines
  • Live migrating virtual machines between nodes

An enhanced web console provides a graphical portal to manage these virtualized resources alongside the OpenShift Container Platform cluster containers and infrastructure.

OpenShift Virtualization is designed and tested to work well with Red Hat OpenShift Data Foundation features.

Important

When you deploy OpenShift Virtualization with OpenShift Data Foundation, you must create a dedicated storage class for Windows virtual machine disks. See Optimizing ODF PersistentVolumes for Windows VMs for details.

You can use OpenShift Virtualization with OVN-Kubernetes or one of the other certified network plugins listed in Certified OpenShift CNI Plug-ins.

You can check your OpenShift Virtualization cluster for compliance issues by installing the Compliance Operator and running a scan with the ocp4-moderate and ocp4-moderate-node profiles. The Compliance Operator uses OpenSCAP, a NIST-certified tool, to scan and enforce security policies.

1.1.1.1. OpenShift Virtualization supported cluster version

OpenShift Virtualization 4.17 is supported for use on OpenShift Container Platform 4.17 clusters. To use the latest z-stream release of OpenShift Virtualization, you must first upgrade to the latest version of OpenShift Container Platform.

1.1.2. About volume and access modes for virtual machine disks

If you use the storage API with known storage providers, the volume and access modes are selected automatically. However, if you use a storage class that does not have a storage profile, you must configure the volume and access mode.

For best results, use the ReadWriteMany (RWX) access mode and the Block volume mode. This is important for the following reasons:

  • ReadWriteMany (RWX) access mode is required for live migration.
  • The Block volume mode performs significantly better than the Filesystem volume mode. This is because the Filesystem volume mode uses more storage layers, including a file system layer and a disk image file. These layers are not necessary for VM disk storage.

    For example, if you use Red Hat OpenShift Data Foundation, Ceph RBD volumes are preferable to CephFS volumes.

Important

You cannot live migrate virtual machines with the following configurations:

  • Storage volume with ReadWriteOnce (RWO) access mode
  • Passthrough features such as GPUs

Set the evictionStrategy field to None for these virtual machines. The None strategy powers down VMs during node reboots.

1.1.3. Single-node OpenShift differences

You can install OpenShift Virtualization on single-node OpenShift.

However, you should be aware that Single-node OpenShift does not support the following features:

  • High availability
  • Pod disruption
  • Live migration
  • Virtual machines or templates that have an eviction strategy configured

1.1.4. Additional resources

1.2. Security policies

Learn about OpenShift Virtualization security and authorization.

Key points

  • OpenShift Virtualization adheres to the restricted Kubernetes pod security standards profile, which aims to enforce the current best practices for pod security.
  • Virtual machine (VM) workloads run as unprivileged pods.
  • Security context constraints (SCCs) are defined for the kubevirt-controller service account.
  • TLS certificates for OpenShift Virtualization components are renewed and rotated automatically.

1.2.1. About workload security

By default, virtual machine (VM) workloads do not run with root privileges in OpenShift Virtualization, and there are no supported OpenShift Virtualization features that require root privileges.

For each VM, a virt-launcher pod runs an instance of libvirt in session mode to manage the VM process. In session mode, the libvirt daemon runs as a non-root user account and only permits connections from clients that are running under the same user identifier (UID). Therefore, VMs run as unprivileged pods, adhering to the security principle of least privilege.

1.2.2. TLS certificates

TLS certificates for OpenShift Virtualization components are renewed and rotated automatically. You are not required to refresh them manually.

Automatic renewal schedules

TLS certificates are automatically deleted and replaced according to the following schedule:

  • KubeVirt certificates are renewed daily.
  • Containerized Data Importer controller (CDI) certificates are renewed every 15 days.
  • MAC pool certificates are renewed every year.

Automatic TLS certificate rotation does not disrupt any operations. For example, the following operations continue to function without any disruption:

  • Migrations
  • Image uploads
  • VNC and console connections

1.2.3. Authorization

OpenShift Virtualization uses role-based access control (RBAC) to define permissions for human users and service accounts. The permissions defined for service accounts control the actions that OpenShift Virtualization components can perform.

You can also use RBAC roles to manage user access to virtualization features. For example, an administrator can create an RBAC role that provides the permissions required to launch a virtual machine. The administrator can then restrict access by binding the role to specific users.

1.2.3.1. Default cluster roles for OpenShift Virtualization

By using cluster role aggregation, OpenShift Virtualization extends the default OpenShift Container Platform cluster roles to include permissions for accessing virtualization objects.

Table 1.1. OpenShift Virtualization cluster roles
Default cluster roleOpenShift Virtualization cluster roleOpenShift Virtualization cluster role description

view

kubevirt.io:view

A user that can view all OpenShift Virtualization resources in the cluster but cannot create, delete, modify, or access them. For example, the user can see that a virtual machine (VM) is running but cannot shut it down or gain access to its console.

edit

kubevirt.io:edit

A user that can modify all OpenShift Virtualization resources in the cluster. For example, the user can create VMs, access VM consoles, and delete VMs.

admin

kubevirt.io:admin

A user that has full permissions to all OpenShift Virtualization resources, including the ability to delete collections of resources. The user can also view and modify the OpenShift Virtualization runtime configuration, which is located in the HyperConverged custom resource in the openshift-cnv namespace.

1.2.3.2. RBAC roles for storage features in OpenShift Virtualization

The following permissions are granted to the Containerized Data Importer (CDI), including the cdi-operator and cdi-controller service accounts.

1.2.3.2.1. Cluster-wide RBAC roles
Table 1.2. Aggregated cluster roles for the cdi.kubevirt.io API group
CDI cluster roleResourcesVerbs

cdi.kubevirt.io:admin

datavolumes, uploadtokenrequests

* (all)

datavolumes/source

create

cdi.kubevirt.io:edit

datavolumes, uploadtokenrequests

*

datavolumes/source

create

cdi.kubevirt.io:view

cdiconfigs, dataimportcrons, datasources, datavolumes, objecttransfers, storageprofiles, volumeimportsources, volumeuploadsources, volumeclonesources

get, list, watch

datavolumes/source

create

cdi.kubevirt.io:config-reader

cdiconfigs, storageprofiles

get, list, watch

Table 1.3. Cluster-wide roles for the cdi-operator service account
API groupResourcesVerbs

rbac.authorization.k8s.io

clusterrolebindings, clusterroles

get, list, watch, create, update, delete

security.openshift.io

securitycontextconstraints

get, list, watch, update, create

apiextensions.k8s.io

customresourcedefinitions, customresourcedefinitions/status

get, list, watch, create, update, delete

cdi.kubevirt.io

*

*

upload.cdi.kubevirt.io

*

*

admissionregistration.k8s.io

validatingwebhookconfigurations, mutatingwebhookconfigurations

create, list, watch

admissionregistration.k8s.io

validatingwebhookconfigurations

Allow list: cdi-api-dataimportcron-validate, cdi-api-populator-validate, cdi-api-datavolume-validate, cdi-api-validate, objecttransfer-api-validate

get, update, delete

admissionregistration.k8s.io

mutatingwebhookconfigurations

Allow list: cdi-api-datavolume-mutate

get, update, delete

apiregistration.k8s.io

apiservices

get, list, watch, create, update, delete

Table 1.4. Cluster-wide roles for the cdi-controller service account
API groupResourcesVerbs

"" (core)

events

create, patch

"" (core)

persistentvolumeclaims

get, list, watch, create, update, delete, deletecollection, patch

"" (core)

persistentvolumes

get, list, watch, update

"" (core)

persistentvolumeclaims/finalizers, pods/finalizers

update

"" (core)

pods, services

get, list, watch, create, delete

"" (core)

configmaps

get, create

storage.k8s.io

storageclasses, csidrivers

get, list, watch

config.openshift.io

proxies

get, list, watch

cdi.kubevirt.io

*

*

snapshot.storage.k8s.io

volumesnapshots, volumesnapshotclasses, volumesnapshotcontents

get, list, watch, create, delete

snapshot.storage.k8s.io

volumesnapshots

update, deletecollection

apiextensions.k8s.io

customresourcedefinitions

get, list, watch

scheduling.k8s.io

priorityclasses

get, list, watch

image.openshift.io

imagestreams

get, list, watch

"" (core)

secrets

create

kubevirt.io

virtualmachines/finalizers

update

1.2.3.2.2. Namespaced RBAC roles
Table 1.5. Namespaced roles for the cdi-operator service account
API groupResourcesVerbs

rbac.authorization.k8s.io

rolebindings, roles

get, list, watch, create, update, delete

"" (core)

serviceaccounts, configmaps, events, secrets, services

get, list, watch, create, update, patch, delete

apps

deployments, deployments/finalizers

get, list, watch, create, update, delete

route.openshift.io

routes, routes/custom-host

get, list, watch, create, update

config.openshift.io

proxies

get, list, watch

monitoring.coreos.com

servicemonitors, prometheusrules

get, list, watch, create, delete, update, patch

coordination.k8s.io

leases

get, create, update

Table 1.6. Namespaced roles for the cdi-controller service account
API groupResourcesVerbs

"" (core)

configmaps

get, list, watch, create, update, delete

"" (core)

secrets

get, list, watch

batch

cronjobs

get, list, watch, create, update, delete

batch

jobs

create, delete, list, watch

coordination.k8s.io

leases

get, create, update

networking.k8s.io

ingresses

get, list, watch

route.openshift.io

routes

get, list, watch

1.2.3.3. Additional SCCs and permissions for the kubevirt-controller service account

Security context constraints (SCCs) control permissions for pods. These permissions include actions that a pod, a collection of containers, can perform and what resources it can access. You can use SCCs to define a set of conditions that a pod must run with to be accepted into the system.

The virt-controller is a cluster controller that creates the virt-launcher pods for virtual machines in the cluster. These pods are granted permissions by the kubevirt-controller service account.

The kubevirt-controller service account is granted additional SCCs and Linux capabilities so that it can create virt-launcher pods with the appropriate permissions. These extended permissions allow virtual machines to use OpenShift Virtualization features that are beyond the scope of typical pods.

The kubevirt-controller service account is granted the following SCCs:

  • scc.AllowHostDirVolumePlugin = true
    This allows virtual machines to use the hostpath volume plugin.
  • scc.AllowPrivilegedContainer = false
    This ensures the virt-launcher pod is not run as a privileged container.
  • scc.AllowedCapabilities = []corev1.Capability{"SYS_NICE", "NET_BIND_SERVICE"}

    • SYS_NICE allows setting the CPU affinity.
    • NET_BIND_SERVICE allows DHCP and Slirp operations.

Viewing the SCC and RBAC definitions for the kubevirt-controller

You can view the SecurityContextConstraints definition for the kubevirt-controller by using the oc tool:

$ oc get scc kubevirt-controller -o yaml

You can view the RBAC definition for the kubevirt-controller clusterrole by using the oc tool:

$ oc get clusterrole kubevirt-controller -o yaml

1.2.4. Additional resources

1.3. OpenShift Virtualization Architecture

The Operator Lifecycle Manager (OLM) deploys operator pods for each component of OpenShift Virtualization:

  • Compute: virt-operator
  • Storage: cdi-operator
  • Network: cluster-network-addons-operator
  • Scaling: ssp-operator

OLM also deploys the hyperconverged-cluster-operator pod, which is responsible for the deployment, configuration, and life cycle of other components, and several helper pods: hco-webhook, and hyperconverged-cluster-cli-download.

After all operator pods are successfully deployed, you should create the HyperConverged custom resource (CR). The configurations set in the HyperConverged CR serve as the single source of truth and the entrypoint for OpenShift Virtualization, and guide the behavior of the CRs.

The HyperConverged CR creates corresponding CRs for the operators of all other components within its reconciliation loop. Each operator then creates resources such as daemon sets, config maps, and additional components for the OpenShift Virtualization control plane. For example, when the HyperConverged Operator (HCO) creates the KubeVirt CR, the OpenShift Virtualization Operator reconciles it and creates additional resources such as virt-controller, virt-handler, and virt-api.

The OLM deploys the Hostpath Provisioner (HPP) Operator, but it is not functional until you create a hostpath-provisioner CR.

Deployments

1.3.1. About the HyperConverged Operator (HCO)

The HCO, hco-operator, provides a single entry point for deploying and managing OpenShift Virtualization and several helper operators with opinionated defaults. It also creates custom resources (CRs) for those operators.

hco-operator components
Table 1.7. HyperConverged Operator components
ComponentDescription

deployment/hco-webhook

Validates the HyperConverged custom resource contents.

deployment/hyperconverged-cluster-cli-download

Provides the virtctl tool binaries to the cluster so that you can download them directly from the cluster.

KubeVirt/kubevirt-kubevirt-hyperconverged

Contains all operators, CRs, and objects needed by OpenShift Virtualization.

SSP/ssp-kubevirt-hyperconverged

A Scheduling, Scale, and Performance (SSP) CR. This is automatically created by the HCO.

CDI/cdi-kubevirt-hyperconverged

A Containerized Data Importer (CDI) CR. This is automatically created by the HCO.

NetworkAddonsConfig/cluster

A CR that instructs and is managed by the cluster-network-addons-operator.

1.3.2. About the Containerized Data Importer (CDI) Operator

The CDI Operator, cdi-operator, manages CDI and its related resources, which imports a virtual machine (VM) image into a persistent volume claim (PVC) by using a data volume.

cdi-operator components
Table 1.8. CDI Operator components
ComponentDescription

deployment/cdi-apiserver

Manages the authorization to upload VM disks into PVCs by issuing secure upload tokens.

deployment/cdi-uploadproxy

Directs external disk upload traffic to the appropriate upload server pod so that it can be written to the correct PVC. Requires a valid upload token.

pod/cdi-importer

Helper pod that imports a virtual machine image into a PVC when creating a data volume.

1.3.3. About the Cluster Network Addons Operator

The Cluster Network Addons Operator, cluster-network-addons-operator, deploys networking components on a cluster and manages the related resources for extended network functionality.

cluster-network-addons-operator components
Table 1.9. Cluster Network Addons Operator components
ComponentDescription

deployment/kubemacpool-cert-manager

Manages TLS certificates of Kubemacpool’s webhooks.

deployment/kubemacpool-mac-controller-manager

Provides a MAC address pooling service for virtual machine (VM) network interface cards (NICs).

daemonset/bridge-marker

Marks network bridges available on nodes as node resources.

daemonset/kube-cni-linux-bridge-plugin

Installs Container Network Interface (CNI) plugins on cluster nodes, enabling the attachment of VMs to Linux bridges through network attachment definitions.

1.3.4. About the Hostpath Provisioner (HPP) Operator

The HPP Operator, hostpath-provisioner-operator, deploys and manages the multi-node HPP and related resources.

hpp-operator components
Table 1.10. HPP Operator components
ComponentDescription

deployment/hpp-pool-hpp-csi-pvc-block-<worker_node_name>

Provides a worker for each node where the HPP is designated to run. The pods mount the specified backing storage on the node.

daemonset/hostpath-provisioner-csi

Implements the Container Storage Interface (CSI) driver interface of the HPP.

daemonset/hostpath-provisioner

Implements the legacy driver interface of the HPP.

1.3.5. About the Scheduling, Scale, and Performance (SSP) Operator

The SSP Operator, ssp-operator, deploys the common templates, the related default boot sources, the pipeline tasks, and the template validator.

1.3.6. About the OpenShift Virtualization Operator

The OpenShift Virtualization Operator, virt-operator, deploys, upgrades, and manages OpenShift Virtualization without disrupting current virtual machine (VM) workloads. In addition, the OpenShift Virtualization Operator deploys the common instance types and common preferences.

virt-operator components
Table 1.11. virt-operator components
ComponentDescription

deployment/virt-api

HTTP API server that serves as the entry point for all virtualization-related flows.

deployment/virt-controller

Observes the creation of a new VM instance object and creates a corresponding pod. When the pod is scheduled on a node, virt-controller updates the VM with the node name.

daemonset/virt-handler

Monitors any changes to a VM and instructs virt-launcher to perform the required operations. This component is node-specific.

pod/virt-launcher

Contains the VM that was created by the user as implemented by libvirt and qemu.

Chapter 2. Release notes

2.1. OpenShift Virtualization release notes

2.1.1. Providing documentation feedback

To report an error or to improve our documentation, log in to your Red Hat Jira account and submit a Jira issue.

2.1.2. About Red Hat OpenShift Virtualization

With Red Hat OpenShift Virtualization, you can bring traditional virtual machines (VMs) into OpenShift Container Platform and run them alongside containers. In OpenShift Virtualization, VMs are native Kubernetes objects that you can manage by using the OpenShift Container Platform web console or the command line.

OpenShift Virtualization is represented by the OpenShift Virtualization icon.

You can use OpenShift Virtualization the OVN-Kubernetes Container Network Interface (CNI) network provider.

Learn more about what you can do with OpenShift Virtualization.

Learn more about OpenShift Virtualization architecture and deployments.

Prepare your cluster for OpenShift Virtualization.

2.1.2.1. OpenShift Virtualization supported cluster version

OpenShift Virtualization 4.17 is supported for use on OpenShift Container Platform 4.17 clusters. To use the latest z-stream release of OpenShift Virtualization, you must first upgrade to the latest version of OpenShift Container Platform.

2.1.2.2. Supported guest operating systems

To view the supported guest operating systems for OpenShift Virtualization, see Certified Guest Operating Systems in Red Hat OpenStack Platform, Red Hat Virtualization, OpenShift Virtualization and Red Hat Enterprise Linux with KVM.

2.1.2.3. Microsoft Windows SVVP certification

OpenShift Virtualization is certified in Microsoft’s Windows Server Virtualization Validation Program (SVVP) to run Windows Server workloads.

The SVVP certification applies to:

  • Red Hat Enterprise Linux CoreOS workers. In the Microsoft SVVP Catalog, they are named Red Hat OpenShift Container Platform 4 on RHEL CoreOS 9.
  • Intel and AMD CPUs.

2.1.3. Quick starts

Quick start tours are available for several OpenShift Virtualization features. To view the tours, click the Help icon ? in the menu bar on the header of the OpenShift Container Platform web console and then select Quick Starts. You can filter the available tours by entering the keyword virtualization in the Filter field.

2.1.4. New and changed features

This release adds new features and enhancements related to the following components and concepts:

2.1.4.1. Infrastructure
  • The inferFromVolume attribute is now supported for use with imported container disks. When requested, OpenShift Virtualization can copy the labels instancetype.kubevirt.io/default-instancetype and instancetype.kubevirt.io/default-preference from a source container disk to the boot volume of a new VM.
  • You can now select a custom namespace for Red Hat golden images instead of using the default openshift-virtualization-os-images namespace. By using a custom namespace, cluster administrators can restrict user access to the default boot sources. To update this setting by using the web console, go to VirtualizationOverviewSettingsClusterGeneral settingsBootable volumes project.
2.1.4.2. Virtualization
  • You can now increase VM workload density on nodes by overcommitting memory (RAM) with the wasp-agent. The wasp agent assigns swap resources to worker nodes and manages pod evictions when nodes are at risk.

    Note

    Overcommitting memory on a highly utilized system can decrease workload performance.

  • Enabling post-copy live migration for VM workloads is now generally available.
  • As a cluster administrator, you can expose USB devices in a cluster, making them available for virtual machine (VM) owners to assign to VMs. You expose a USB device by first enabling host passthrough and then configuring the VM to access the USB device.
  • You can now use the Application-Aware Quota (AAQ) Operator to customize and manage resource quotas for individual components in an OpenShift Container Platform cluster. The AAQ Operator provides the ApplicationAwareResourceQuota and ApplicationAwareClusterResourceQuota custom resource definitions (CRDs) that can be used to allocate resources without interfering with cluster-level activities such as upgrades and node maintenance.
2.1.4.3. Storage
  • The VirtualMachineSnapshot API version is now v1beta1.
  • The VirtualMachineExport API version is now v1beta1.
2.1.4.4. Web console
  • The OpenShift Container Platform web console includes a new focused view, which presents a condensed navigation menu specific to the OpenShift Virtualization perspective. This view complements but does not replace the existing OpenShift Container Platform web console Virtualization navigation options.

    To access the new view, navigate to AdministratorVirtualization in the web console.

  • An OpenShift Virtualization guided tour is now available. You can access the tour by either clicking Start Tour on the Welcome to OpenShift Virtualization dialog or navigating to VirtualizationOverviewSettingsUserGetting started resourcesGuided tour.
  • Hot plugging memory for VMs from the web console is now generally available.
  • Hot plugging CPUs for VMs from the web console is now generally available.

2.1.5. Deprecated and removed features

2.1.5.1. Deprecated features

Deprecated features are included in the current release and supported. However, they will be removed in a future release and are not recommended for new deployments.

  • The DevPreviewLongLifecycle profile is deprecated. The profile is now LongLifecycle and is generally available.
  • The tekton-tasks-operator is deprecated and Tekton tasks and example pipelines are now deployed by the ssp-operator.
  • The copy-template, modify-vm-template, and create-vm-from-template tasks are deprecated.
  • Support for Windows Server 2012 R2 templates is deprecated.
  • The alerts KubeVirtComponentExceedsRequestedMemory and KubeVirtComponentExceedsRequestedCPU are deprecated. You can safely silence them.
2.1.5.2. Removed features

Removed features are those that were deprecated in earlier releases. They are now removed from OpenShift Virtualization and are no longer supported.

  • CentOS 7 and CentOS Stream 8 are now in the End of Life phase. As a consequence, the container images for these operating systems have been removed from OpenShift Virtualization and are no longer community supported.

2.1.6. Technology Preview features

Some features in this release are currently in Technology Preview. These experimental features are not intended for production use. Note the following scope of support on the Red Hat Customer Portal for these features:

Technology Preview Features Support Scope

  • You can now migrate storage classes for running and stopped VMs.

    Note

    Storage live migration is not enabled by default in the HyperConverged custom resource. To enable the required feature gates, follow the workaround documented in Enable storage live migration in OpenShift Virtualization 4.17 in the Red Hat knowledge base.

2.1.7. Known issues

Nodes
  • Uninstalling OpenShift Virtualization does not remove the feature.node.kubevirt.io node labels created by OpenShift Virtualization. You must remove the labels manually. (CNV-38543)
  • In a heterogeneous cluster with different compute nodes, virtual machines that have HyperV reenlightenment enabled cannot be scheduled on nodes that do not support timestamp-counter scaling (TSC) or have the appropriate TSC frequency. (BZ#2151169)
Storage
  • If you clone more than 100 VMs using the csi-clone cloning strategy, then the Ceph CSI might not purge the clones. Manually deleting the clones might also fail. (CNV-23501)

    • As a workaround, you can restart the ceph-mgr to purge the VM clones.
Virtualization
  • When adding a virtual Trusted Platform Module (vTPM) device to a Windows VM, the BitLocker Drive Encryption system check passes even if the vTPM device is not persistent. This is because a vTPM device that is not persistent stores and recovers encryption keys using ephemeral storage for the lifetime of the virt-launcher pod. When the VM migrates or is shut down and restarts, the vTPM data is lost. (CNV-36448)
  • OpenShift Virtualization links a service account token in use by a pod to that specific pod. OpenShift Virtualization implements a service account volume by creating a disk image that contains a token. If you migrate a VM, then the service account volume becomes invalid. (CNV-33835)

    • As a workaround, use user accounts rather than service accounts because user account tokens are not bound to a specific pod.
Web console
  • When you create a persistent volume claim (PVC) by selecting With Data upload form from the Create PersistentVolumeClaim list in the web console, uploading data to the PVC by using the Upload Data field fails. (CNV-37607)

Chapter 3. Getting started

3.1. Getting started with OpenShift Virtualization

You can explore the features and functionalities of OpenShift Virtualization by installing and configuring a basic environment.

Note

Cluster configuration procedures require cluster-admin privileges.

3.1.1. Tours and quick starts

You can start exploring OpenShift Virtualization by taking tours in the OpenShift Container Platform web console.

Getting started tour

This short guided tour introduces several key aspects of using OpenShift Virtualization. There are two ways to start the tour:

  • On the Welcome to OpenShift Virtualization dialog, click Start Tour.
  • Go to VirtualizationOverviewSettingsUserGetting started resources and click Guided tour.
Quick starts

Quick start tours are available for several OpenShift Virtualization features. To access quick starts, complete the following steps:

  1. Click the Help icon ? in the menu bar on the header of the OpenShift Container Platform web console.
  2. Select Quick Starts.

You can filter the available tours by entering the keyword virtualization in the Filter field.

3.1.2. Planning and installing OpenShift Virtualization

Plan and install OpenShift Virtualization on an OpenShift Container Platform cluster:

Planning and installation resources

3.1.3. Creating and managing virtual machines

Create a virtual machine (VM):

Connect a VM to a secondary network:

Connect to a VM:

Manage a VM:

3.1.4. Next steps

3.2. Using the CLI tools

You can manage OpenShift Virtualization resources by using the virtctl command line tool.

You can access and modify virtual machine (VM) disk images by using the libguestfs command line tool. You deploy libguestfs by using the virtctl libguestfs command.

3.2.1. Installing virtctl

To install virtctl on Red Hat Enterprise Linux (RHEL) 9, Linux, Windows, and MacOS operating systems, you download and install the virtctl binary file.

To install virtctl on RHEL 8, you enable the OpenShift Virtualization repository and then install the kubevirt-virtctl package.

3.2.1.1. Installing the virtctl binary on RHEL 9, Linux, Windows, or macOS

You can download the virtctl binary for your operating system from the OpenShift Container Platform web console and then install it.

Procedure

  1. Navigate to the Virtualization → Overview page in the web console.
  2. Click the Download virtctl link to download the virtctl binary for your operating system.
  3. Install virtctl:

    • For RHEL 9 and other Linux operating systems:

      1. Decompress the archive file:

        $ tar -xvf <virtctl-version-distribution.arch>.tar.gz
      2. Run the following command to make the virtctl binary executable:

        $ chmod +x <path/virtctl-file-name>
      3. Move the virtctl binary to a directory in your PATH environment variable.

        You can check your path by running the following command:

        $ echo $PATH
      4. Set the KUBECONFIG environment variable:

        $ export KUBECONFIG=/home/<user>/clusters/current/auth/kubeconfig
    • For Windows:

      1. Decompress the archive file.
      2. Navigate the extracted folder hierarchy and double-click the virtctl executable file to install the client.
      3. Move the virtctl binary to a directory in your PATH environment variable.

        You can check your path by running the following command:

        C:\> path
    • For macOS:

      1. Decompress the archive file.
      2. Move the virtctl binary to a directory in your PATH environment variable.

        You can check your path by running the following command:

        echo $PATH
3.2.1.2. Installing the virtctl RPM on RHEL 8

You can install the virtctl RPM package on Red Hat Enterprise Linux (RHEL) 8 by enabling the OpenShift Virtualization repository and installing the kubevirt-virtctl package.

Prerequisites

  • Each host in your cluster must be registered with Red Hat Subscription Manager (RHSM) and have an active OpenShift Container Platform subscription.

Procedure

  1. Enable the OpenShift Virtualization repository by using the subscription-manager CLI tool to run the following command:

    # subscription-manager repos --enable cnv-4.17-for-rhel-8-x86_64-rpms
  2. Install the kubevirt-virtctl package by running the following command:

    # yum install kubevirt-virtctl

3.2.2. virtctl commands

The virtctl client is a command-line utility for managing OpenShift Virtualization resources.

Note

The virtual machine (VM) commands also apply to virtual machine instances (VMIs) unless otherwise specified.

3.2.2.1. virtctl information commands

You use virtctl information commands to view information about the virtctl client.

Table 3.1. Information commands
CommandDescription

virtctl version

View the virtctl client and server versions.

virtctl help

View a list of virtctl commands.

virtctl <command> -h|--help

View a list of options for a specific command.

virtctl options

View a list of global command options for any virtctl command.

3.2.2.2. VM information commands

You can use virtctl to view information about virtual machines (VMs) and virtual machine instances (VMIs).

Table 3.2. VM information commands
CommandDescription

virtctl fslist <vm_name>

View the file systems available on a guest machine.

virtctl guestosinfo <vm_name>

View information about the operating systems on a guest machine.

virtctl userlist <vm_name>

View the logged-in users on a guest machine.

3.2.2.3. VM manifest creation commands

You can use virtctl create commands to create manifests for virtual machines, instance types, and preferences.

Table 3.3. VM manifest creation commands
CommandDescription
virtctl create vm

Create a VirtualMachine (VM) manifest.

virtctl create vm --name <vm_name>

Create a VM manifest, specifying a name for the VM.

virtctl create vm --instancetype <instancetype_name>

Create a VM manifest that uses an existing cluster-wide instance type.

virtctl create vm --instancetype=virtualmachineinstancetype/<instancetype_name>

Create a VM manifest that uses an existing namespaced instance type.

virtctl create instancetype --cpu <cpu_value> --memory <memory_value> --name <instancetype_name>

Create a manifest for a cluster-wide instance type.

virtctl create instancetype --cpu <cpu_value> --memory <memory_value> --name <instancetype_name> --namespace <namespace_value>

Create a manifest for a namespaced instance type.

virtctl create preference --name <preference_name>

Create a manifest for a cluster-wide VM preference, specifying a name for the preference.

virtctl create preference --namespace <namespace_value>

Create a manifest for a namespaced VM preference.

3.2.2.4. VM management commands

You use virtctl virtual machine (VM) management commands to manage and migrate virtual machines (VMs) and virtual machine instances (VMIs).

Table 3.4. VM management commands
CommandDescription

virtctl start <vm_name>

Start a VM.

virtctl start --paused <vm_name>

Start a VM in a paused state. This option enables you to interrupt the boot process from the VNC console.

virtctl stop <vm_name>

Stop a VM.

virtctl stop <vm_name> --grace-period 0 --force

Force stop a VM. This option might cause data inconsistency or data loss.

virtctl pause vm <vm_name>

Pause a VM. The machine state is kept in memory.

virtctl unpause vm <vm_name>

Unpause a VM.

virtctl migrate <vm_name>

Migrate a VM.

virtctl migrate-cancel <vm_name>

Cancel a VM migration.

virtctl restart <vm_name>

Restart a VM.

3.2.2.5. VM connection commands

You use virtctl connection commands to expose ports and connect to virtual machines (VMs) and virtual machine instances (VMIs).

Table 3.5. VM connection commands
CommandDescription

virtctl console <vm_name>

Connect to the serial console of a VM.

virtctl expose vm <vm_name> --name <service_name> --type <ClusterIP|NodePort|LoadBalancer> --port <port>

Create a service that forwards a designated port of a VM and expose the service on the specified port of the node.

Example: virtctl expose vm rhel9_vm --name rhel9-ssh --type NodePort --port 22

virtctl scp -i <ssh_key> <file_name> <user_name>@<vm_name>

Copy a file from your machine to a VM. This command uses the private key of an SSH key pair. The VM must be configured with the public key.

virtctl scp -i <ssh_key> <user_name@<vm_name>:<file_name> .

Copy a file from a VM to your machine. This command uses the private key of an SSH key pair. The VM must be configured with the public key.

virtctl ssh -i <ssh_key> <user_name>@<vm_name>

Open an SSH connection with a VM. This command uses the private key of an SSH key pair. The VM must be configured with the public key.

virtctl vnc <vm_name>

Connect to the VNC console of a VM.

You must have virt-viewer installed.

virtctl vnc --proxy-only=true <vm_name>

Display the port number and connect manually to a VM by using any viewer through the VNC connection.

virtctl vnc --port=<port-number> <vm_name>

Specify a port number to run the proxy on the specified port, if that port is available.

If a port number is not specified, the proxy runs on a random port.

3.2.2.6. VM export commands

Use virtctl vmexport commands to create, download, or delete a volume exported from a VM, VM snapshot, or persistent volume claim (PVC). Certain manifests also contain a header secret, which grants access to the endpoint to import a disk image in a format that OpenShift Virtualization can use.

Table 3.6. VM export commands
CommandDescription

virtctl vmexport create <vmexport_name> --vm|snapshot|pvc=<object_name>

Create a VirtualMachineExport custom resource (CR) to export a volume from a VM, VM snapshot, or PVC.

  • --vm: Exports the PVCs of a VM.
  • --snapshot: Exports the PVCs contained in a VirtualMachineSnapshot CR.
  • --pvc: Exports a PVC.
  • Optional: --ttl=1h specifies the time to live. The default duration is 2 hours.

virtctl vmexport delete <vmexport_name>

Delete a VirtualMachineExport CR manually.

virtctl vmexport download <vmexport_name> --output=<output_file> --volume=<volume_name>

Download the volume defined in a VirtualMachineExport CR.

  • --output specifies the file format. Example: disk.img.gz.
  • --volume specifies the volume to download. This flag is optional if only one volume is available.

Optional:

  • --keep-vme retains the VirtualMachineExport CR after download. The default behavior is to delete the VirtualMachineExport CR after download.
  • --insecure enables an insecure HTTP connection.

virtctl vmexport download <vmexport_name> --<vm|snapshot|pvc>=<object_name> --output=<output_file> --volume=<volume_name>

Create a VirtualMachineExport CR and then download the volume defined in the CR.

virtctl vmexport download export --manifest

Retrieve the manifest for an existing export. The manifest does not include the header secret.

virtctl vmexport download export --manifest --vm=example

Create a VM export for a VM example, and retrieve the manifest. The manifest does not include the header secret.

virtctl vmexport download export --manifest --snap=example

Create a VM export for a VM snapshot example, and retrieve the manifest. The manifest does not include the header secret.

virtctl vmexport download export --manifest --include-secret

Retrieve the manifest for an existing export. The manifest includes the header secret.

virtctl vmexport download export --manifest --manifest-output-format=json

Retrieve the manifest for an existing export in json format. The manifest does not include the header secret.

virtctl vmexport download export --manifest --include-secret --output=manifest.yaml

Retrieve the manifest for an existing export. The manifest includes the header secret and writes it to the file specified.

3.2.2.7. VM memory dump commands

You can use the virtctl memory-dump command to output a VM memory dump on a PVC. You can specify an existing PVC or use the --create-claim flag to create a new PVC.

Prerequisites

  • The PVC volume mode must be FileSystem.
  • The PVC must be large enough to contain the memory dump.

    The formula for calculating the PVC size is (VMMemorySize + 100Mi) * FileSystemOverhead, where 100Mi is the memory dump overhead.

  • You must enable the hot plug feature gate in the HyperConverged custom resource by running the following command:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
      --type json -p '[{"op": "add", "path": "/spec/featureGates", \
      "value": "HotplugVolumes"}]'

Downloading the memory dump

You must use the virtctl vmexport download command to download the memory dump:

$ virtctl vmexport download <vmexport_name> --vm|pvc=<object_name> \
  --volume=<volume_name> --output=<output_file>
Table 3.7. VM memory dump commands
CommandDescription

virtctl memory-dump get <vm_name> --claim-name=<pvc_name>

Save the memory dump of a VM on a PVC. The memory dump status is displayed in the status section of the VirtualMachine resource.

Optional:

  • --create-claim creates a new PVC with the appropriate size. This flag has the following options:

    • --storage-class=<storage_class>: Specify a storage class for the PVC.
    • --access-mode=<access_mode>: Specify ReadWriteOnce or ReadWriteMany.

virtctl memory-dump get <vm_name>

Rerun the virtctl memory-dump command with the same PVC.

This command overwrites the previous memory dump.

virtctl memory-dump remove <vm_name>

Remove a memory dump.

You must remove a memory dump manually if you want to change the target PVC.

This command removes the association between the VM and the PVC, so that the memory dump is not displayed in the status section of the VirtualMachine resource. The PVC is not affected.

3.2.2.8. Hot plug and hot unplug commands

You use virtctl to add or remove resources from running virtual machines (VMs) and virtual machine instances (VMIs).

Table 3.8. Hot plug and hot unplug commands
CommandDescription

virtctl addvolume <vm_name> --volume-name=<datavolume_or_PVC> [--persist] [--serial=<label>]

Hot plug a data volume or persistent volume claim (PVC).

Optional:

  • --persist mounts the virtual disk permanently on a VM. This flag does not apply to VMIs.
  • --serial=<label> adds a label to the VM. If you do not specify a label, the default label is the data volume or PVC name.

virtctl removevolume <vm_name> --volume-name=<virtual_disk>

Hot unplug a virtual disk.

virtctl addinterface <vm_name> --network-attachment-definition-name <net_attach_def_name> --name <interface_name>

Hot plug a Linux bridge network interface.

virtctl removeinterface <vm_name> --name <interface_name>

Hot unplug a Linux bridge network interface.

3.2.2.9. Image upload commands

You use the virtctl image-upload commands to upload a VM image to a data volume.

Table 3.9. Image upload commands
CommandDescription

virtctl image-upload dv <datavolume_name> --image-path=</path/to/image> --no-create

Upload a VM image to a data volume that already exists.

virtctl image-upload dv <datavolume_name> --size=<datavolume_size> --image-path=</path/to/image>

Upload a VM image to a new data volume of a specified requested size.

3.2.3. Deploying libguestfs by using virtctl

You can use the virtctl guestfs command to deploy an interactive container with libguestfs-tools and a persistent volume claim (PVC) attached to it.

Procedure

  • To deploy a container with libguestfs-tools, mount the PVC, and attach a shell to it, run the following command:

    $ virtctl guestfs -n <namespace> <pvc_name> 1
    1
    The PVC name is a required argument. If you do not include it, an error message appears.
3.2.3.1. Libguestfs and virtctl guestfs commands

Libguestfs tools help you access and modify virtual machine (VM) disk images. You can use libguestfs tools to view and edit files in a guest, clone and build virtual machines, and format and resize disks.

You can also use the virtctl guestfs command and its sub-commands to modify, inspect, and debug VM disks on a PVC. To see a complete list of possible sub-commands, enter virt- on the command line and press the Tab key. For example:

CommandDescription

virt-edit -a /dev/vda /etc/motd

Edit a file interactively in your terminal.

virt-customize -a /dev/vda --ssh-inject root:string:<public key example>

Inject an ssh key into the guest and create a login.

virt-df -a /dev/vda -h

See how much disk space is used by a VM.

virt-customize -a /dev/vda --run-command 'rpm -qa > /rpm-list'

See the full list of all RPMs installed on a guest by creating an output file containing the full list.

virt-cat -a /dev/vda /rpm-list

Display the output file list of all RPMs created using the virt-customize -a /dev/vda --run-command 'rpm -qa > /rpm-list' command in your terminal.

virt-sysprep -a /dev/vda

Seal a virtual machine disk image to be used as a template.

By default, virtctl guestfs creates a session with everything needed to manage a VM disk. However, the command also supports several flag options if you want to customize the behavior:

Flag OptionDescription

--h or --help

Provides help for guestfs.

-n <namespace> option with a <pvc_name> argument

To use a PVC from a specific namespace.

If you do not use the -n <namespace> option, your current project is used. To change projects, use oc project <namespace>.

If you do not include a <pvc_name> argument, an error message appears.

--image string

Lists the libguestfs-tools container image.

You can configure the container to use a custom image by using the --image option.

--kvm

Indicates that kvm is used by the libguestfs-tools container.

By default, virtctl guestfs sets up kvm for the interactive container, which greatly speeds up the libguest-tools execution because it uses QEMU.

If a cluster does not have any kvm supporting nodes, you must disable kvm by setting the option --kvm=false.

If not set, the libguestfs-tools pod remains pending because it cannot be scheduled on any node.

--pull-policy string

Shows the pull policy for the libguestfs image.

You can also overwrite the image’s pull policy by setting the pull-policy option.

The command also checks if a PVC is in use by another pod, in which case an error message appears. However, once the libguestfs-tools process starts, the setup cannot avoid a new pod using the same PVC. You must verify that there are no active virtctl guestfs pods before starting the VM that accesses the same PVC.

Note

The virtctl guestfs command accepts only a single PVC attached to the interactive pod.

3.2.4. Using Ansible

To use the Ansible collection for OpenShift Virtualization, see Red Hat Ansible Automation Hub (Red Hat Hybrid Cloud Console).

Chapter 4. Installing

4.1. Preparing your cluster for OpenShift Virtualization

Review this section before you install OpenShift Virtualization to ensure that your cluster meets the requirements.

Important
Installation method considerations
You can use any installation method, including user-provisioned, installer-provisioned, or assisted installer, to deploy OpenShift Container Platform. However, the installation method and the cluster topology might affect OpenShift Virtualization functionality, such as snapshots or live migration.
Red Hat OpenShift Data Foundation
If you deploy OpenShift Virtualization with Red Hat OpenShift Data Foundation, you must create a dedicated storage class for Windows virtual machine disks. See Optimizing ODF PersistentVolumes for Windows VMs for details.
IPv6
You cannot run OpenShift Virtualization on a single-stack IPv6 cluster.

FIPS mode

If you install your cluster in FIPS mode, no additional setup is required for OpenShift Virtualization.

4.1.1. Supported platforms

You can use the following platforms with OpenShift Virtualization:

Bare metal instances or servers offered by other cloud providers are not supported.

4.1.1.1. OpenShift Virtualization on AWS bare metal

You can run OpenShift Virtualization on an Amazon Web Services (AWS) bare-metal OpenShift Container Platform cluster.

Note

OpenShift Virtualization is also supported on Red Hat OpenShift Service on AWS (ROSA) Classic clusters, which have the same configuration requirements as AWS bare-metal clusters.

Before you set up your cluster, review the following summary of supported features and limitations:

Installing
  • You can install the cluster by using installer-provisioned infrastructure, ensuring that you specify bare-metal instance types for the worker nodes. For example, you can use the c5n.metal type value for a machine based on x86_64 architecture. You specify bare-metal instance types by editing the install-config.yaml file.

    For more information, see the OpenShift Container Platform documentation about installing on AWS.

Accessing virtual machines (VMs)
  • There is no change to how you access VMs by using the virtctl CLI tool or the OpenShift Container Platform web console.
  • You can expose VMs by using a NodePort or LoadBalancer service.

    • The load balancer approach is preferable because OpenShift Container Platform automatically creates the load balancer in AWS and manages its lifecycle. A security group is also created for the load balancer, and you can use annotations to attach existing security groups. When you remove the service, OpenShift Container Platform removes the load balancer and its associated resources.
Networking
  • You cannot use Single Root I/O Virtualization (SR-IOV) or bridge Container Network Interface (CNI) networks, including virtual LAN (VLAN). If your application requires a flat layer 2 network or control over the IP pool, consider using OVN-Kubernetes secondary overlay networks.
Storage
  • You can use any storage solution that is certified by the storage vendor to work with the underlying platform.

    Important

    AWS bare-metal and ROSA clusters might have different supported storage solutions. Ensure that you confirm support with your storage vendor.

  • Using Amazon Elastic File System (EFS) or Amazon Elastic Block Store (EBS) with OpenShift Virtualization might cause performance and functionality limitations as shown in the following table:

    Table 4.1. EFS and EBS performance and functionality limitations
    FeatureEBS volumeEFS volumeShared storage solutions
     

    gp2

    gp3

    io2

      

    VM live migration

    Not available

    Not available

    Available

    Available

    Available

    Fast VM creation by using cloning

    Available

    Not available

    Available

    VM backup and restore by using snapshots

    Available

    Not available

    Available

    Consider using CSI storage, which supports ReadWriteMany (RWX), cloning, and snapshots to enable live migration, fast VM creation, and VM snapshots capabilities.

Hosted control planes (HCPs)
  • HCPs for OpenShift Virtualization are not currently supported on AWS infrastructure.

4.1.2. Hardware and operating system requirements

Review the following hardware and operating system requirements for OpenShift Virtualization.

4.1.2.1. CPU requirements
  • Supported by Red Hat Enterprise Linux (RHEL) 9.

    See Red Hat Ecosystem Catalog for supported CPUs.

    Note

    If your worker nodes have different CPUs, live migration failures might occur because different CPUs have different capabilities. You can mitigate this issue by ensuring that your worker nodes have CPUs with the appropriate capacity and by configuring node affinity rules for your virtual machines.

    See Configuring a required node affinity rule for details.

  • Support for AMD and Intel 64-bit architectures (x86-64-v2).
  • Support for Intel 64 or AMD64 CPU extensions.
  • Intel VT or AMD-V hardware virtualization extensions enabled.
  • NX (no execute) flag enabled.
4.1.2.2. Operating system requirements
  • Red Hat Enterprise Linux CoreOS (RHCOS) installed on worker nodes.

    See About RHCOS for details.

    Note

    RHEL worker nodes are not supported.

4.1.2.3. Storage requirements
  • Supported by OpenShift Container Platform. See Optimizing storage.
  • You must create a default OpenShift Virtualization or OpenShift Container Platform storage class. The purpose of this is to address the unique storage needs of VM workloads and offer optimized performance, reliability, and user experience. If both OpenShift Virtualization and OpenShift Container Platform default storage classes exist, the OpenShift Virtualization class takes precedence when creating VM disks.
Note

To mark a storage class as the default for virtualization workloads, set the annotation storageclass.kubevirt.io/is-default-virt-class to "true".

  • If the storage provisioner supports snapshots, you must associate a VolumeSnapshotClass object with the default storage class.
4.1.2.3.1. About volume and access modes for virtual machine disks

If you use the storage API with known storage providers, the volume and access modes are selected automatically. However, if you use a storage class that does not have a storage profile, you must configure the volume and access mode.

For best results, use the ReadWriteMany (RWX) access mode and the Block volume mode. This is important for the following reasons:

  • ReadWriteMany (RWX) access mode is required for live migration.
  • The Block volume mode performs significantly better than the Filesystem volume mode. This is because the Filesystem volume mode uses more storage layers, including a file system layer and a disk image file. These layers are not necessary for VM disk storage.

    For example, if you use Red Hat OpenShift Data Foundation, Ceph RBD volumes are preferable to CephFS volumes.

Important

You cannot live migrate virtual machines with the following configurations:

  • Storage volume with ReadWriteOnce (RWO) access mode
  • Passthrough features such as GPUs

Set the evictionStrategy field to None for these virtual machines. The None strategy powers down VMs during node reboots.

4.1.3. Live migration requirements

  • Shared storage with ReadWriteMany (RWX) access mode.
  • Sufficient RAM and network bandwidth.

    Note

    You must ensure that there is enough memory request capacity in the cluster to support node drains that result in live migrations. You can determine the approximate required spare memory by using the following calculation:

    Product of (Maximum number of nodes that can drain in parallel) and (Highest total VM memory request allocations across nodes)

    The default number of migrations that can run in parallel in the cluster is 5.

  • If the virtual machine uses a host model CPU, the nodes must support the virtual machine’s host model CPU.
  • A dedicated Multus network for live migration is highly recommended. A dedicated network minimizes the effects of network saturation on tenant workloads during migration.

4.1.4. Physical resource overhead requirements

OpenShift Virtualization is an add-on to OpenShift Container Platform and imposes additional overhead that you must account for when planning a cluster. Each cluster machine must accommodate the following overhead requirements in addition to the OpenShift Container Platform requirements. Oversubscribing the physical resources in a cluster can affect performance.

Important

The numbers noted in this documentation are based on Red Hat’s test methodology and setup. These numbers can vary based on your own individual setup and environments.

Memory overhead

Calculate the memory overhead values for OpenShift Virtualization by using the equations below.

Cluster memory overhead

Memory overhead per infrastructure node ≈ 150 MiB

Memory overhead per worker node ≈ 360 MiB

Additionally, OpenShift Virtualization environment resources require a total of 2179 MiB of RAM that is spread across all infrastructure nodes.

Virtual machine memory overhead

Memory overhead per virtual machine ≈ (1.002 × requested memory) \
              + 218 MiB \ 1
              + 8 MiB × (number of vCPUs) \ 2
              + 16 MiB × (number of graphics devices) \ 3
              + (additional memory overhead) 4

1
Required for the processes that run in the virt-launcher pod.
2
Number of virtual CPUs requested by the virtual machine.
3
Number of virtual graphics cards requested by the virtual machine.
4
Additional memory overhead:
  • If your environment includes a Single Root I/O Virtualization (SR-IOV) network device or a Graphics Processing Unit (GPU), allocate 1 GiB additional memory overhead for each device.
  • If Secure Encrypted Virtualization (SEV) is enabled, add 256 MiB.
  • If Trusted Platform Module (TPM) is enabled, add 53 MiB.
CPU overhead

Calculate the cluster processor overhead requirements for OpenShift Virtualization by using the equation below. The CPU overhead per virtual machine depends on your individual setup.

Cluster CPU overhead

CPU overhead for infrastructure nodes ≈ 4 cores

OpenShift Virtualization increases the overall utilization of cluster level services such as logging, routing, and monitoring. To account for this workload, ensure that nodes that host infrastructure components have capacity allocated for 4 additional cores (4000 millicores) distributed across those nodes.

CPU overhead for worker nodes ≈ 2 cores + CPU overhead per virtual machine

Each worker node that hosts virtual machines must have capacity for 2 additional cores (2000 millicores) for OpenShift Virtualization management workloads in addition to the CPUs required for virtual machine workloads.

Virtual machine CPU overhead

If dedicated CPUs are requested, there is a 1:1 impact on the cluster CPU overhead requirement. Otherwise, there are no specific rules about how many CPUs a virtual machine requires.

Storage overhead

Use the guidelines below to estimate storage overhead requirements for your OpenShift Virtualization environment.

Cluster storage overhead

Aggregated storage overhead per node ≈ 10 GiB

10 GiB is the estimated on-disk storage impact for each node in the cluster when you install OpenShift Virtualization.

Virtual machine storage overhead

Storage overhead per virtual machine depends on specific requests for resource allocation within the virtual machine. The request could be for ephemeral storage on the node or storage resources hosted elsewhere in the cluster. OpenShift Virtualization does not currently allocate any additional ephemeral storage for the running container itself.

Example

As a cluster administrator, if you plan to host 10 virtual machines in the cluster, each with 1 GiB of RAM and 2 vCPUs, the memory impact across the cluster is 11.68 GiB. The estimated on-disk storage impact for each node in the cluster is 10 GiB and the CPU impact for worker nodes that host virtual machine workloads is a minimum of 2 cores.

4.1.5. Single-node OpenShift differences

You can install OpenShift Virtualization on single-node OpenShift.

However, you should be aware that Single-node OpenShift does not support the following features:

  • High availability
  • Pod disruption
  • Live migration
  • Virtual machines or templates that have an eviction strategy configured

4.1.6. Object maximums

You must consider the following tested object maximums when planning your cluster:

4.1.7. Cluster high-availability options

You can configure one of the following high-availability (HA) options for your cluster:

  • Automatic high availability for installer-provisioned infrastructure (IPI) is available by deploying machine health checks.

    Note

    In OpenShift Container Platform clusters installed using installer-provisioned infrastructure and with a properly configured MachineHealthCheck resource, if a node fails the machine health check and becomes unavailable to the cluster, it is recycled. What happens next with VMs that ran on the failed node depends on a series of conditions. See Run strategies for more detailed information about the potential outcomes and how run strategies affect those outcomes.

  • Automatic high availability for both IPI and non-IPI is available by using the Node Health Check Operator on the OpenShift Container Platform cluster to deploy the NodeHealthCheck controller. The controller identifies unhealthy nodes and uses a remediation provider, such as the Self Node Remediation Operator or Fence Agents Remediation Operator, to remediate the unhealthy nodes. For more information on remediation, fencing, and maintaining nodes, see the Workload Availability for Red Hat OpenShift documentation.
  • High availability for any platform is available by using either a monitoring system or a qualified human to monitor node availability. When a node is lost, shut it down and run oc delete node <lost_node>.

    Note

    Without an external monitoring system or a qualified human monitoring node health, virtual machines lose high availability.

4.2. Installing OpenShift Virtualization

Install OpenShift Virtualization to add virtualization functionality to your OpenShift Container Platform cluster.

Important

If you install OpenShift Virtualization in a restricted environment with no internet connectivity, you must configure Operator Lifecycle Manager for disconnected environments.

If you have limited internet connectivity, you can configure proxy support in OLM to access the OperatorHub.

4.2.1. Installing the OpenShift Virtualization Operator

Install the OpenShift Virtualization Operator by using the OpenShift Container Platform web console or the command line.

4.2.1.1. Installing the OpenShift Virtualization Operator by using the web console

You can deploy the OpenShift Virtualization Operator by using the OpenShift Container Platform web console.

Prerequisites

  • Install OpenShift Container Platform 4.17 on your cluster.
  • Log in to the OpenShift Container Platform web console as a user with cluster-admin permissions.

Procedure

  1. From the Administrator perspective, click OperatorsOperatorHub.
  2. In the Filter by keyword field, type Virtualization.
  3. Select the OpenShift Virtualization Operator tile with the Red Hat source label.
  4. Read the information about the Operator and click Install.
  5. On the Install Operator page:

    1. Select stable from the list of available Update Channel options. This ensures that you install the version of OpenShift Virtualization that is compatible with your OpenShift Container Platform version.
    2. For Installed Namespace, ensure that the Operator recommended namespace option is selected. This installs the Operator in the mandatory openshift-cnv namespace, which is automatically created if it does not exist.

      Warning

      Attempting to install the OpenShift Virtualization Operator in a namespace other than openshift-cnv causes the installation to fail.

    3. For Approval Strategy, it is highly recommended that you select Automatic, which is the default value, so that OpenShift Virtualization automatically updates when a new version is available in the stable update channel.

      While it is possible to select the Manual approval strategy, this is inadvisable because of the high risk that it presents to the supportability and functionality of your cluster. Only select Manual if you fully understand these risks and cannot use Automatic.

      Warning

      Because OpenShift Virtualization is only supported when used with the corresponding OpenShift Container Platform version, missing OpenShift Virtualization updates can cause your cluster to become unsupported.

  6. Click Install to make the Operator available to the openshift-cnv namespace.
  7. When the Operator installs successfully, click Create HyperConverged.
  8. Optional: Configure Infra and Workloads node placement options for OpenShift Virtualization components.
  9. Click Create to launch OpenShift Virtualization.

Verification

  • Navigate to the WorkloadsPods page and monitor the OpenShift Virtualization pods until they are all Running. After all the pods display the Running state, you can use OpenShift Virtualization.
4.2.1.2. Installing the OpenShift Virtualization Operator by using the command line

Subscribe to the OpenShift Virtualization catalog and install the OpenShift Virtualization Operator by applying manifests to your cluster.

4.2.1.2.1. Subscribing to the OpenShift Virtualization catalog by using the CLI

Before you install OpenShift Virtualization, you must subscribe to the OpenShift Virtualization catalog. Subscribing gives the openshift-cnv namespace access to the OpenShift Virtualization Operators.

To subscribe, configure Namespace, OperatorGroup, and Subscription objects by applying a single manifest to your cluster.

Prerequisites

  • Install OpenShift Container Platform 4.17 on your cluster.
  • Install the OpenShift CLI (oc).
  • Log in as a user with cluster-admin privileges.

Procedure

  1. Create a YAML file that contains the following manifest:

    apiVersion: v1
    kind: Namespace
    metadata:
      name: openshift-cnv
    ---
    apiVersion: operators.coreos.com/v1
    kind: OperatorGroup
    metadata:
      name: kubevirt-hyperconverged-group
      namespace: openshift-cnv
    spec:
      targetNamespaces:
        - openshift-cnv
    ---
    apiVersion: operators.coreos.com/v1alpha1
    kind: Subscription
    metadata:
      name: hco-operatorhub
      namespace: openshift-cnv
    spec:
      source: redhat-operators
      sourceNamespace: openshift-marketplace
      name: kubevirt-hyperconverged
      startingCSV: kubevirt-hyperconverged-operator.v4.17.0
      channel: "stable" 1
    1
    Using the stable channel ensures that you install the version of OpenShift Virtualization that is compatible with your OpenShift Container Platform version.
  2. Create the required Namespace, OperatorGroup, and Subscription objects for OpenShift Virtualization by running the following command:

    $ oc apply -f <file name>.yaml
Note

You can configure certificate rotation parameters in the YAML file.

4.2.1.2.2. Deploying the OpenShift Virtualization Operator by using the CLI

You can deploy the OpenShift Virtualization Operator by using the oc CLI.

Prerequisites

  • Subscribe to the OpenShift Virtualization catalog in the openshift-cnv namespace.
  • Log in as a user with cluster-admin privileges.

Procedure

  1. Create a YAML file that contains the following manifest:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
  2. Deploy the OpenShift Virtualization Operator by running the following command:

    $ oc apply -f <file_name>.yaml

Verification

  • Ensure that OpenShift Virtualization deployed successfully by watching the PHASE of the cluster service version (CSV) in the openshift-cnv namespace. Run the following command:

    $ watch oc get csv -n openshift-cnv

    The following output displays if deployment was successful:

    Example output

    NAME                                      DISPLAY                    VERSION   REPLACES   PHASE
    kubevirt-hyperconverged-operator.v4.17.0   OpenShift Virtualization   4.17.0                Succeeded

4.2.2. Next steps

  • The hostpath provisioner is a local storage provisioner designed for OpenShift Virtualization. If you want to configure local storage for virtual machines, you must enable the hostpath provisioner first.

4.3. Uninstalling OpenShift Virtualization

You uninstall OpenShift Virtualization by using the web console or the command line interface (CLI) to delete the OpenShift Virtualization workloads, the Operator, and its resources.

4.3.1. Uninstalling OpenShift Virtualization by using the web console

You uninstall OpenShift Virtualization by using the web console to perform the following tasks:

Important

You must first delete all virtual machines, and virtual machine instances.

You cannot uninstall OpenShift Virtualization while its workloads remain on the cluster.

4.3.1.1. Deleting the HyperConverged custom resource

To uninstall OpenShift Virtualization, you first delete the HyperConverged custom resource (CR).

Prerequisites

  • You have access to an OpenShift Container Platform cluster using an account with cluster-admin permissions.

Procedure

  1. Navigate to the OperatorsInstalled Operators page.
  2. Select the OpenShift Virtualization Operator.
  3. Click the OpenShift Virtualization Deployment tab.
  4. Click the Options menu kebab beside kubevirt-hyperconverged and select Delete HyperConverged.
  5. Click Delete in the confirmation window.
4.3.1.2. Deleting Operators from a cluster using the web console

Cluster administrators can delete installed Operators from a selected namespace by using the web console.

Prerequisites

  • You have access to an OpenShift Container Platform cluster web console using an account with cluster-admin permissions.

Procedure

  1. Navigate to the OperatorsInstalled Operators page.
  2. Scroll or enter a keyword into the Filter by name field to find the Operator that you want to remove. Then, click on it.
  3. On the right side of the Operator Details page, select Uninstall Operator from the Actions list.

    An Uninstall Operator? dialog box is displayed.

  4. Select Uninstall to remove the Operator, Operator deployments, and pods. Following this action, the Operator stops running and no longer receives updates.

    Note

    This action does not remove resources managed by the Operator, including custom resource definitions (CRDs) and custom resources (CRs). Dashboards and navigation items enabled by the web console and off-cluster resources that continue to run might need manual clean up. To remove these after uninstalling the Operator, you might need to manually delete the Operator CRDs.

4.3.1.3. Deleting a namespace using the web console

You can delete a namespace by using the OpenShift Container Platform web console.

Prerequisites

  • You have access to an OpenShift Container Platform cluster using an account with cluster-admin permissions.

Procedure

  1. Navigate to AdministrationNamespaces.
  2. Locate the namespace that you want to delete in the list of namespaces.
  3. On the far right side of the namespace listing, select Delete Namespace from the Options menu kebab .
  4. When the Delete Namespace pane opens, enter the name of the namespace that you want to delete in the field.
  5. Click Delete.
4.3.1.4. Deleting OpenShift Virtualization custom resource definitions

You can delete the OpenShift Virtualization custom resource definitions (CRDs) by using the web console.

Prerequisites

  • You have access to an OpenShift Container Platform cluster using an account with cluster-admin permissions.

Procedure

  1. Navigate to AdministrationCustomResourceDefinitions.
  2. Select the Label filter and enter operators.coreos.com/kubevirt-hyperconverged.openshift-cnv in the Search field to display the OpenShift Virtualization CRDs.
  3. Click the Options menu kebab beside each CRD and select Delete CustomResourceDefinition.

4.3.2. Uninstalling OpenShift Virtualization by using the CLI

You can uninstall OpenShift Virtualization by using the OpenShift CLI (oc).

Prerequisites

  • You have access to an OpenShift Container Platform cluster using an account with cluster-admin permissions.
  • You have installed the OpenShift CLI (oc).
  • You have deleted all virtual machines and virtual machine instances. You cannot uninstall OpenShift Virtualization while its workloads remain on the cluster.

Procedure

  1. Delete the HyperConverged custom resource:

    $ oc delete HyperConverged kubevirt-hyperconverged -n openshift-cnv
  2. Delete the OpenShift Virtualization Operator subscription:

    $ oc delete subscription kubevirt-hyperconverged -n openshift-cnv
  3. Delete the OpenShift Virtualization ClusterServiceVersion resource:

    $ oc delete csv -n openshift-cnv -l operators.coreos.com/kubevirt-hyperconverged.openshift-cnv
  4. Delete the OpenShift Virtualization namespace:

    $ oc delete namespace openshift-cnv
  5. List the OpenShift Virtualization custom resource definitions (CRDs) by running the oc delete crd command with the dry-run option:

    $ oc delete crd --dry-run=client -l operators.coreos.com/kubevirt-hyperconverged.openshift-cnv

    Example output

    customresourcedefinition.apiextensions.k8s.io "cdis.cdi.kubevirt.io" deleted (dry run)
    customresourcedefinition.apiextensions.k8s.io "hostpathprovisioners.hostpathprovisioner.kubevirt.io" deleted (dry run)
    customresourcedefinition.apiextensions.k8s.io "hyperconvergeds.hco.kubevirt.io" deleted (dry run)
    customresourcedefinition.apiextensions.k8s.io "kubevirts.kubevirt.io" deleted (dry run)
    customresourcedefinition.apiextensions.k8s.io "networkaddonsconfigs.networkaddonsoperator.network.kubevirt.io" deleted (dry run)
    customresourcedefinition.apiextensions.k8s.io "ssps.ssp.kubevirt.io" deleted (dry run)
    customresourcedefinition.apiextensions.k8s.io "tektontasks.tektontasks.kubevirt.io" deleted (dry run)

  6. Delete the CRDs by running the oc delete crd command without the dry-run option:

    $ oc delete crd -l operators.coreos.com/kubevirt-hyperconverged.openshift-cnv

Chapter 5. Postinstallation configuration

5.1. Postinstallation configuration

The following procedures are typically performed after OpenShift Virtualization is installed. You can configure the components that are relevant for your environment:

5.2. Specifying nodes for OpenShift Virtualization components

The default scheduling for virtual machines (VMs) on bare metal nodes is appropriate. Optionally, you can specify the nodes where you want to deploy OpenShift Virtualization Operators, workloads, and controllers by configuring node placement rules.

Note

You can configure node placement rules for some components after installing OpenShift Virtualization, but virtual machines cannot be present if you want to configure node placement rules for workloads.

5.2.1. About node placement rules for OpenShift Virtualization components

You can use node placement rules for the following tasks:

  • Deploy virtual machines only on nodes intended for virtualization workloads.
  • Deploy Operators only on infrastructure nodes.
  • Maintain separation between workloads.

Depending on the object, you can use one or more of the following rule types:

nodeSelector
Allows pods to be scheduled on nodes that are labeled with the key-value pair or pairs that you specify in this field. The node must have labels that exactly match all listed pairs.
affinity
Enables you to use more expressive syntax to set rules that match nodes with pods. Affinity also allows for more nuance in how the rules are applied. For example, you can specify that a rule is a preference, not a requirement. If a rule is a preference, pods are still scheduled when the rule is not satisfied.
tolerations
Allows pods to be scheduled on nodes that have matching taints. If a taint is applied to a node, that node only accepts pods that tolerate the taint.

5.2.2. Applying node placement rules

You can apply node placement rules by editing a Subscription, HyperConverged, or HostPathProvisioner object using the command line.

Prerequisites

  • The oc CLI tool is installed.
  • You are logged in with cluster administrator permissions.

Procedure

  1. Edit the object in your default editor by running the following command:

    $ oc edit <resource_type> <resource_name> -n {CNVNamespace}
  2. Save the file to apply the changes.

5.2.3. Node placement rule examples

You can specify node placement rules for a OpenShift Virtualization component by editing a Subscription, HyperConverged, or HostPathProvisioner object.

5.2.3.1. Subscription object node placement rule examples

To specify the nodes where OLM deploys the OpenShift Virtualization Operators, edit the Subscription object during OpenShift Virtualization installation.

Currently, you cannot configure node placement rules for the Subscription object by using the web console.

The Subscription object does not support the affinity node pplacement rule.

Example Subscription object with nodeSelector rule

apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: hco-operatorhub
  namespace: openshift-cnv
spec:
  source: redhat-operators
  sourceNamespace: openshift-marketplace
  name: kubevirt-hyperconverged
  startingCSV: kubevirt-hyperconverged-operator.v4.17.0
  channel: "stable"
  config:
    nodeSelector:
      example.io/example-infra-key: example-infra-value 1

1
OLM deploys the OpenShift Virtualization Operators on nodes labeled example.io/example-infra-key = example-infra-value.

Example Subscription object with tolerations rule

apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: hco-operatorhub
  namespace: openshift-cnv
spec:
  source:  redhat-operators
  sourceNamespace: openshift-marketplace
  name: kubevirt-hyperconverged
  startingCSV: kubevirt-hyperconverged-operator.v4.17.0
  channel: "stable"
  config:
    tolerations:
    - key: "key"
      operator: "Equal"
      value: "virtualization" 1
      effect: "NoSchedule"

1
OLM deploys OpenShift Virtualization Operators on nodes labeled key = virtualization:NoSchedule taint. Only pods with the matching tolerations are scheduled on these nodes.
5.2.3.2. HyperConverged object node placement rule example

To specify the nodes where OpenShift Virtualization deploys its components, you can edit the nodePlacement object in the HyperConverged custom resource (CR) file that you create during OpenShift Virtualization installation.

Example HyperConverged object with nodeSelector rule

apiVersion: hco.kubevirt.io/v1beta1
kind: HyperConverged
metadata:
  name: kubevirt-hyperconverged
  namespace: openshift-cnv
spec:
  infra:
    nodePlacement:
      nodeSelector:
        example.io/example-infra-key: example-infra-value 1
  workloads:
    nodePlacement:
      nodeSelector:
        example.io/example-workloads-key: example-workloads-value 2

1
Infrastructure resources are placed on nodes labeled example.io/example-infra-key = example-infra-value.
2
workloads are placed on nodes labeled example.io/example-workloads-key = example-workloads-value.

Example HyperConverged object with affinity rule

apiVersion: hco.kubevirt.io/v1beta1
kind: HyperConverged
metadata:
  name: kubevirt-hyperconverged
  namespace: openshift-cnv
spec:
  infra:
    nodePlacement:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: example.io/example-infra-key
                operator: In
                values:
                - example-infra-value 1
  workloads:
    nodePlacement:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: example.io/example-workloads-key 2
                operator: In
                values:
                - example-workloads-value
          preferredDuringSchedulingIgnoredDuringExecution:
          - weight: 1
            preference:
              matchExpressions:
              - key: example.io/num-cpus
                operator: Gt
                values:
                - 8 3

1
Infrastructure resources are placed on nodes labeled example.io/example-infra-key = example-value.
2
workloads are placed on nodes labeled example.io/example-workloads-key = example-workloads-value.
3
Nodes that have more than eight CPUs are preferred for workloads, but if they are not available, pods are still scheduled.

Example HyperConverged object with tolerations rule

apiVersion: hco.kubevirt.io/v1beta1
kind: HyperConverged
metadata:
  name: kubevirt-hyperconverged
  namespace: openshift-cnv
spec:
  workloads:
    nodePlacement:
      tolerations: 1
      - key: "key"
        operator: "Equal"
        value: "virtualization"
        effect: "NoSchedule"

1
Nodes reserved for OpenShift Virtualization components are labeled with the key = virtualization:NoSchedule taint. Only pods with matching tolerations are scheduled on reserved nodes.
5.2.3.3. HostPathProvisioner object node placement rule example

You can edit the HostPathProvisioner object directly or by using the web console.

Warning

You must schedule the hostpath provisioner and the OpenShift Virtualization components on the same nodes. Otherwise, virtualization pods that use the hostpath provisioner cannot run. You cannot run virtual machines.

After you deploy a virtual machine (VM) with the hostpath provisioner (HPP) storage class, you can remove the hostpath provisioner pod from the same node by using the node selector. However, you must first revert that change, at least for that specific node, and wait for the pod to run before trying to delete the VM.

You can configure node placement rules by specifying nodeSelector, affinity, or tolerations for the spec.workload field of the HostPathProvisioner object that you create when you install the hostpath provisioner.

Example HostPathProvisioner object with nodeSelector rule

apiVersion: hostpathprovisioner.kubevirt.io/v1beta1
kind: HostPathProvisioner
metadata:
  name: hostpath-provisioner
spec:
  imagePullPolicy: IfNotPresent
  pathConfig:
    path: "</path/to/backing/directory>"
    useNamingPrefix: false
  workload:
    nodeSelector:
      example.io/example-workloads-key: example-workloads-value 1

1
Workloads are placed on nodes labeled example.io/example-workloads-key = example-workloads-value.

5.2.4. Additional resources

5.3. Postinstallation network configuration

By default, OpenShift Virtualization is installed with a single, internal pod network.

After you install OpenShift Virtualization, you can install networking Operators and configure additional networks.

5.3.1. Installing networking Operators

You must install the About the Kubernetes NMState Operator to configure a Linux bridge network for live migration or external access to virtual machines (VMs). For installation instructions, see Installing the Kubernetes NMState Operator by using the web console.

You can install the SR-IOV Operator to manage SR-IOV network devices and network attachments. For installation instructions, see Installing the SR-IOV Network Operator..

You can add the About MetalLB and the MetalLB Operator to manage the lifecycle for an instance of MetalLB on your cluster. For installation instructions, see Installing the MetalLB Operator from the OperatorHub using the web console.

5.3.2. Configuring a Linux bridge network

After you install the Kubernetes NMState Operator, you can configure a Linux bridge network for live migration or external access to virtual machines (VMs).

5.3.2.1. Creating a Linux bridge NNCP

You can create a NodeNetworkConfigurationPolicy (NNCP) manifest for a Linux bridge network.

Prerequisites

  • You have installed the Kubernetes NMState Operator.

Procedure

  • Create the NodeNetworkConfigurationPolicy manifest. This example includes sample values that you must replace with your own information.

    apiVersion: nmstate.io/v1
    kind: NodeNetworkConfigurationPolicy
    metadata:
      name: br1-eth1-policy 1
    spec:
      desiredState:
        interfaces:
          - name: br1 2
            description: Linux bridge with eth1 as a port 3
            type: linux-bridge 4
            state: up 5
            ipv4:
              enabled: false 6
            bridge:
              options:
                stp:
                  enabled: false 7
              port:
                - name: eth1 8
    1
    Name of the policy.
    2
    Name of the interface.
    3
    Optional: Human-readable description of the interface.
    4
    The type of interface. This example creates a bridge.
    5
    The requested state for the interface after creation.
    6
    Disables IPv4 in this example.
    7
    Disables STP in this example.
    8
    The node NIC to which the bridge is attached.
5.3.2.2. Creating a Linux bridge NAD by using the web console

You can create a network attachment definition (NAD) to provide layer-2 networking to pods and virtual machines by using the OpenShift Container Platform web console.

A Linux bridge network attachment definition is the most efficient method for connecting a virtual machine to a VLAN.

Warning

Configuring IP address management (IPAM) in a network attachment definition for virtual machines is not supported.

Procedure

  1. In the web console, click NetworkingNetworkAttachmentDefinitions.
  2. Click Create Network Attachment Definition.

    Note

    The network attachment definition must be in the same namespace as the pod or virtual machine.

  3. Enter a unique Name and optional Description.
  4. Select CNV Linux bridge from the Network Type list.
  5. Enter the name of the bridge in the Bridge Name field.
  6. Optional: If the resource has VLAN IDs configured, enter the ID numbers in the VLAN Tag Number field.
  7. Optional: Select MAC Spoof Check to enable MAC spoof filtering. This feature provides security against a MAC spoofing attack by allowing only a single MAC address to exit the pod.
  8. Click Create.

5.3.3. Configuring a network for live migration

After you have configured a Linux bridge network, you can configure a dedicated network for live migration. A dedicated network minimizes the effects of network saturation on tenant workloads during live migration.

5.3.3.1. Configuring a dedicated secondary network for live migration

To configure a dedicated secondary network for live migration, you must first create a bridge network attachment definition (NAD) by using the CLI. Then, you add the name of the NetworkAttachmentDefinition object to the HyperConverged custom resource (CR).

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You logged in to the cluster as a user with the cluster-admin role.
  • Each node has at least two Network Interface Cards (NICs).
  • The NICs for live migration are connected to the same VLAN.

Procedure

  1. Create a NetworkAttachmentDefinition manifest according to the following example:

    Example configuration file

    apiVersion: "k8s.cni.cncf.io/v1"
    kind: NetworkAttachmentDefinition
    metadata:
      name: my-secondary-network 1
      namespace: openshift-cnv
    spec:
      config: '{
        "cniVersion": "0.3.1",
        "name": "migration-bridge",
        "type": "macvlan",
        "master": "eth1", 2
        "mode": "bridge",
        "ipam": {
          "type": "whereabouts", 3
          "range": "10.200.5.0/24" 4
        }
      }'

    1
    Specify the name of the NetworkAttachmentDefinition object.
    2
    Specify the name of the NIC to be used for live migration.
    3
    Specify the name of the CNI plugin that provides the network for the NAD.
    4
    Specify an IP address range for the secondary network. This range must not overlap the IP addresses of the main network.
  2. Open the HyperConverged CR in your default editor by running the following command:

    oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  3. Add the name of the NetworkAttachmentDefinition object to the spec.liveMigrationConfig stanza of the HyperConverged CR:

    Example HyperConverged manifest

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      liveMigrationConfig:
        completionTimeoutPerGiB: 800
        network: <network> 1
        parallelMigrationsPerCluster: 5
        parallelOutboundMigrationsPerNode: 2
        progressTimeout: 150
    # ...

    1
    Specify the name of the Multus NetworkAttachmentDefinition object to be used for live migrations.
  4. Save your changes and exit the editor. The virt-handler pods restart and connect to the secondary network.

Verification

  • When the node that the virtual machine runs on is placed into maintenance mode, the VM automatically migrates to another node in the cluster. You can verify that the migration occurred over the secondary network and not the default pod network by checking the target IP address in the virtual machine instance (VMI) metadata.

    $ oc get vmi <vmi_name> -o jsonpath='{.status.migrationState.targetNodeAddress}'
5.3.3.2. Selecting a dedicated network by using the web console

You can select a dedicated network for live migration by using the OpenShift Container Platform web console.

Prerequisites

  • You configured a Multus network for live migration.

Procedure

  1. Navigate to Virtualization > Overview in the OpenShift Container Platform web console.
  2. Click the Settings tab and then click Live migration.
  3. Select the network from the Live migration network list.

5.3.4. Configuring an SR-IOV network

After you install the SR-IOV Operator, you can configure an SR-IOV network.

5.3.4.1. Configuring SR-IOV network devices

The SR-IOV Network Operator adds the SriovNetworkNodePolicy.sriovnetwork.openshift.io CustomResourceDefinition to OpenShift Container Platform. You can configure an SR-IOV network device by creating a SriovNetworkNodePolicy custom resource (CR).

Note

When applying the configuration specified in a SriovNetworkNodePolicy object, the SR-IOV Operator might drain the nodes, and in some cases, reboot nodes. Reboot only happens in the following cases:

  • With Mellanox NICs (mlx5 driver) a node reboot happens every time the number of virtual functions (VFs) increase on a physical function (PF).
  • With Intel NICs, a reboot only happens if the kernel parameters do not include intel_iommu=on and iommu=pt.

It might take several minutes for a configuration change to apply.

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You have access to the cluster as a user with the cluster-admin role.
  • You have installed the SR-IOV Network Operator.
  • You have enough available nodes in your cluster to handle the evicted workload from drained nodes.
  • You have not selected any control plane nodes for SR-IOV network device configuration.

Procedure

  1. Create an SriovNetworkNodePolicy object, and then save the YAML in the <name>-sriov-node-network.yaml file. Replace <name> with the name for this configuration.

    apiVersion: sriovnetwork.openshift.io/v1
    kind: SriovNetworkNodePolicy
    metadata:
      name: <name> 1
      namespace: openshift-sriov-network-operator 2
    spec:
      resourceName: <sriov_resource_name> 3
      nodeSelector:
        feature.node.kubernetes.io/network-sriov.capable: "true" 4
      priority: <priority> 5
      mtu: <mtu> 6
      numVfs: <num> 7
      nicSelector: 8
        vendor: "<vendor_code>" 9
        deviceID: "<device_id>" 10
        pfNames: ["<pf_name>", ...] 11
        rootDevices: ["<pci_bus_id>", "..."] 12
      deviceType: vfio-pci 13
      isRdma: false 14
    1
    Specify a name for the CR object.
    2
    Specify the namespace where the SR-IOV Operator is installed.
    3
    Specify the resource name of the SR-IOV device plugin. You can create multiple SriovNetworkNodePolicy objects for a resource name.
    4
    Specify the node selector to select which nodes are configured. Only SR-IOV network devices on selected nodes are configured. The SR-IOV Container Network Interface (CNI) plugin and device plugin are deployed only on selected nodes.
    5
    Optional: Specify an integer value between 0 and 99. A smaller number gets higher priority, so a priority of 10 is higher than a priority of 99. The default value is 99.
    6
    Optional: Specify a value for the maximum transmission unit (MTU) of the virtual function. The maximum MTU value can vary for different NIC models.
    7
    Specify the number of the virtual functions (VF) to create for the SR-IOV physical network device. For an Intel network interface controller (NIC), the number of VFs cannot be larger than the total VFs supported by the device. For a Mellanox NIC, the number of VFs cannot be larger than 127.
    8
    The nicSelector mapping selects the Ethernet device for the Operator to configure. You do not need to specify values for all the parameters. It is recommended to identify the Ethernet adapter with enough precision to minimize the possibility of selecting an Ethernet device unintentionally. If you specify rootDevices, you must also specify a value for vendor, deviceID, or pfNames. If you specify both pfNames and rootDevices at the same time, ensure that they point to an identical device.
    9
    Optional: Specify the vendor hex code of the SR-IOV network device. The only allowed values are either 8086 or 15b3.
    10
    Optional: Specify the device hex code of SR-IOV network device. The only allowed values are 158b, 1015, 1017.
    11
    Optional: The parameter accepts an array of one or more physical function (PF) names for the Ethernet device.
    12
    The parameter accepts an array of one or more PCI bus addresses for the physical function of the Ethernet device. Provide the address in the following format: 0000:02:00.1.
    13
    The vfio-pci driver type is required for virtual functions in OpenShift Virtualization.
    14
    Optional: Specify whether to enable remote direct memory access (RDMA) mode. For a Mellanox card, set isRdma to false. The default value is false.
    Note

    If isRDMA flag is set to true, you can continue to use the RDMA enabled VF as a normal network device. A device can be used in either mode.

  2. Optional: Label the SR-IOV capable cluster nodes with SriovNetworkNodePolicy.Spec.NodeSelector if they are not already labeled. For more information about labeling nodes, see "Understanding how to update labels on nodes".
  3. Create the SriovNetworkNodePolicy object:

    $ oc create -f <name>-sriov-node-network.yaml

    where <name> specifies the name for this configuration.

    After applying the configuration update, all the pods in sriov-network-operator namespace transition to the Running status.

  4. To verify that the SR-IOV network device is configured, enter the following command. Replace <node_name> with the name of a node with the SR-IOV network device that you just configured.

    $ oc get sriovnetworknodestates -n openshift-sriov-network-operator <node_name> -o jsonpath='{.status.syncStatus}'

5.3.5. Enabling load balancer service creation by using the web console

You can enable the creation of load balancer services for a virtual machine (VM) by using the OpenShift Container Platform web console.

Prerequisites

  • You have configured a load balancer for the cluster.
  • You are logged in as a user with the cluster-admin role.

Procedure

  1. Navigate to VirtualizationOverview.
  2. On the Settings tab, click Cluster.
  3. Expand General settings and SSH configuration.
  4. Set SSH over LoadBalancer service to on.

5.4. Postinstallation storage configuration

The following storage configuration tasks are mandatory:

  • You must configure a default storage class for your cluster. Otherwise, the cluster cannot receive automated boot source updates.
  • You must configure storage profiles if your storage provider is not recognized by CDI. A storage profile provides recommended storage settings based on the associated storage class.

Optional: You can configure local storage by using the hostpath provisioner (HPP).

See the storage configuration overview for more options, including configuring the Containerized Data Importer (CDI), data volumes, and automatic boot source updates.

5.4.1. Configuring local storage by using the HPP

When you install the OpenShift Virtualization Operator, the Hostpath Provisioner (HPP) Operator is automatically installed. The HPP Operator creates the HPP provisioner.

The HPP is a local storage provisioner designed for OpenShift Virtualization. To use the HPP, you must create an HPP custom resource (CR).

Important

HPP storage pools must not be in the same partition as the operating system. Otherwise, the storage pools might fill the operating system partition. If the operating system partition is full, performance can be effected or the node can become unstable or unusable.

5.4.1.1. Creating a storage class for the CSI driver with the storagePools stanza

To use the hostpath provisioner (HPP) you must create an associated storage class for the Container Storage Interface (CSI) driver.

When you create a storage class, you set parameters that affect the dynamic provisioning of persistent volumes (PVs) that belong to that storage class. You cannot update a StorageClass object’s parameters after you create it.

Note

Virtual machines use data volumes that are based on local PVs. Local PVs are bound to specific nodes. While a disk image is prepared for consumption by the virtual machine, it is possible that the virtual machine cannot be scheduled to the node where the local storage PV was previously pinned.

To solve this problem, use the Kubernetes pod scheduler to bind the persistent volume claim (PVC) to a PV on the correct node. By using the StorageClass value with volumeBindingMode parameter set to WaitForFirstConsumer, the binding and provisioning of the PV is delayed until a pod is created using the PVC.

Procedure

  1. Create a storageclass_csi.yaml file to define the storage class:

    apiVersion: storage.k8s.io/v1
    kind: StorageClass
    metadata:
      name: hostpath-csi
    provisioner: kubevirt.io.hostpath-provisioner
    reclaimPolicy: Delete 1
    volumeBindingMode: WaitForFirstConsumer 2
    parameters:
      storagePool: my-storage-pool 3
    1
    The two possible reclaimPolicy values are Delete and Retain. If you do not specify a value, the default value is Delete.
    2
    The volumeBindingMode parameter determines when dynamic provisioning and volume binding occur. Specify WaitForFirstConsumer to delay the binding and provisioning of a persistent volume (PV) until after a pod that uses the persistent volume claim (PVC) is created. This ensures that the PV meets the pod’s scheduling requirements.
    3
    Specify the name of the storage pool defined in the HPP CR.
  2. Save the file and exit.
  3. Create the StorageClass object by running the following command:

    $ oc create -f storageclass_csi.yaml

5.5. Configuring higher VM workload density

You can increase the number of virtual machines (VMs) on nodes by overcommitting memory (RAM). Increasing VM workload density can be useful in the following situations:

  • You have many similar workloads.
  • You have underused workloads.
Note

Memory overcommitment can lower workload performance on a highly utilized system.

5.5.1. Using wasp-agent to increase VM workload density

The wasp-agent component facilitates memory overcommitment by assigning swap resources to worker nodes. It also manages pod evictions when nodes are at risk due to high swap I/O traffic or high utilization.

Important

Swap resources can be only assigned to virtual machine workloads (VM pods) of the Burstable Quality of Service (QoS) class. VM pods of the Guaranteed QoS class and pods of any QoS class that do not belong to VMs cannot swap resources.

For descriptions of QoS classes, see Configure Quality of Service for Pods (Kubernetes documentation).

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • You are logged into the cluster with the cluster-admin role.
  • A memory overcommit ratio is defined.
  • The node belongs to a worker pool.
Note

The wasp-agent component deploys an Open Container Initiative (OCI) hook to enable swap usage for containers on the node level. The low-level nature requires the DaemonSet object to be privileged.

Procedure

  1. Configure the kubelet service to permit swap usage:

    1. Create or edit a KubeletConfig file with the parameters shown in the following example:

      Example of a KubeletConfig file

      apiVersion: machineconfiguration.openshift.io/v1
      kind: KubeletConfig
      metadata:
        name: custom-config
      spec:
        machineConfigPoolSelector:
          matchLabels:
            pools.operator.machineconfiguration.openshift.io/worker: ''  # MCP
            #machine.openshift.io/cluster-api-machine-role: worker # machine
            #node-role.kubernetes.io/worker: '' # node
        kubeletConfig:
          failSwapOn: false

    2. Wait for the worker nodes to sync with the new configuration by running the following command:

      $ oc wait mcp worker --for condition=Updated=True --timeout=-1s
  2. Provision swap by creating a MachineConfig object. For example:

    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    metadata:
      labels:
        machineconfiguration.openshift.io/role: worker
      name: 90-worker-swap
    spec:
      config:
        ignition:
          version: 3.4.0
        systemd:
          units:
            - contents: |
                [Unit]
                Description=Provision and enable swap
                ConditionFirstBoot=no
    
                [Service]
                Type=oneshot
                Environment=SWAP_SIZE_MB=5000
                ExecStart=/bin/sh -c "sudo dd if=/dev/zero of=/var/tmp/swapfile count=${SWAP_SIZE_MB} bs=1M && \
                sudo chmod 600 /var/tmp/swapfile && \
                sudo mkswap /var/tmp/swapfile && \
                sudo swapon /var/tmp/swapfile && \
                free -h && \
                sudo systemctl set-property --runtime system.slice MemorySwapMax=0 IODeviceLatencyTargetSec=\"/ 50ms\""
    
                [Install]
                RequiredBy=kubelet-dependencies.target
              enabled: true
              name: swap-provision.service

    To have enough swap space for the worst-case scenario, make sure to have at least as much swap space provisioned as overcommitted RAM. Calculate the amount of swap space to be provisioned on a node by using the following formula:

    NODE_SWAP_SPACE = NODE_RAM * (MEMORY_OVER_COMMIT_PERCENT / 100% - 1)

    Example

    NODE_SWAP_SPACE = 16 GB * (150% / 100% - 1)
                   = 16 GB * (1.5 - 1)
                   = 16 GB * (0.5)
                   =  8 GB

  3. Create a privileged service account by running the following commands:

    $ oc adm new-project wasp
    $ oc create sa -n wasp wasp
    $ oc create clusterrolebinding wasp --clusterrole=cluster-admin --serviceaccount=wasp:wasp
    $ oc adm policy add-scc-to-user -n wasp privileged -z wasp
  4. Wait for the worker nodes to sync with the new configuration by running the following command:

    $ oc wait mcp worker --for condition=Updated=True --timeout=-1s
  5. Determine the pull URL for the wasp agent image by running the following command:

    $ oc get csv -n openshift-cnv -l=operators.coreos.com/kubevirt-hyperconverged.openshift-cnv -ojson | jq '.items[0].spec.relatedImages[] | select(.name|test(".*wasp-agent.*")) | .image'
  6. Deploy wasp-agent by creating a DaemonSet object as shown in the following example:

    kind: DaemonSet
    apiVersion: apps/v1
    metadata:
      name: wasp-agent
      namespace: wasp
      labels:
        app: wasp
        tier: node
    spec:
      selector:
        matchLabels:
          name: wasp
      template:
        metadata:
          annotations:
            description: >-
              Configures swap for workloads
          labels:
            name: wasp
        spec:
          containers:
            - env:
                - name: SWAP_UTILIZATION_THRESHOLD_FACTOR
                  value: "0.8"
                - name: MAX_AVERAGE_SWAP_IN_PAGES_PER_SECOND
                  value: "1000"
                - name: MAX_AVERAGE_SWAP_OUT_PAGES_PER_SECOND
                  value: "1000"
                - name: AVERAGE_WINDOW_SIZE_SECONDS
                  value: "30"
                - name: VERBOSITY
                  value: "1"
                - name: FSROOT
                  value: /host
                - name: NODE_NAME
                  valueFrom:
                    fieldRef:
                      fieldPath: spec.nodeName
              image: >-
                quay.io/openshift-virtualization/wasp-agent:v4.17 1
              imagePullPolicy: Always
              name: wasp-agent
              resources:
                requests:
                  cpu: 100m
                  memory: 50M
              securityContext:
                privileged: true
              volumeMounts:
                - mountPath: /host
                  name: host
                - mountPath: /rootfs
                  name: rootfs
          hostPID: true
          hostUsers: true
          priorityClassName: system-node-critical
          serviceAccountName: wasp
          terminationGracePeriodSeconds: 5
          volumes:
            - hostPath:
                path: /
              name: host
            - hostPath:
                path: /
              name: rootfs
      updateStrategy:
        type: RollingUpdate
        rollingUpdate:
          maxUnavailable: 10%
          maxSurge: 0
    1
    Replace the image value with the image URL from the previous step.
  7. Deploy alerting rules by creating a PrometheusRule object. For example:

    apiVersion: monitoring.coreos.com/v1
    kind: PrometheusRule
    metadata:
      labels:
        tier: node
        wasp.io: ""
      name: wasp-rules
      namespace: wasp
    spec:
      groups:
        - name: alerts.rules
          rules:
            - alert: NodeHighSwapActivity
              annotations:
                description: High swap activity detected at {{ $labels.instance }}. The rate
                  of swap out and swap in exceeds 200 in both operations in the last minute.
                  This could indicate memory pressure and may affect system performance.
                runbook_url: https://github.com/openshift-virtualization/wasp-agent/tree/main/docs/runbooks/NodeHighSwapActivity.md
                summary: High swap activity detected at {{ $labels.instance }}.
              expr: rate(node_vmstat_pswpout[1m]) > 200 and rate(node_vmstat_pswpin[1m]) >
                200
              for: 1m
              labels:
                kubernetes_operator_component: kubevirt
                kubernetes_operator_part_of: kubevirt
                operator_health_impact: warning
                severity: warning
  8. Add the cluster-monitoring label to the wasp namespace by running the following command:

    $ oc label namespace wasp openshift.io/cluster-monitoring="true"
  9. Enable memory overcommitment in OpenShift Virtualization by using the web console or the CLI.

    Web console

    1. In the OpenShift Container Platform web console, go to VirtualizationOverviewSettingsGeneral settingsMemory density.
    2. Set Enable memory density to on.

    CLI

    • Run the following command:

      $ oc patch --type=merge \
        -f <../manifests/openshift/hco-set-memory-overcommit.yaml> \
        --patch-file <../manifests/openshift/hco-set-memory-overcommit.yaml>

Verification

  1. To verify the deployment of wasp-agent, run the following command:

    $ oc rollout status ds wasp-agent -n wasp

    If the deployment is successful, the following message is displayed:

    Example output

    daemon set "wasp-agent" successfully rolled out

  2. To verify that swap is correctly provisioned, complete the following steps:

    1. View a list of worker nodes by running the following command:

      $ oc get nodes -l node-role.kubernetes.io/worker
    2. Select a node from the list and display its memory usage by running the following command:

      $ oc debug node/<selected_node> -- free -m 1
      1
      Replace <selected_node> with the node name.

      If swap is provisioned, an amount greater than zero is displayed in the Swap: row.

      Table 5.1. Example output
       

      total

      used

      free

      shared

      buff/cache

      available

      Mem:

      31846

      23155

      1044

      6014

      14483

      8690

      Swap:

      8191

      2337

      5854

         
  3. Verify the OpenShift Virtualization memory overcommitment configuration by running the following command:

    $ oc get -n openshift-cnv HyperConverged kubevirt-hyperconverged -o jsonpath="{.spec.higherWorkloadDensity.memoryOvercommitPercentage}"

    Example output

    150

    The returned value must match the value you had previously configured.

5.5.2. Pod eviction conditions used by wasp-agent

The wasp agent manages pod eviction when the system is heavily loaded and nodes are at risk. Eviction is triggered if one of the following conditions is met:

High swap I/O traffic

This condition is met when swap-related I/O traffic is excessively high.

Condition

averageSwapInPerSecond > maxAverageSwapInPagesPerSecond
&&
averageSwapOutPerSecond > maxAverageSwapOutPagesPerSecond

By default, maxAverageSwapInPagesPerSecond and maxAverageSwapOutPagesPerSecond are set to 1000 pages. The default time interval for calculating the average is 30 seconds.

High swap utilization

This condition is met when swap utilization is excessively high, causing the current virtual memory usage to exceed the factored threshold. The NODE_SWAP_SPACE setting in your MachineConfig object can impact this condition.

Condition

nodeWorkingSet + nodeSwapUsage < totalNodeMemory + totalSwapMemory × thresholdFactor

5.5.2.1. Environment variables

You can use the following environment variables to adjust the values used to calculate eviction conditions:

Environment variable

Function

MAX_AVERAGE_SWAP_IN_PAGES_PER_SECOND

Sets the value of maxAverageSwapInPagesPerSecond.

MAX_AVERAGE_SWAP_OUT_PAGES_PER_SECOND

Sets the value of maxAverageSwapOutPagesPerSecond.

SWAP_UTILIZATION_THRESHOLD_FACTOR

Sets the thresholdFactor value used to calculate high swap utilization.

AVERAGE_WINDOW_SIZE_SECONDS

Sets the time interval for calculating the average swap usage.

Chapter 6. Updating

6.1. Updating OpenShift Virtualization

Learn how Operator Lifecycle Manager (OLM) delivers z-stream and minor version updates for OpenShift Virtualization.

6.1.1. OpenShift Virtualization on RHEL 9

OpenShift Virtualization 4.17 is based on Red Hat Enterprise Linux (RHEL) 9. You can update to OpenShift Virtualization 4.17 from a version that was based on RHEL 8 by following the standard OpenShift Virtualization update procedure. No additional steps are required.

As in previous versions, you can perform the update without disrupting running workloads. OpenShift Virtualization 4.17 supports live migration from RHEL 8 nodes to RHEL 9 nodes.

6.1.1.1. RHEL 9 machine type

All VM templates that are included with OpenShift Virtualization now use the RHEL 9 machine type by default: machineType: pc-q35-rhel9.<y>.0, where <y> is a single digit corresponding to the latest minor version of RHEL 9. For example, the value pc-q35-rhel9.2.0 is used for RHEL 9.2.

Updating OpenShift Virtualization does not change the machineType value of any existing VMs. These VMs continue to function as they did before the update. You can optionally change a VM’s machine type so that it can benefit from RHEL 9 improvements.

Important

Before you change a VM’s machineType value, you must shut down the VM.

6.1.2. About updating OpenShift Virtualization

  • Operator Lifecycle Manager (OLM) manages the lifecycle of the OpenShift Virtualization Operator. The Marketplace Operator, which is deployed during OpenShift Container Platform installation, makes external Operators available to your cluster.
  • OLM provides z-stream and minor version updates for OpenShift Virtualization. Minor version updates become available when you update OpenShift Container Platform to the next minor version. You cannot update OpenShift Virtualization to the next minor version without first updating OpenShift Container Platform.
  • OpenShift Virtualization subscriptions use a single update channel that is named stable. The stable channel ensures that your OpenShift Virtualization and OpenShift Container Platform versions are compatible.
  • If your subscription’s approval strategy is set to Automatic, the update process starts as soon as a new version of the Operator is available in the stable channel. It is highly recommended to use the Automatic approval strategy to maintain a supportable environment. Each minor version of OpenShift Virtualization is only supported if you run the corresponding OpenShift Container Platform version. For example, you must run OpenShift Virtualization 4.17 on OpenShift Container Platform 4.17.

    • Though it is possible to select the Manual approval strategy, this is not recommended because it risks the supportability and functionality of your cluster. With the Manual approval strategy, you must manually approve every pending update. If OpenShift Container Platform and OpenShift Virtualization updates are out of sync, your cluster becomes unsupported.
  • The amount of time an update takes to complete depends on your network connection. Most automatic updates complete within fifteen minutes.
  • Updating OpenShift Virtualization does not interrupt network connections.
  • Data volumes and their associated persistent volume claims are preserved during update.
Important

If you have virtual machines running that use hostpath provisioner storage, they cannot be live migrated and might block an OpenShift Container Platform cluster update.

As a workaround, you can reconfigure the virtual machines so that they can be powered off automatically during a cluster update. Set the evictionStrategy field to None and the runStrategy field to Always.

6.1.2.1. About workload updates

When you update OpenShift Virtualization, virtual machine workloads, including libvirt, virt-launcher, and qemu, update automatically if they support live migration.

Note

Each virtual machine has a virt-launcher pod that runs the virtual machine instance (VMI). The virt-launcher pod runs an instance of libvirt, which is used to manage the virtual machine (VM) process.

You can configure how workloads are updated by editing the spec.workloadUpdateStrategy stanza of the HyperConverged custom resource (CR). There are two available workload update methods: LiveMigrate and Evict.

Because the Evict method shuts down VMI pods, only the LiveMigrate update strategy is enabled by default.

When LiveMigrate is the only update strategy enabled:

  • VMIs that support live migration are migrated during the update process. The VM guest moves into a new pod with the updated components enabled.
  • VMIs that do not support live migration are not disrupted or updated.

    • If a VMI has the LiveMigrate eviction strategy but does not support live migration, it is not updated.

If you enable both LiveMigrate and Evict:

  • VMIs that support live migration use the LiveMigrate update strategy.
  • VMIs that do not support live migration use the Evict update strategy. If a VMI is controlled by a VirtualMachine object that has runStrategy: Always set, a new VMI is created in a new pod with updated components.
Migration attempts and timeouts

When updating workloads, live migration fails if a pod is in the Pending state for the following periods:

5 minutes
If the pod is pending because it is Unschedulable.
15 minutes
If the pod is stuck in the pending state for any reason.

When a VMI fails to migrate, the virt-controller tries to migrate it again. It repeats this process until all migratable VMIs are running on new virt-launcher pods. If a VMI is improperly configured, however, these attempts can repeat indefinitely.

Note

Each attempt corresponds to a migration object. Only the five most recent attempts are held in a buffer. This prevents migration objects from accumulating on the system while retaining information for debugging.

6.1.2.2. About Control Plane Only updates

Every even-numbered minor version of OpenShift Container Platform, including 4.10 and 4.12, is an Extended Update Support (EUS) version. However, because Kubernetes design mandates serial minor version updates, you cannot directly update from one EUS version to the next.

After you update from the source EUS version to the next odd-numbered minor version, you must sequentially update OpenShift Virtualization to all z-stream releases of that minor version that are on your update path. When you have upgraded to the latest applicable z-stream version, you can then update OpenShift Container Platform to the target EUS minor version.

When the OpenShift Container Platform update succeeds, the corresponding update for OpenShift Virtualization becomes available. You can now update OpenShift Virtualization to the target EUS version.

6.1.2.2.1. Preparing to update

Before beginning a Control Plane Only update, you must:

  • Pause worker nodes' machine config pools before you start a Control Plane Only update so that the workers are not rebooted twice.
  • Disable automatic workload updates before you begin the update process. This is to prevent OpenShift Virtualization from migrating or evicting your virtual machines (VMs) until you update to your target EUS version.
Note

By default, OpenShift Virtualization automatically updates workloads, such as the virt-launcher pod, when you update the OpenShift Virtualization Operator. You can configure this behavior in the spec.workloadUpdateStrategy stanza of the HyperConverged custom resource.

Learn more about Performing a Control Plane Only update.

6.1.3. Preventing workload updates during a Control Plane Only update

When you update from one Extended Update Support (EUS) version to the next, you must manually disable automatic workload updates to prevent OpenShift Virtualization from migrating or evicting workloads during the update process.

Prerequisites

  • You are running an EUS version of OpenShift Container Platform and want to update to the next EUS version. You have not yet updated to the odd-numbered version in between.
  • You read "Preparing to perform a Control Plane Only update" and learned the caveats and requirements that pertain to your OpenShift Container Platform cluster.
  • You paused the worker nodes' machine config pools as directed by the OpenShift Container Platform documentation.
  • It is recommended that you use the default Automatic approval strategy. If you use the Manual approval strategy, you must approve all pending updates in the web console. For more details, refer to the "Manually approving a pending Operator update" section.

Procedure

  1. Run the following command and record the workloadUpdateMethods configuration:

    $ oc get kv kubevirt-kubevirt-hyperconverged \
      -n openshift-cnv -o jsonpath='{.spec.workloadUpdateStrategy.workloadUpdateMethods}'
  2. Turn off all workload update methods by running the following command:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
      --type json -p '[{"op":"replace","path":"/spec/workloadUpdateStrategy/workloadUpdateMethods", "value":[]}]'

    Example output

    hyperconverged.hco.kubevirt.io/kubevirt-hyperconverged patched

  3. Ensure that the HyperConverged Operator is Upgradeable before you continue. Enter the following command and monitor the output:

    $ oc get hyperconverged kubevirt-hyperconverged -n openshift-cnv -o json | jq ".status.conditions"

    Example 6.1. Example output

    [
      {
        "lastTransitionTime": "2022-12-09T16:29:11Z",
        "message": "Reconcile completed successfully",
        "observedGeneration": 3,
        "reason": "ReconcileCompleted",
        "status": "True",
        "type": "ReconcileComplete"
      },
      {
        "lastTransitionTime": "2022-12-09T20:30:10Z",
        "message": "Reconcile completed successfully",
        "observedGeneration": 3,
        "reason": "ReconcileCompleted",
        "status": "True",
        "type": "Available"
      },
      {
        "lastTransitionTime": "2022-12-09T20:30:10Z",
        "message": "Reconcile completed successfully",
        "observedGeneration": 3,
        "reason": "ReconcileCompleted",
        "status": "False",
        "type": "Progressing"
      },
      {
        "lastTransitionTime": "2022-12-09T16:39:11Z",
        "message": "Reconcile completed successfully",
        "observedGeneration": 3,
        "reason": "ReconcileCompleted",
        "status": "False",
        "type": "Degraded"
      },
      {
        "lastTransitionTime": "2022-12-09T20:30:10Z",
        "message": "Reconcile completed successfully",
        "observedGeneration": 3,
        "reason": "ReconcileCompleted",
        "status": "True",
        "type": "Upgradeable" 1
      }
    ]
    1
    The OpenShift Virtualization Operator has the Upgradeable status.
  4. Manually update your cluster from the source EUS version to the next minor version of OpenShift Container Platform:

    $ oc adm upgrade

    Verification

    • Check the current version by running the following command:

      $ oc get clusterversion
      Note

      Updating OpenShift Container Platform to the next version is a prerequisite for updating OpenShift Virtualization. For more details, refer to the "Updating clusters" section of the OpenShift Container Platform documentation.

  5. Update OpenShift Virtualization.

    • With the default Automatic approval strategy, OpenShift Virtualization automatically updates to the corresponding version after you update OpenShift Container Platform.
    • If you use the Manual approval strategy, approve the pending updates by using the web console.
  6. Monitor the OpenShift Virtualization update by running the following command:

    $ oc get csv -n openshift-cnv
  7. Update OpenShift Virtualization to every z-stream version that is available for the non-EUS minor version, monitoring each update by running the command shown in the previous step.
  8. Confirm that OpenShift Virtualization successfully updated to the latest z-stream release of the non-EUS version by running the following command:

    $ oc get hyperconverged kubevirt-hyperconverged -n openshift-cnv -o json | jq ".status.versions"

    Example output

    [
      {
        "name": "operator",
        "version": "4.17.0"
      }
    ]

  9. Wait until the HyperConverged Operator has the Upgradeable status before you perform the next update. Enter the following command and monitor the output:

    $ oc get hyperconverged kubevirt-hyperconverged -n openshift-cnv -o json | jq ".status.conditions"
  10. Update OpenShift Container Platform to the target EUS version.
  11. Confirm that the update succeeded by checking the cluster version:

    $ oc get clusterversion
  12. Update OpenShift Virtualization to the target EUS version.

    • With the default Automatic approval strategy, OpenShift Virtualization automatically updates to the corresponding version after you update OpenShift Container Platform.
    • If you use the Manual approval strategy, approve the pending updates by using the web console.
  13. Monitor the OpenShift Virtualization update by running the following command:

    $ oc get csv -n openshift-cnv

    The update completes when the VERSION field matches the target EUS version and the PHASE field reads Succeeded.

  14. Restore the workloadUpdateMethods configuration that you recorded from step 1 with the following command:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv --type json -p \
      "[{\"op\":\"add\",\"path\":\"/spec/workloadUpdateStrategy/workloadUpdateMethods\", \"value\":{WorkloadUpdateMethodConfig}}]"

    Example output

    hyperconverged.hco.kubevirt.io/kubevirt-hyperconverged patched

    Verification

    • Check the status of VM migration by running the following command:

      $ oc get vmim -A

Next steps

  • You can now unpause the worker nodes' machine config pools.

6.1.4. Configuring workload update methods

You can configure workload update methods by editing the HyperConverged custom resource (CR).

Prerequisites

  • To use live migration as an update method, you must first enable live migration in the cluster.

    Note

    If a VirtualMachineInstance CR contains evictionStrategy: LiveMigrate and the virtual machine instance (VMI) does not support live migration, the VMI will not update.

Procedure

  1. To open the HyperConverged CR in your default editor, run the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Edit the workloadUpdateStrategy stanza of the HyperConverged CR. For example:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      workloadUpdateStrategy:
        workloadUpdateMethods: 1
        - LiveMigrate 2
        - Evict 3
        batchEvictionSize: 10 4
        batchEvictionInterval: "1m0s" 5
    # ...
    1
    The methods that can be used to perform automated workload updates. The available values are LiveMigrate and Evict. If you enable both options as shown in this example, updates use LiveMigrate for VMIs that support live migration and Evict for any VMIs that do not support live migration. To disable automatic workload updates, you can either remove the workloadUpdateStrategy stanza or set workloadUpdateMethods: [] to leave the array empty.
    2
    The least disruptive update method. VMIs that support live migration are updated by migrating the virtual machine (VM) guest into a new pod with the updated components enabled. If LiveMigrate is the only workload update method listed, VMIs that do not support live migration are not disrupted or updated.
    3
    A disruptive method that shuts down VMI pods during upgrade. Evict is the only update method available if live migration is not enabled in the cluster. If a VMI is controlled by a VirtualMachine object that has runStrategy: Always configured, a new VMI is created in a new pod with updated components.
    4
    The number of VMIs that can be forced to be updated at a time by using the Evict method. This does not apply to the LiveMigrate method.
    5
    The interval to wait before evicting the next batch of workloads. This does not apply to the LiveMigrate method.
    Note

    You can configure live migration limits and timeouts by editing the spec.liveMigrationConfig stanza of the HyperConverged CR.

  3. To apply your changes, save and exit the editor.

6.1.5. Approving pending Operator updates

6.1.5.1. Manually approving a pending Operator update

If an installed Operator has the approval strategy in its subscription set to Manual, when new updates are released in its current update channel, the update must be manually approved before installation can begin.

Prerequisites

  • An Operator previously installed using Operator Lifecycle Manager (OLM).

Procedure

  1. In the Administrator perspective of the OpenShift Container Platform web console, navigate to Operators → Installed Operators.
  2. Operators that have a pending update display a status with Upgrade available. Click the name of the Operator you want to update.
  3. Click the Subscription tab. Any updates requiring approval are displayed next to Upgrade status. For example, it might display 1 requires approval.
  4. Click 1 requires approval, then click Preview Install Plan.
  5. Review the resources that are listed as available for update. When satisfied, click Approve.
  6. Navigate back to the Operators → Installed Operators page to monitor the progress of the update. When complete, the status changes to Succeeded and Up to date.

6.1.6. Monitoring update status

6.1.6.1. Monitoring OpenShift Virtualization upgrade status

To monitor the status of a OpenShift Virtualization Operator upgrade, watch the cluster service version (CSV) PHASE. You can also monitor the CSV conditions in the web console or by running the command provided here.

Note

The PHASE and conditions values are approximations that are based on available information.

Prerequisites

  • Log in to the cluster as a user with the cluster-admin role.
  • Install the OpenShift CLI (oc).

Procedure

  1. Run the following command:

    $ oc get csv -n openshift-cnv
  2. Review the output, checking the PHASE field. For example:

    Example output

    VERSION  REPLACES                                        PHASE
    4.9.0    kubevirt-hyperconverged-operator.v4.8.2         Installing
    4.9.0    kubevirt-hyperconverged-operator.v4.9.0         Replacing

  3. Optional: Monitor the aggregated status of all OpenShift Virtualization component conditions by running the following command:

    $ oc get hyperconverged kubevirt-hyperconverged -n openshift-cnv \
      -o=jsonpath='{range .status.conditions[*]}{.type}{"\t"}{.status}{"\t"}{.message}{"\n"}{end}'

    A successful upgrade results in the following output:

    Example output

    ReconcileComplete  True  Reconcile completed successfully
    Available          True  Reconcile completed successfully
    Progressing        False Reconcile completed successfully
    Degraded           False Reconcile completed successfully
    Upgradeable        True  Reconcile completed successfully

6.1.6.2. Viewing outdated OpenShift Virtualization workloads

You can view a list of outdated workloads by using the CLI.

Note

If there are outdated virtualization pods in your cluster, the OutdatedVirtualMachineInstanceWorkloads alert fires.

Procedure

  • To view a list of outdated virtual machine instances (VMIs), run the following command:

    $ oc get vmi -l kubevirt.io/outdatedLauncherImage --all-namespaces
Note

Configure workload updates to ensure that VMIs update automatically.

6.1.7. Additional resources

Chapter 7. Virtual machines

7.1. Creating VMs from Red Hat images

7.1.1. Creating virtual machines from Red Hat images overview

Red Hat images are golden images. They are published as container disks in a secure registry. The Containerized Data Importer (CDI) polls and imports the container disks into your cluster and stores them in the openshift-virtualization-os-images project as snapshots or persistent volume claims (PVCs).

Red Hat images are automatically updated. You can disable and re-enable automatic updates for these images. See Managing Red Hat boot source updates.

Cluster administrators can enable automatic subscription for Red Hat Enterprise Linux (RHEL) virtual machines in the OpenShift Virtualization web console.

You can create virtual machines (VMs) from operating system images provided by Red Hat by using one of the following methods:

Important

Do not create VMs in the default openshift-* namespaces. Instead, create a new namespace or use an existing namespace without the openshift prefix.

7.1.1.1. About golden images

A golden image is a preconfigured snapshot of a virtual machine (VM) that you can use as a resource to deploy new VMs. For example, you can use golden images to provision the same system environment consistently and deploy systems more quickly and efficiently.

7.1.1.1.1. How do golden images work?

Golden images are created by installing and configuring an operating system and software applications on a reference machine or virtual machine. This includes setting up the system, installing required drivers, applying patches and updates, and configuring specific options and preferences.

After the golden image is created, it is saved as a template or image file that can be replicated and deployed across multiple clusters. The golden image can be updated by its maintainer periodically to incorporate necessary software updates and patches, ensuring that the image remains up to date and secure, and newly created VMs are based on this updated image.

7.1.1.1.2. Red Hat implementation of golden images

Red Hat publishes golden images as container disks in the registry for versions of Red Hat Enterprise Linux (RHEL). Container disks are virtual machine images that are stored as a container image in a container image registry. Any published image will automatically be made available in connected clusters after the installation of OpenShift Virtualization. After the images are available in a cluster, they are ready to use to create VMs.

7.1.1.2. About VM boot sources

Virtual machines (VMs) consist of a VM definition and one or more disks that are backed by data volumes. VM templates enable you to create VMs using predefined specifications.

Every template requires a boot source, which is a fully configured disk image including configured drivers. Each template contains a VM definition with a pointer to the boot source. Each boot source has a predefined name and namespace. For some operating systems, a boot source is automatically provided. If it is not provided, then an administrator must prepare a custom boot source.

Provided boot sources are updated automatically to the latest version of the operating system. For auto-updated boot sources, persistent volume claims (PVCs) and volume snapshots are created with the cluster’s default storage class. If you select a different default storage class after configuration, you must delete the existing boot sources in the cluster namespace that are configured with the previous default storage class.

7.1.2. Creating virtual machines from instance types

You can simplify virtual machine (VM) creation by using instance types, whether you use the OpenShift Container Platform web console or the CLI to create VMs.

7.1.2.1. About instance types

An instance type is a reusable object where you can define resources and characteristics to apply to new VMs. You can define custom instance types or use the variety that are included when you install OpenShift Virtualization.

To create a new instance type, you must first create a manifest, either manually or by using the virtctl CLI tool. You then create the instance type object by applying the manifest to your cluster.

OpenShift Virtualization provides two CRDs for configuring instance types:

  • A namespaced object: VirtualMachineInstancetype
  • A cluster-wide object: VirtualMachineClusterInstancetype

These objects use the same VirtualMachineInstancetypeSpec.

7.1.2.1.1. Required attributes

When you configure an instance type, you must define the cpu and memory attributes. Other attributes are optional.

Note

When you create a VM from an instance type, you cannot override any parameters defined in the instance type.

Because instance types require defined CPU and memory attributes, OpenShift Virtualization always rejects additional requests for these resources when creating a VM from an instance type.

You can manually create an instance type manifest. For example:

Example YAML file with required fields

apiVersion: instancetype.kubevirt.io/v1beta1
kind: VirtualMachineInstancetype
metadata:
  name: example-instancetype
spec:
  cpu:
    guest: 1 1
  memory:
    guest: 128Mi 2

1
Required. Specifies the number of vCPUs to allocate to the guest.
2
Required. Specifies an amount of memory to allocate to the guest.

You can create an instance type manifest by using the virtctl CLI utility. For example:

Example virtctl command with required fields

$ virtctl create instancetype --cpu 2 --memory 256Mi

where:

--cpu <value>
Specifies the number of vCPUs to allocate to the guest. Required.
--memory <value>
Specifies an amount of memory to allocate to the guest. Required.
Tip

You can immediately create the object from the new manifest by running the following command:

$ virtctl create instancetype --cpu 2 --memory 256Mi | oc apply -f -
7.1.2.1.2. Optional attributes

In addition to the required cpu and memory attributes, you can include the following optional attributes in the VirtualMachineInstancetypeSpec:

annotations
List annotations to apply to the VM.
gpus
List vGPUs for passthrough.
hostDevices
List host devices for passthrough.
ioThreadsPolicy
Define an IO threads policy for managing dedicated disk access.
launchSecurity
Configure Secure Encrypted Virtualization (SEV).
nodeSelector
Specify node selectors to control the nodes where this VM is scheduled.
schedulerName
Define a custom scheduler to use for this VM instead of the default scheduler.
7.1.2.2. Pre-defined instance types

OpenShift Virtualization includes a set of pre-defined instance types called common-instancetypes. Some are specialized for specific workloads and others are workload-agnostic.

These instance type resources are named according to their series, version, and size. The size value follows the . delimiter and ranges from nano to 8xlarge.

Table 7.1. common-instancetypes series comparison
Use caseSeriesCharacteristicsvCPU to memory ratioExample resource

Universal

U

  • Burstable CPU performance

1:4

u1.medium
  • 1 vCPUs
  • 4 Gi memory

Overcommitted

O

  • Overcommitted memory
  • Burstable CPU performance

1:4

o1.small
  • 1 vCPU
  • 2Gi memory

Compute-exclusive

CX

  • Hugepages
  • Dedicated CPU
  • Isolated emulator threads
  • vNUMA

1:2

cx1.2xlarge
  • 8 vCPUs
  • 16Gi memory

NVIDIA GPU

GN

  • For VMs that use GPUs provided by the NVIDIA GPU Operator
  • Has predefined GPUs
  • Burstable CPU performance

1:4

gn1.8xlarge
  • 32 vCPUs
  • 128Gi memory

Memory-intensive

M

  • Hugepages
  • Burstable CPU performance

1:8

m1.large
  • 2 vCPUs
  • 16Gi memory

Network-intensive

N

  • Hugepages
  • Dedicated CPU
  • Isolated emulator threads
  • Requires nodes capable of running DPDK workloads

1:2

n1.medium
  • 4 vCPUs
  • 4Gi memory
7.1.2.3. Creating manifests by using the virtctl tool

You can use the virtctl CLI utility to simplify creating manifests for VMs, VM instance types, and VM preferences. For more information, see VM manifest creation commands.

If you have a VirtualMachine manifest, you can create a VM from the command line.

7.1.2.4. Creating a VM from an instance type by using the web console

You can create a virtual machine (VM) from an instance type by using the OpenShift Container Platform web console. You can also use the web console to create a VM by copying an existing snapshot or to clone a VM.

You can create a VM from a list of available bootable volumes. You can add Linux- or Windows-based volumes to the list.

Procedure

  1. In the web console, navigate to VirtualizationCatalog.

    The InstanceTypes tab opens by default.

  2. Select either of the following options:

    • Select a suitable bootable volume from the list. If the list is truncated, click the Show all button to display the entire list.

      Note

      The bootable volume table lists only those volumes in the openshift-virtualization-os-images namespace that have the instancetype.kubevirt.io/default-preference label.

      • Optional: Click the star icon to designate a bootable volume as a favorite. Starred bootable volumes appear first in the volume list.
    • Click Add volume to upload a new volume or to use an existing persistent volume claim (PVC), a volume snapshot, or a containerDisk volume. Click Save.

      Logos of operating systems that are not available in the cluster are shown at the bottom of the list. You can add a volume for the required operating system by clicking the Add volume link.

      In addition, there is a link to the Create a Windows boot source quick start. The same link appears in a popover if you hover the pointer over the question mark icon next to the Select volume to boot from line.

      Immediately after you install the environment or when the environment is disconnected, the list of volumes to boot from is empty. In that case, three operating system logos are displayed: Windows, RHEL, and Linux. You can add a new volume that meets your requirements by clicking the Add volume button.

  3. Click an instance type tile and select the resource size appropriate for your workload.
  4. Optional: Choose the virtual machine details, including the VM’s name, that apply to the volume you are booting from:

    • For a Linux-based volume, follow these steps to configure SSH:

      1. If you have not already added a public SSH key to your project, click the edit icon beside Authorized SSH key in the VirtualMachine details section.
      2. Select one of the following options:

        • Use existing: Select a secret from the secrets list.
        • Add new: Follow these steps:

          1. Browse to the public SSH key file or paste the file in the key field.
          2. Enter the secret name.
          3. Optional: Select Automatically apply this key to any new VirtualMachine you create in this project.
      3. Click Save.
    • For a Windows volume, follow either of these set of steps to configure sysprep options:

      • If you have not already added sysprep options for the Windows volume, follow these steps:

        1. Click the edit icon beside Sysprep in the VirtualMachine details section.
        2. Add the Autoattend.xml answer file.
        3. Add the Unattend.xml answer file.
        4. Click Save.
      • If you want to use existing sysprep options for the Windows volume, follow these steps:

        1. Click Attach existing sysprep.
        2. Enter the name of the existing sysprep Unattend.xml answer file.
        3. Click Save.
  5. Optional: If you are creating a Windows VM, you can mount a Windows driver disk:

    1. Click the Customize VirtualMachine button.
    2. On the VirtualMachine details page, click Storage.
    3. Select the Mount Windows drivers disk checkbox.
  6. Optional: Click View YAML & CLI to view the YAML file. Click CLI to view the CLI commands. You can also download or copy either the YAML file contents or the CLI commands.
  7. Click Create VirtualMachine.

After the VM is created, you can monitor the status on the VirtualMachine details page.

7.1.3. Creating virtual machines from templates

You can create virtual machines (VMs) from Red Hat templates by using the OpenShift Container Platform web console.

7.1.3.1. About VM templates
Boot sources

You can expedite VM creation by using templates that have an available boot source. Templates with a boot source are labeled Available boot source if they do not have a custom label.

Templates without a boot source are labeled Boot source required. See Creating virtual machines from custom images.

Customization
You can customize the disk source and VM parameters before you start the VM.

See storage volume types and storage fields for details about disk source settings.

Note

If you copy a VM template with all its labels and annotations, your version of the template is marked as deprecated when a new version of the Scheduling, Scale, and Performance (SSP) Operator is deployed. You can remove this designation. See Customizing a VM template by using the web console.

Single-node OpenShift
Due to differences in storage behavior, some templates are incompatible with single-node OpenShift. To ensure compatibility, do not set the evictionStrategy field for templates or VMs that use data volumes or storage profiles.
7.1.3.2. Creating a VM from a template

You can create a virtual machine (VM) from a template with an available boot source by using the OpenShift Container Platform web console.

Optional: You can customize template or VM parameters, such as data sources, cloud-init, or SSH keys, before you start the VM.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click Boot source available to filter templates with boot sources.

    The catalog displays the default templates. Click All Items to view all available templates for your filters.

  3. Click a template tile to view its details.
  4. Optional: If you are using a Windows template, you can mount a Windows driver disk by selecting the Mount Windows drivers disk checkbox.
  5. If you do not need to customize the template or VM parameters, click Quick create VirtualMachine to create a VM from the template.

    If you need to customize the template or VM parameters, do the following:

    1. Click Customize VirtualMachine.
    2. Expand Storage or Optional parameters to edit data source settings.
    3. Click Customize VirtualMachine parameters.

      The Customize and create VirtualMachine pane displays the Overview, YAML, Scheduling, Environment, Network interfaces, Disks, Scripts, and Metadata tabs.

    4. Edit the parameters that must be set before the VM boots, such as cloud-init or a static SSH key.
    5. Click Create VirtualMachine.

      The VirtualMachine details page displays the provisioning status.

7.1.3.2.1. Storage volume types
Table 7.2. Storage volume types
TypeDescription

ephemeral

A local copy-on-write (COW) image that uses a network volume as a read-only backing store. The backing volume must be a PersistentVolumeClaim. The ephemeral image is created when the virtual machine starts and stores all writes locally. The ephemeral image is discarded when the virtual machine is stopped, restarted, or deleted. The backing volume (PVC) is not mutated in any way.

persistentVolumeClaim

Attaches an available PV to a virtual machine. Attaching a PV allows for the virtual machine data to persist between sessions.

Importing an existing virtual machine disk into a PVC by using CDI and attaching the PVC to a virtual machine instance is the recommended method for importing existing virtual machines into OpenShift Container Platform. There are some requirements for the disk to be used within a PVC.

dataVolume

Data volumes build on the persistentVolumeClaim disk type by managing the process of preparing the virtual machine disk via an import, clone, or upload operation. VMs that use this volume type are guaranteed not to start until the volume is ready.

Specify type: dataVolume or type: "". If you specify any other value for type, such as persistentVolumeClaim, a warning is displayed, and the virtual machine does not start.

cloudInitNoCloud

Attaches a disk that contains the referenced cloud-init NoCloud data source, providing user data and metadata to the virtual machine. A cloud-init installation is required inside the virtual machine disk.

containerDisk

References an image, such as a virtual machine disk, that is stored in the container image registry. The image is pulled from the registry and attached to the virtual machine as a disk when the virtual machine is launched.

A containerDisk volume is not limited to a single virtual machine and is useful for creating large numbers of virtual machine clones that do not require persistent storage.

Only RAW and QCOW2 formats are supported disk types for the container image registry. QCOW2 is recommended for reduced image size.

Note

A containerDisk volume is ephemeral. It is discarded when the virtual machine is stopped, restarted, or deleted. A containerDisk volume is useful for read-only file systems such as CD-ROMs or for disposable virtual machines.

emptyDisk

Creates an additional sparse QCOW2 disk that is tied to the life-cycle of the virtual machine interface. The data survives guest-initiated reboots in the virtual machine but is discarded when the virtual machine stops or is restarted from the web console. The empty disk is used to store application dependencies and data that otherwise exceeds the limited temporary file system of an ephemeral disk.

The disk capacity size must also be provided.

7.1.3.2.2. Storage fields
FieldDescription

Blank (creates PVC)

Create an empty disk.

Import via URL (creates PVC)

Import content via URL (HTTP or HTTPS endpoint).

Use an existing PVC

Use a PVC that is already available in the cluster.

Clone existing PVC (creates PVC)

Select an existing PVC available in the cluster and clone it.

Import via Registry (creates PVC)

Import content via container registry.

Container (ephemeral)

Upload content from a container located in a registry accessible from the cluster. The container disk should be used only for read-only filesystems such as CD-ROMs or temporary virtual machines.

Name

Name of the disk. The name can contain lowercase letters (a-z), numbers (0-9), hyphens (-), and periods (.), up to a maximum of 253 characters. The first and last characters must be alphanumeric. The name must not contain uppercase letters, spaces, or special characters.

Size

Size of the disk in GiB.

Type

Type of disk. Example: Disk or CD-ROM

Interface

Type of disk device. Supported interfaces are virtIO, SATA, and SCSI.

Storage Class

The storage class that is used to create the disk.

Advanced storage settings

The following advanced storage settings are optional and available for Blank, Import via URL, and Clone existing PVC disks.

If you do not specify these parameters, the system uses the default storage profile values.

ParameterOptionParameter description

Volume Mode

Filesystem

Stores the virtual disk on a file system-based volume.

Block

Stores the virtual disk directly on the block volume. Only use Block if the underlying storage supports it.

Access Mode

ReadWriteOnce (RWO)

Volume can be mounted as read-write by a single node.

ReadWriteMany (RWX)

Volume can be mounted as read-write by many nodes at one time.

Note

This mode is required for live migration.

7.1.3.2.3. Customizing a VM template by using the web console

You can customize an existing virtual machine (VM) template by modifying the VM or template parameters, such as data sources, cloud-init, or SSH keys, before you start the VM. If you customize a template by copying it and including all of its labels and annotations, the customized template is marked as deprecated when a new version of the Scheduling, Scale, and Performance (SSP) Operator is deployed.

You can remove the deprecated designation from the customized template.

Procedure

  1. Navigate to VirtualizationTemplates in the web console.
  2. From the list of VM templates, click the template marked as deprecated.
  3. Click Edit next to the pencil icon beside Labels.
  4. Remove the following two labels:

    • template.kubevirt.io/type: "base"
    • template.kubevirt.io/version: "version"
  5. Click Save.
  6. Click the pencil icon beside the number of existing Annotations.
  7. Remove the following annotation:

    • template.kubevirt.io/deprecated
  8. Click Save.

7.1.4. Creating virtual machines from the command line

You can create virtual machines (VMs) from the command line by editing or creating a VirtualMachine manifest. You can simplify VM configuration by using an instance type in your VM manifest.

Note
7.1.4.1. Creating manifests by using the virtctl tool

You can use the virtctl CLI utility to simplify creating manifests for VMs, VM instance types, and VM preferences. For more information, see VM manifest creation commands.

7.1.4.2. Creating a VM from a VirtualMachine manifest

You can create a virtual machine (VM) from a VirtualMachine manifest.

Procedure

  1. Edit the VirtualMachine manifest for your VM. The following example configures a Red Hat Enterprise Linux (RHEL) VM:

    Note

    This example manifest does not configure VM authentication.

    Example manifest for a RHEL VM

     apiVersion: kubevirt.io/v1
     kind: VirtualMachine
     metadata:
      name: rhel-9-minimal
     spec:
      dataVolumeTemplates:
        - metadata:
            name: rhel-9-minimal-volume
          spec:
            sourceRef:
              kind: DataSource
              name: rhel9 1
              namespace: openshift-virtualization-os-images 2
            storage: {}
      instancetype:
        name: u1.medium 3
      preference:
        name: rhel.9 4
      running: true
      template:
        spec:
          domain:
            devices: {}
          volumes:
            - dataVolume:
                name: rhel-9-minimal-volume
              name: rootdisk

    1
    The rhel9 golden image is used to install RHEL 9 as the guest operating system.
    2
    Golden images are stored in the openshift-virtualization-os-images namespace.
    3
    The u1.medium instance type requests 1 vCPU and 4Gi memory for the VM. These resource values cannot be overridden within the VM.
    4
    The rhel.9 preference specifies additional attributes that support the RHEL 9 guest operating system.
  2. Create a virtual machine by using the manifest file:

    $ oc create -f <vm_manifest_file>.yaml
  3. Optional: Start the virtual machine:

    $ virtctl start <vm_name> -n <namespace>

7.2. Creating VMs from custom images

7.2.1. Creating virtual machines from custom images overview

You can create virtual machines (VMs) from custom operating system images by using one of the following methods:

The Containerized Data Importer (CDI) imports the image into a PVC by using a data volume. You add the PVC to the VM by using the OpenShift Container Platform web console or command line.

Important

You must install the QEMU guest agent on VMs created from operating system images that are not provided by Red Hat.

You must also install VirtIO drivers on Windows VMs.

The QEMU guest agent is included with Red Hat images.

7.2.2. Creating VMs by using container disks

You can create virtual machines (VMs) by using container disks built from operating system images.

You can enable auto updates for your container disks. See Managing automatic boot source updates for details.

Important

If the container disks are large, the I/O traffic might increase and cause worker nodes to be unavailable. You can perform the following tasks to resolve this issue:

You create a VM from a container disk by performing the following steps:

  1. Build an operating system image into a container disk and upload it to your container registry.
  2. If your container registry does not have TLS, configure your environment to disable TLS for your registry.
  3. Create a VM with the container disk as the disk source by using the web console or the command line.
Important

You must install the QEMU guest agent on VMs created from operating system images that are not provided by Red Hat.

7.2.2.1. Building and uploading a container disk

You can build a virtual machine (VM) image into a container disk and upload it to a registry.

The size of a container disk is limited by the maximum layer size of the registry where the container disk is hosted.

Note

For Red Hat Quay, you can change the maximum layer size by editing the YAML configuration file that is created when Red Hat Quay is first deployed.

Prerequisites

  • You must have podman installed.
  • You must have a QCOW2 or RAW image file.

Procedure

  1. Create a Dockerfile to build the VM image into a container image. The VM image must be owned by QEMU, which has a UID of 107, and placed in the /disk/ directory inside the container. Permissions for the /disk/ directory must then be set to 0440.

    The following example uses the Red Hat Universal Base Image (UBI) to handle these configuration changes in the first stage, and uses the minimal scratch image in the second stage to store the result:

    $ cat > Dockerfile << EOF
    FROM registry.access.redhat.com/ubi8/ubi:latest AS builder
    ADD --chown=107:107 <vm_image>.qcow2 /disk/ 1
    RUN chmod 0440 /disk/*
    
    FROM scratch
    COPY --from=builder /disk/* /disk/
    EOF
    1
    Where <vm_image> is the image in either QCOW2 or RAW format. If you use a remote image, replace <vm_image>.qcow2 with the complete URL.
  2. Build and tag the container:

    $ podman build -t <registry>/<container_disk_name>:latest .
  3. Push the container image to the registry:

    $ podman push <registry>/<container_disk_name>:latest
7.2.2.2. Disabling TLS for a container registry

You can disable TLS (transport layer security) for one or more container registries by editing the insecureRegistries field of the HyperConverged custom resource.

Prerequisites

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Add a list of insecure registries to the spec.storageImport.insecureRegistries field.

    Example HyperConverged custom resource

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      storageImport:
        insecureRegistries: 1
          - "private-registry-example-1:5000"
          - "private-registry-example-2:5000"

    1
    Replace the examples in this list with valid registry hostnames.
7.2.2.3. Creating a VM from a container disk by using the web console

You can create a virtual machine (VM) by importing a container disk from a container registry by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click a template tile without an available boot source.
  3. Click Customize VirtualMachine.
  4. On the Customize template parameters page, expand Storage and select Registry (creates PVC) from the Disk source list.
  5. Enter the container image URL. Example: https://mirror.arizona.edu/fedora/linux/releases/38/Cloud/x86_64/images/Fedora-Cloud-Base-38-1.6.x86_64.qcow2
  6. Set the disk size.
  7. Click Next.
  8. Click Create VirtualMachine.
7.2.2.4. Creating a VM from a container disk by using the command line

You can create a virtual machine (VM) from a container disk by using the command line.

When the virtual machine (VM) is created, the data volume with the container disk is imported into persistent storage.

Prerequisites

  • You must have access credentials for the container registry that contains the container disk.

Procedure

  1. Edit the VirtualMachine manifest and save it as a vm-rhel-datavolume.yaml file:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      creationTimestamp: null
      name: vm-rhel-datavolume 1
      labels:
        kubevirt.io/vm: vm-rhel-datavolume
    spec:
      dataVolumeTemplates:
      - metadata:
          creationTimestamp: null
          name: rhel-dv 2
        spec:
          sourceRef:
            kind: DataSource
            name: rhel9
            namespace: openshift-virtualization-os-images
          storage:
            resources:
              requests:
                storage: 10Gi 3
      instancetype:
        name: u1.small 4
      preference:
        inferFromVolume: datavolumedisk1
      runStrategy: Always
      template:
        metadata:
          creationTimestamp: null
          labels:
            kubevirt.io/vm: vm-rhel-datavolume
        spec:
          domain:
            devices: {}
            resources: {}
          terminationGracePeriodSeconds: 180
          volumes:
          - dataVolume:
              name: rhel-dv
            name: datavolumedisk1
    status: {}
    1
    Specify the name of the VM.
    2
    Specify the name of the data volume.
    3
    Specify the size of the storage requested for the data volume.
    4
    Optional: Specify the instance type to use to control resource sizing of the VM.
  2. Create the VM by running the following command:

    $ oc create -f vm-rhel-datavolume.yaml

    The oc create command creates the data volume and the VM. The CDI controller creates an underlying PVC with the correct annotation and the import process begins. When the import is complete, the data volume status changes to Succeeded. You can start the VM.

    Data volume provisioning happens in the background, so there is no need to monitor the process.

Verification

  1. The importer pod downloads the container disk from the specified URL and stores it on the provisioned persistent volume. View the status of the importer pod by running the following command:

    $ oc get pods
  2. Monitor the data volume until its status is Succeeded by running the following command:

    $ oc describe dv rhel-dv 1
    1
    Specify the data volume name that you defined in the VirtualMachine manifest.
  3. Verify that provisioning is complete and that the VM has started by accessing its serial console:

    $ virtctl console vm-rhel-datavolume

7.2.3. Creating VMs by importing images from web pages

You can create virtual machines (VMs) by importing operating system images from web pages.

Important

You must install the QEMU guest agent on VMs created from operating system images that are not provided by Red Hat.

7.2.3.1. Creating a VM from an image on a web page by using the web console

You can create a virtual machine (VM) by importing an image from a web page by using the OpenShift Container Platform web console.

Prerequisites

  • You must have access to the web page that contains the image.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click a template tile without an available boot source.
  3. Click Customize VirtualMachine.
  4. On the Customize template parameters page, expand Storage and select URL (creates PVC) from the Disk source list.
  5. Enter the image URL. Example: https://access.redhat.com/downloads/content/69/ver=/rhel---7/7.9/x86_64/product-software
  6. Enter the container image URL. Example: https://mirror.arizona.edu/fedora/linux/releases/38/Cloud/x86_64/images/Fedora-Cloud-Base-38-1.6.x86_64.qcow2
  7. Set the disk size.
  8. Click Next.
  9. Click Create VirtualMachine.
7.2.3.2. Creating a VM from an image on a web page by using the command line

You can create a virtual machine (VM) from an image on a web page by using the command line.

When the virtual machine (VM) is created, the data volume with the image is imported into persistent storage.

Prerequisites

  • You must have access credentials for the web page that contains the image.

Procedure

  1. Edit the VirtualMachine manifest and save it as a vm-rhel-datavolume.yaml file:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      creationTimestamp: null
      name: vm-rhel-datavolume 1
      labels:
        kubevirt.io/vm: vm-rhel-datavolume
    spec:
      dataVolumeTemplates:
      - metadata:
          creationTimestamp: null
          name: rhel-dv 2
        spec:
          sourceRef:
            kind: DataSource
            name: rhel9
            namespace: openshift-virtualization-os-images
          storage:
            resources:
              requests:
                storage: 10Gi 3
      instancetype:
        name: u1.small 4
      preference:
        inferFromVolume: datavolumedisk1
      runStrategy: Always
      template:
        metadata:
          creationTimestamp: null
          labels:
            kubevirt.io/vm: vm-rhel-datavolume
        spec:
          domain:
            devices: {}
            resources: {}
          terminationGracePeriodSeconds: 180
          volumes:
          - dataVolume:
              name: rhel-dv
            name: datavolumedisk1
    status: {}
    1
    Specify the name of the VM.
    2
    Specify the name of the data volume.
    3
    Specify the size of the storage requested for the data volume.
    4
    Optional: Specify the instance type to use to control resource sizing of the VM.
  2. Create the VM by running the following command:

    $ oc create -f vm-rhel-datavolume.yaml

    The oc create command creates the data volume and the VM. The CDI controller creates an underlying PVC with the correct annotation and the import process begins. When the import is complete, the data volume status changes to Succeeded. You can start the VM.

    Data volume provisioning happens in the background, so there is no need to monitor the process.

Verification

  1. The importer pod downloads the image from the specified URL and stores it on the provisioned persistent volume. View the status of the importer pod by running the following command:

    $ oc get pods
  2. Monitor the data volume until its status is Succeeded by running the following command:

    $ oc describe dv rhel-dv 1
    1
    Specify the data volume name that you defined in the VirtualMachine manifest.
  3. Verify that provisioning is complete and that the VM has started by accessing its serial console:

    $ virtctl console vm-rhel-datavolume

7.2.4. Creating VMs by uploading images

You can create virtual machines (VMs) by uploading operating system images from your local machine.

You can create a Windows VM by uploading a Windows image to a PVC. Then you clone the PVC when you create the VM.

Important

You must install the QEMU guest agent on VMs created from operating system images that are not provided by Red Hat.

You must also install VirtIO drivers on Windows VMs.

7.2.4.1. Creating a VM from an uploaded image by using the web console

You can create a virtual machine (VM) from an uploaded operating system image by using the OpenShift Container Platform web console.

Prerequisites

  • You must have an IMG, ISO, or QCOW2 image file.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click a template tile without an available boot source.
  3. Click Customize VirtualMachine.
  4. On the Customize template parameters page, expand Storage and select Upload (Upload a new file to a PVC) from the Disk source list.
  5. Browse to the image on your local machine and set the disk size.
  6. Click Customize VirtualMachine.
  7. Click Create VirtualMachine.
7.2.4.1.1. Generalizing a VM image

You can generalize a Red Hat Enterprise Linux (RHEL) image to remove all system-specific configuration data before you use the image to create a golden image, a preconfigured snapshot of a virtual machine (VM). You can use a golden image to deploy new VMs.

You can generalize a RHEL VM by using the virtctl, guestfs, and virt-sysprep tools.

Prerequisites

  • You have a RHEL virtual machine (VM) to use as a base VM.
  • You have installed the OpenShift CLI (oc).
  • You have installed the virtctl tool.

Procedure

  1. Stop the RHEL VM if it is running, by entering the following command:

    $ virtctl stop <my_vm_name>
  2. Optional: Clone the virtual machine to avoid losing the data from your original VM. You can then generalize the cloned VM.
  3. Retrieve the dataVolume that stores the root filesystem for the VM by running the following command:

    $ oc get vm <my_vm_name> -o jsonpath="{.spec.template.spec.volumes}{'\n'}"

    Example output

    [{"dataVolume":{"name":"<my_vm_volume>"},"name":"rootdisk"},{"cloudInitNoCloud":{...}]

  4. Retrieve the persistent volume claim (PVC) that matches the listed dataVolume by running the followimg command:

    $ oc get pvc

    Example output

    NAME            STATUS   VOLUME  CAPACITY   ACCESS MODES  STORAGECLASS     AGE
    <my_vm_volume> Bound  …

    Note

    If your cluster configuration does not enable you to clone a VM, to avoid losing the data from your original VM, you can clone the VM PVC to a data volume instead. You can then use the cloned PVC to create a golden image.

    If you are creating a golden image by cloning a PVC, continue with the next steps, using the cloned PVC.

  5. Deploy a new interactive container with libguestfs-tools and attach the PVC to it by running the following command:

    $ virtctl guestfs <my-vm-volume> --uid 107

    This command opens a shell for you to run the next command.

  6. Remove all configurations specific to your system by running the following command:

    $ virt-sysprep -a disk.img
  7. In the OpenShift Container Platform console, click VirtualizationCatalog.
  8. Click Add volume.
  9. In the Add volume window:

    1. From the Source type list, select Use existing Volume.
    2. From the Volume project list, select your project.
    3. From the Volume name list, select the correct PVC.
    4. In the Volume name field, enter a name for the new golden image.
    5. From the Preference list, select the RHEL version you are using.
    6. From the Default Instance Type list, select the instance type with the correct CPU and memory requirements for the version of RHEL you selected previously.
    7. Click Save.

The new volume appears in the Select volume to boot from list. This is your new golden image. You can use this volume to create new VMs.

Additional resources for generalizing VMs

7.2.4.2. Creating a Windows VM

You can create a Windows virtual machine (VM) by uploading a Windows image to a persistent volume claim (PVC) and then cloning the PVC when you create a VM by using the OpenShift Container Platform web console.

Prerequisites

Procedure

  1. Upload the Windows image as a new PVC:

    1. Navigate to StoragePersistentVolumeClaims in the web console.
    2. Click Create PersistentVolumeClaimWith Data upload form.
    3. Browse to the Windows image and select it.
    4. Enter the PVC name, select the storage class and size and then click Upload.

      The Windows image is uploaded to a PVC.

  2. Configure a new VM by cloning the uploaded PVC:

    1. Navigate to VirtualizationCatalog.
    2. Select a Windows template tile and click Customize VirtualMachine.
    3. Select Clone (clone PVC) from the Disk source list.
    4. Select the PVC project, the Windows image PVC, and the disk size.
  3. Apply the answer file to the VM:

    1. Click Customize VirtualMachine parameters.
    2. On the Sysprep section of the Scripts tab, click Edit.
    3. Browse to the autounattend.xml answer file and click Save.
  4. Set the run strategy of the VM:

    1. Clear Start this VirtualMachine after creation so that the VM does not start immediately.
    2. Click Create VirtualMachine.
    3. On the YAML tab, replace running:false with runStrategy: RerunOnFailure and click Save.
  5. Click the options menu kebab and select Start.

    The VM boots from the sysprep disk containing the autounattend.xml answer file.

7.2.4.2.1. Generalizing a Windows VM image

You can generalize a Windows operating system image to remove all system-specific configuration data before you use the image to create a new virtual machine (VM).

Before generalizing the VM, you must ensure the sysprep tool cannot detect an answer file after the unattended Windows installation.

Prerequisites

  • A running Windows VM with the QEMU guest agent installed.

Procedure

  1. In the OpenShift Container Platform console, click VirtualizationVirtualMachines.
  2. Select a Windows VM to open the VirtualMachine details page.
  3. Click ConfigurationDisks.
  4. Click the Options menu kebab beside the sysprep disk and select Detach.
  5. Click Detach.
  6. Rename C:\Windows\Panther\unattend.xml to avoid detection by the sysprep tool.
  7. Start the sysprep program by running the following command:

    %WINDIR%\System32\Sysprep\sysprep.exe /generalize /shutdown /oobe /mode:vm
  8. After the sysprep tool completes, the Windows VM shuts down. The disk image of the VM is now available to use as an installation image for Windows VMs.

You can now specialize the VM.

7.2.4.2.2. Specializing a Windows VM image

Specializing a Windows virtual machine (VM) configures the computer-specific information from a generalized Windows image onto the VM.

Prerequisites

  • You must have a generalized Windows disk image.
  • You must create an unattend.xml answer file. See the Microsoft documentation for details.

Procedure

  1. In the OpenShift Container Platform console, click VirtualizationCatalog.
  2. Select a Windows template and click Customize VirtualMachine.
  3. Select PVC (clone PVC) from the Disk source list.
  4. Select the PVC project and PVC name of the generalized Windows image.
  5. Click Customize VirtualMachine parameters.
  6. Click the Scripts tab.
  7. In the Sysprep section, click Edit, browse to the unattend.xml answer file, and click Save.
  8. Click Create VirtualMachine.

During the initial boot, Windows uses the unattend.xml answer file to specialize the VM. The VM is now ready to use.

7.2.4.3. Creating a VM from an uploaded image by using the command line

You can upload an operating system image by using the virtctl command line tool. You can use an existing data volume or create a new data volume for the image.

Prerequisites

  • You must have an ISO, IMG, or QCOW2 operating system image file.
  • For best performance, compress the image file by using the virt-sparsify tool or the xz or gzip utilities.
  • You must have virtctl installed.
  • The client machine must be configured to trust the OpenShift Container Platform router’s certificate.

Procedure

  1. Upload the image by running the virtctl image-upload command:

    $ virtctl image-upload dv <datavolume_name> \ 1
      --size=<datavolume_size> \ 2
      --image-path=</path/to/image> \ 3
    1
    The name of the data volume.
    2
    The size of the data volume. For example: --size=500Mi, --size=1G
    3
    The file path of the image.
    Note
    • If you do not want to create a new data volume, omit the --size parameter and include the --no-create flag.
    • When uploading a disk image to a PVC, the PVC size must be larger than the size of the uncompressed virtual disk.
    • To allow insecure server connections when using HTTPS, use the --insecure parameter. When you use the --insecure flag, the authenticity of the upload endpoint is not verified.
  2. Optional. To verify that a data volume was created, view all data volumes by running the following command:

    $ oc get dvs

7.2.5. Installing the QEMU guest agent and VirtIO drivers

The QEMU guest agent is a daemon that runs on the virtual machine (VM) and passes information to the host about the VM, users, file systems, and secondary networks.

You must install the QEMU guest agent on VMs created from operating system images that are not provided by Red Hat.

7.2.5.1. Installing the QEMU guest agent
7.2.5.1.1. Installing the QEMU guest agent on a Linux VM

The qemu-guest-agent is widely available and available by default in Red Hat Enterprise Linux (RHEL) virtual machines (VMs). Install the agent and start the service.

Note

To create snapshots of an online (Running state) VM with the highest integrity, install the QEMU guest agent.

The QEMU guest agent takes a consistent snapshot by attempting to quiesce the VM file system as much as possible, depending on the system workload. This ensures that in-flight I/O is written to the disk before the snapshot is taken. If the guest agent is not present, quiescing is not possible and a best-effort snapshot is taken. The conditions under which the snapshot was taken are reflected in the snapshot indications that are displayed in the web console or CLI.

Procedure

  1. Log in to the VM by using a console or SSH.
  2. Install the QEMU guest agent by running the following command:

    $ yum install -y qemu-guest-agent
  3. Ensure the service is persistent and start it:

    $ systemctl enable --now qemu-guest-agent

Verification

  • Run the following command to verify that AgentConnected is listed in the VM spec:

    $ oc get vm <vm_name>
7.2.5.1.2. Installing the QEMU guest agent on a Windows VM

For Windows virtual machines (VMs), the QEMU guest agent is included in the VirtIO drivers. You can install the drivers during a Windows installation or on an existing Windows VM.

Note

To create snapshots of an online (Running state) VM with the highest integrity, install the QEMU guest agent.

The QEMU guest agent takes a consistent snapshot by attempting to quiesce the VM file system as much as possible, depending on the system workload. This ensures that in-flight I/O is written to the disk before the snapshot is taken. If the guest agent is not present, quiescing is not possible and a best-effort snapshot is taken. The conditions under which the snapshot was taken are reflected in the snapshot indications that are displayed in the web console or CLI.

Procedure

  1. In the Windows guest operating system, use the File Explorer to navigate to the guest-agent directory in the virtio-win CD drive.
  2. Run the qemu-ga-x86_64.msi installer.

Verification

  1. Obtain a list of network services by running the following command:

    $ net start
  2. Verify that the output contains the QEMU Guest Agent.
7.2.5.2. Installing VirtIO drivers on Windows VMs

VirtIO drivers are paravirtualized device drivers required for Microsoft Windows virtual machines (VMs) to run in OpenShift Virtualization. The drivers are shipped with the rest of the images and do not require a separate download.

The container-native-virtualization/virtio-win container disk must be attached to the VM as a SATA CD drive to enable driver installation. You can install VirtIO drivers during Windows installation or added to an existing Windows installation.

After the drivers are installed, the container-native-virtualization/virtio-win container disk can be removed from the VM.

Table 7.3. Supported drivers
Driver nameHardware IDDescription

viostor

VEN_1AF4&DEV_1001
VEN_1AF4&DEV_1042

The block driver. Sometimes labeled as an SCSI Controller in the Other devices group.

viorng

VEN_1AF4&DEV_1005
VEN_1AF4&DEV_1044

The entropy source driver. Sometimes labeled as a PCI Device in the Other devices group.

NetKVM

VEN_1AF4&DEV_1000
VEN_1AF4&DEV_1041

The network driver. Sometimes labeled as an Ethernet Controller in the Other devices group. Available only if a VirtIO NIC is configured.

7.2.5.2.1. Attaching VirtIO container disk to Windows VMs during installation

You must attach the VirtIO container disk to the Windows VM to install the necessary Windows drivers. This can be done during creation of the VM.

Procedure

  1. When creating a Windows VM from a template, click Customize VirtualMachine.
  2. Select Mount Windows drivers disk.
  3. Click the Customize VirtualMachine parameters.
  4. Click Create VirtualMachine.

After the VM is created, the virtio-win SATA CD disk will be attached to the VM.

7.2.5.2.2. Attaching VirtIO container disk to an existing Windows VM

You must attach the VirtIO container disk to the Windows VM to install the necessary Windows drivers. This can be done to an existing VM.

Procedure

  1. Navigate to the existing Windows VM, and click ActionsStop.
  2. Go to VM DetailsConfigurationDisks and click Add disk.
  3. Add windows-driver-disk from container source, set the Type to CD-ROM, and then set the Interface to SATA.
  4. Click Save.
  5. Start the VM, and connect to a graphical console.
7.2.5.2.3. Installing VirtIO drivers during Windows installation

You can install the VirtIO drivers while installing Windows on a virtual machine (VM).

Note

This procedure uses a generic approach to the Windows installation and the installation method might differ between versions of Windows. See the documentation for the version of Windows that you are installing.

Prerequisites

  • A storage device containing the virtio drivers must be attached to the VM.

Procedure

  1. In the Windows operating system, use the File Explorer to navigate to the virtio-win CD drive.
  2. Double-click the drive to run the appropriate installer for your VM.

    For a 64-bit vCPU, select the virtio-win-gt-x64 installer. 32-bit vCPUs are no longer supported.

  3. Optional: During the Custom Setup step of the installer, select the device drivers you want to install. The recommended driver set is selected by default.
  4. After the installation is complete, select Finish.
  5. Reboot the VM.

Verification

  1. Open the system disk on the PC. This is typically C:.
  2. Navigate to Program FilesVirtio-Win.

If the Virtio-Win directory is present and contains a sub-directory for each driver, the installation was successful.

7.2.5.2.4. Installing VirtIO drivers from a SATA CD drive on an existing Windows VM

You can install the VirtIO drivers from a SATA CD drive on an existing Windows virtual machine (VM).

Note

This procedure uses a generic approach to adding drivers to Windows. See the installation documentation for your version of Windows for specific installation steps.

Prerequisites

  • A storage device containing the virtio drivers must be attached to the VM as a SATA CD drive.

Procedure

  1. Start the VM and connect to a graphical console.
  2. Log in to a Windows user session.
  3. Open Device Manager and expand Other devices to list any Unknown device.

    1. Open the Device Properties to identify the unknown device.
    2. Right-click the device and select Properties.
    3. Click the Details tab and select Hardware Ids in the Property list.
    4. Compare the Value for the Hardware Ids with the supported VirtIO drivers.
  4. Right-click the device and select Update Driver Software.
  5. Click Browse my computer for driver software and browse to the attached SATA CD drive, where the VirtIO drivers are located. The drivers are arranged hierarchically according to their driver type, operating system, and CPU architecture.
  6. Click Next to install the driver.
  7. Repeat this process for all the necessary VirtIO drivers.
  8. After the driver installs, click Close to close the window.
  9. Reboot the VM to complete the driver installation.
7.2.5.2.5. Installing VirtIO drivers from a container disk added as a SATA CD drive

You can install VirtIO drivers from a container disk that you add to a Windows virtual machine (VM) as a SATA CD drive.

Tip

Downloading the container-native-virtualization/virtio-win container disk from the Red Hat Ecosystem Catalog is not mandatory, because the container disk is downloaded from the Red Hat registry if it not already present in the cluster. However, downloading reduces the installation time.

Prerequisites

  • You must have access to the Red Hat registry or to the downloaded container-native-virtualization/virtio-win container disk in a restricted environment.

Procedure

  1. Add the container-native-virtualization/virtio-win container disk as a CD drive by editing the VirtualMachine manifest:

    # ...
    spec:
      domain:
        devices:
          disks:
            - name: virtiocontainerdisk
              bootOrder: 2 1
              cdrom:
                bus: sata
    volumes:
      - containerDisk:
          image: container-native-virtualization/virtio-win
        name: virtiocontainerdisk
    1
    OpenShift Virtualization boots the VM disks in the order defined in the VirtualMachine manifest. You can either define other VM disks that boot before the container-native-virtualization/virtio-win container disk or use the optional bootOrder parameter to ensure the VM boots from the correct disk. If you configure the boot order for a disk, you must configure the boot order for the other disks.
  2. Apply the changes:

    • If the VM is not running, run the following command:

      $ virtctl start <vm> -n <namespace>
    • If the VM is running, reboot the VM or run the following command:

      $ oc apply -f <vm.yaml>
  3. After the VM has started, install the VirtIO drivers from the SATA CD drive.
7.2.5.3. Updating VirtIO drivers
7.2.5.3.1. Updating VirtIO drivers on a Windows VM

Update the virtio drivers on a Windows virtual machine (VM) by using the Windows Update service.

Prerequisites

  • The cluster must be connected to the internet. Disconnected clusters cannot reach the Windows Update service.

Procedure

  1. In the Windows Guest operating system, click the Windows key and select Settings.
  2. Navigate to Windows UpdateAdvanced OptionsOptional Updates.
  3. Install all updates from Red Hat, Inc..
  4. Reboot the VM.

Verification

  1. On the Windows VM, navigate to the Device Manager.
  2. Select a device.
  3. Select the Driver tab.
  4. Click Driver Details and confirm that the virtio driver details displays the correct version.

7.2.6. Cloning VMs

You can clone virtual machines (VMs) or create new VMs from snapshots.

7.2.6.1. Cloning a VM by using the web console

You can clone an existing VM by using the web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. Click Actions.
  4. Select Clone.
  5. On the Clone VirtualMachine page, enter the name of the new VM.
  6. (Optional) Select the Start cloned VM checkbox to start the cloned VM.
  7. Click Clone.
7.2.6.2. Creating a VM from an existing snapshot by using the web console

You can create a new VM by copying an existing snapshot.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. Click the Snapshots tab.
  4. Click the actions menu kebab for the snapshot you want to copy.
  5. Select Create VirtualMachine.
  6. Enter the name of the virtual machine.
  7. (Optional) Select the Start this VirtualMachine after creation checkbox to start the new virtual machine.
  8. Click Create.
7.2.6.3. Additional resources

7.2.7. Creating VMs by cloning PVCs

You can create virtual machines (VMs) by cloning existing persistent volume claims (PVCs) with custom images.

You must install the QEMU guest agent on VMs created from operating system images that are not provided by Red Hat.

You clone a PVC by creating a data volume that references a source PVC.

7.2.7.1. About cloning

When cloning a data volume, the Containerized Data Importer (CDI) chooses one of the following Container Storage Interface (CSI) clone methods:

  • CSI volume cloning
  • Smart cloning

Both CSI volume cloning and smart cloning methods are efficient, but they have certain requirements for use. If the requirements are not met, the CDI uses host-assisted cloning. Host-assisted cloning is the slowest and least efficient method of cloning, but it has fewer requirements than either of the other two cloning methods.

7.2.7.1.1. CSI volume cloning

Container Storage Interface (CSI) cloning uses CSI driver features to more efficiently clone a source data volume.

CSI volume cloning has the following requirements:

  • The CSI driver that backs the storage class of the persistent volume claim (PVC) must support volume cloning.
  • For provisioners not recognized by the CDI, the corresponding storage profile must have the cloneStrategy set to CSI Volume Cloning.
  • The source and target PVCs must have the same storage class and volume mode.
  • If you create the data volume, you must have permission to create the datavolumes/source resource in the source namespace.
  • The source volume must not be in use.
7.2.7.1.2. Smart cloning

When a Container Storage Interface (CSI) plugin with snapshot capabilities is available, the Containerized Data Importer (CDI) creates a persistent volume claim (PVC) from a snapshot, which then allows efficient cloning of additional PVCs.

Smart cloning has the following requirements:

  • A snapshot class associated with the storage class must exist.
  • The source and target PVCs must have the same storage class and volume mode.
  • If you create the data volume, you must have permission to create the datavolumes/source resource in the source namespace.
  • The source volume must not be in use.
7.2.7.1.3. Host-assisted cloning

When the requirements for neither Container Storage Interface (CSI) volume cloning nor smart cloning have been met, host-assisted cloning is used as a fallback method. Host-assisted cloning is less efficient than either of the two other cloning methods.

Host-assisted cloning uses a source pod and a target pod to copy data from the source volume to the target volume. The target persistent volume claim (PVC) is annotated with the fallback reason that explains why host-assisted cloning has been used, and an event is created.

Example PVC target annotation

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  annotations:
    cdi.kubevirt.io/cloneFallbackReason: The volume modes of source and target are incompatible
    cdi.kubevirt.io/clonePhase: Succeeded
    cdi.kubevirt.io/cloneType: copy

Example event

NAMESPACE   LAST SEEN   TYPE      REASON                    OBJECT                              MESSAGE
test-ns     0s          Warning   IncompatibleVolumeModes   persistentvolumeclaim/test-target   The volume modes of source and target are incompatible

7.2.7.2. Creating a VM from a PVC by using the web console

You can create a virtual machine (VM) by importing an image from a web page by using the OpenShift Container Platform web console. You can create a virtual machine (VM) by cloning a persistent volume claim (PVC) by using the OpenShift Container Platform web console.

Prerequisites

  • You must have access to the web page that contains the image.
  • You must have access to the namespace that contains the source PVC.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click a template tile without an available boot source.
  3. Click Customize VirtualMachine.
  4. On the Customize template parameters page, expand Storage and select PVC (clone PVC) from the Disk source list.
  5. Enter the image URL. Example: https://access.redhat.com/downloads/content/69/ver=/rhel---7/7.9/x86_64/product-software
  6. Enter the container image URL. Example: https://mirror.arizona.edu/fedora/linux/releases/38/Cloud/x86_64/images/Fedora-Cloud-Base-38-1.6.x86_64.qcow2
  7. Select the PVC project and the PVC name.
  8. Set the disk size.
  9. Click Next.
  10. Click Create VirtualMachine.
7.2.7.3. Creating a VM from a PVC by using the command line

You can create a virtual machine (VM) by cloning the persistent volume claim (PVC) of an existing VM by using the command line.

You can clone a PVC by using one of the following options:

  • Cloning a PVC to a new data volume.

    This method creates a data volume whose lifecycle is independent of the original VM. Deleting the original VM does not affect the new data volume or its associated PVC.

  • Cloning a PVC by creating a VirtualMachine manifest with a dataVolumeTemplates stanza.

    This method creates a data volume whose lifecycle is dependent on the original VM. Deleting the original VM deletes the cloned data volume and its associated PVC.

7.2.7.3.1. Cloning a PVC to a data volume

You can clone the persistent volume claim (PVC) of an existing virtual machine (VM) disk to a data volume by using the command line.

You create a data volume that references the original source PVC. The lifecycle of the new data volume is independent of the original VM. Deleting the original VM does not affect the new data volume or its associated PVC.

Cloning between different volume modes is supported for host-assisted cloning, such as cloning from a block persistent volume (PV) to a file system PV, as long as the source and target PVs belong to the kubevirt content type.

Note

Smart-cloning is faster and more efficient than host-assisted cloning because it uses snapshots to clone PVCs. Smart-cloning is supported by storage providers that support snapshots, such as Red Hat OpenShift Data Foundation.

Cloning between different volume modes is not supported for smart-cloning.

Prerequisites

  • The VM with the source PVC must be powered down.
  • If you clone a PVC to a different namespace, you must have permissions to create resources in the target namespace.
  • Additional prerequisites for smart-cloning:

    • Your storage provider must support snapshots.
    • The source and target PVCs must have the same storage provider and volume mode.
    • The value of the driver key of the VolumeSnapshotClass object must match the value of the provisioner key of the StorageClass object as shown in the following example:

      Example VolumeSnapshotClass object

      kind: VolumeSnapshotClass
      apiVersion: snapshot.storage.k8s.io/v1
      driver: openshift-storage.rbd.csi.ceph.com
      # ...

      Example StorageClass object

      kind: StorageClass
      apiVersion: storage.k8s.io/v1
      # ...
      provisioner: openshift-storage.rbd.csi.ceph.com

Procedure

  1. Create a DataVolume manifest as shown in the following example:

    apiVersion: cdi.kubevirt.io/v1beta1
    kind: DataVolume
    metadata:
      name: <datavolume> 1
    spec:
      source:
        pvc:
          namespace: "<source_namespace>" 2
          name: "<my_vm_disk>" 3
      storage: {}
    1
    Specify the name of the new data volume.
    2
    Specify the namespace of the source PVC.
    3
    Specify the name of the source PVC.
  2. Create the data volume by running the following command:

    $ oc create -f <datavolume>.yaml
    Note

    Data volumes prevent a VM from starting before the PVC is prepared. You can create a VM that references the new data volume while the PVC is being cloned.

7.2.7.3.2. Creating a VM from a cloned PVC by using a data volume template

You can create a virtual machine (VM) that clones the persistent volume claim (PVC) of an existing VM by using a data volume template.

This method creates a data volume whose lifecycle is dependent on the original VM. Deleting the original VM deletes the cloned data volume and its associated PVC.

Prerequisites

  • The VM with the source PVC must be powered down.

Procedure

  1. Create a VirtualMachine manifest as shown in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      labels:
        kubevirt.io/vm: vm-dv-clone
      name: vm-dv-clone 1
    spec:
      running: false
      template:
        metadata:
          labels:
            kubevirt.io/vm: vm-dv-clone
        spec:
          domain:
            devices:
              disks:
              - disk:
                  bus: virtio
                name: root-disk
            resources:
              requests:
                memory: 64M
          volumes:
          - dataVolume:
              name: favorite-clone
            name: root-disk
      dataVolumeTemplates:
      - metadata:
          name: favorite-clone
        spec:
          storage:
            accessModes:
            - ReadWriteOnce
            resources:
              requests:
                storage: 2Gi
          source:
            pvc:
              namespace: <source_namespace> 2
              name: "<source_pvc>" 3
    1
    Specify the name of the VM.
    2
    Specify the namespace of the source PVC.
    3
    Specify the name of the source PVC.
  2. Create the virtual machine with the PVC-cloned data volume:

    $ oc create -f <vm-clone-datavolumetemplate>.yaml

7.3. Connecting to virtual machine consoles

You can connect to the following consoles to access running virtual machines (VMs):

7.3.1. Connecting to the VNC console

You can connect to the VNC console of a virtual machine by using the OpenShift Container Platform web console or the virtctl command line tool.

7.3.1.1. Connecting to the VNC console by using the web console

You can connect to the VNC console of a virtual machine (VM) by using the OpenShift Container Platform web console.

Note

If you connect to a Windows VM with a vGPU assigned as a mediated device, you can switch between the default display and the vGPU display.

Procedure

  1. On the VirtualizationVirtualMachines page, click a VM to open the VirtualMachine details page.
  2. Click the Console tab. The VNC console session starts automatically.
  3. Optional: To switch to the vGPU display of a Windows VM, select Ctl + Alt + 2 from the Send key list.

    • Select Ctl + Alt + 1 from the Send key list to restore the default display.
  4. To end the console session, click outside the console pane and then click Disconnect.
7.3.1.2. Connecting to the VNC console by using virtctl

You can use the virtctl command line tool to connect to the VNC console of a running virtual machine.

Note

If you run the virtctl vnc command on a remote machine over an SSH connection, you must forward the X session to your local machine by running the ssh command with the -X or -Y flags.

Prerequisites

  • You must install the virt-viewer package.

Procedure

  1. Run the following command to start the console session:

    $ virtctl vnc <vm_name>
  2. If the connection fails, run the following command to collect troubleshooting information:

    $ virtctl vnc <vm_name> -v 4
7.3.1.3. Generating a temporary token for the VNC console

To access the VNC of a virtual machine (VM), generate a temporary authentication bearer token for the Kubernetes API.

Note

Kubernetes also supports authentication using client certificates, instead of a bearer token, by modifying the curl command.

Prerequisites

  • A running VM with OpenShift Virtualization 4.14 or later and ssp-operator 4.14 or later

Procedure

  1. Enable the feature gate in the HyperConverged (HCO) custom resource (CR):

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv --type json -p '[{"op": "replace", "path": "/spec/featureGates/deployVmConsoleProxy", "value": true}]'
  2. Generate a token by entering the following command:

    $ curl --header "Authorization: Bearer ${TOKEN}" \
         "https://api.<cluster_fqdn>/apis/token.kubevirt.io/v1alpha1/namespaces/<namespace>/virtualmachines/<vm_name>/vnc?duration=<duration>"

    The <duration> parameter can be set in hours and minutes, with a minimum duration of 10 minutes. For example: 5h30m. If this parameter is not set, the token is valid for 10 minutes by default.

    Sample output:

    { "token": "eyJhb..." }
  3. Optional: Use the token provided in the output to create a variable:

    $ export VNC_TOKEN="<token>"

You can now use the token to access the VNC console of a VM.

Verification

  1. Log in to the cluster by entering the following command:

    $ oc login --token ${VNC_TOKEN}
  2. Test access to the VNC console of the VM by using the virtctl command:

    $ virtctl vnc <vm_name> -n <namespace>
Warning

It is currently not possible to revoke a specific token.

To revoke a token, you must delete the service account that was used to create it. However, this also revokes all other tokens that were created by using the service account. Use the following command with caution:

$ virtctl delete serviceaccount --namespace "<namespace>" "<vm_name>-vnc-access"
7.3.1.3.1. Granting token generation permission for the VNC console by using the cluster role

As a cluster administrator, you can install a cluster role and bind it to a user or service account to allow access to the endpoint that generates tokens for the VNC console.

Procedure

  • Choose to bind the cluster role to either a user or service account.

    • Run the following command to bind the cluster role to a user:

      $ kubectl create rolebinding "${ROLE_BINDING_NAME}" --clusterrole="token.kubevirt.io:generate" --user="${USER_NAME}"
    • Run the following command to bind the cluster role to a service account:

      $ kubectl create rolebinding "${ROLE_BINDING_NAME}" --clusterrole="token.kubevirt.io:generate" --serviceaccount="${SERVICE_ACCOUNT_NAME}"

7.3.2. Connecting to the serial console

You can connect to the serial console of a virtual machine by using the OpenShift Container Platform web console or the virtctl command line tool.

Note

Running concurrent VNC connections to a single virtual machine is not currently supported.

7.3.2.1. Connecting to the serial console by using the web console

You can connect to the serial console of a virtual machine (VM) by using the OpenShift Container Platform web console.

Procedure

  1. On the VirtualizationVirtualMachines page, click a VM to open the VirtualMachine details page.
  2. Click the Console tab. The VNC console session starts automatically.
  3. Click Disconnect to end the VNC console session. Otherwise, the VNC console session continues to run in the background.
  4. Select Serial console from the console list.
  5. To end the console session, click outside the console pane and then click Disconnect.
7.3.2.2. Connecting to the serial console by using virtctl

You can use the virtctl command line tool to connect to the serial console of a running virtual machine.

Procedure

  1. Run the following command to start the console session:

    $ virtctl console <vm_name>
  2. Press Ctrl+] to end the console session.

7.3.3. Connecting to the desktop viewer

You can connect to a Windows virtual machine (VM) by using the desktop viewer and the Remote Desktop Protocol (RDP).

7.3.3.1. Connecting to the desktop viewer by using the web console

You can connect to the desktop viewer of a Windows virtual machine (VM) by using the OpenShift Container Platform web console.

Prerequisites

  • You installed the QEMU guest agent on the Windows VM.
  • You have an RDP client installed.

Procedure

  1. On the VirtualizationVirtualMachines page, click a VM to open the VirtualMachine details page.
  2. Click the Console tab. The VNC console session starts automatically.
  3. Click Disconnect to end the VNC console session. Otherwise, the VNC console session continues to run in the background.
  4. Select Desktop viewer from the console list.
  5. Click Create RDP Service to open the RDP Service dialog.
  6. Select Expose RDP Service and click Save to create a node port service.
  7. Click Launch Remote Desktop to download an .rdp file and launch the desktop viewer.

7.4. Specifying an instance type or preference

You can specify an instance type, a preference, or both to define a set of workload sizing and runtime characteristics for reuse across multiple VMs.

7.4.1. Using flags to specify instance types and preferences

Specify instance types and preferences by using flags.

Prerequisites

  • You must have an instance type, preference, or both on the cluster.

Procedure

  1. To specify an instance type when creating a VM, use the --instancetype flag. To specify a preference, use the --preference flag. The following example includes both flags:

    $ virtctl create vm --instancetype <my_instancetype> --preference <my_preference>
  2. Optional: To specify a namespaced instance type or preference, include the kind in the value passed to the --instancetype or --preference flag command. The namespaced instance type or preference must be in the same namespace you are creating the VM in. The following example includes flags for a namespaced instance type and a namespaced preference:

    $ virtctl create vm --instancetype virtualmachineinstancetype/<my_instancetype> --preference virtualmachinepreference/<my_preference>

7.4.2. Inferring an instance type or preference

Inferring instance types, preferences, or both is enabled by default, and the inferFromVolumeFailure policy of the inferFromVolume attribute is set to Ignore. When inferring from the boot volume, errors are ignored, and the VM is created with the instance type and preference left unset.

However, when flags are applied, the inferFromVolumeFailure policy defaults to Reject. When inferring from the boot volume, errors result in the rejection of the creation of that VM.

You can use the --infer-instancetype and --infer-preference flags to infer which instance type, preference, or both to use to define the workload sizing and runtime characteristics of a VM.

Prerequisites

  • You have installed the virtctl tool.

Procedure

  • To explicitly infer instance types from the volume used to boot the virtual machine, use the --infer-instancetype flag. To explicitly infer preferences, use the --infer-preference flag. The following command includes both flags:

    $ virtctl create vm --volume-import type:pvc,src:my-ns/my-pvc --infer-instancetype --infer-preference

7.4.3. Setting the inferFromVolume labels

Use the following labels on your PVC, data source, or data volume to instruct the inference mechanism which instance type, preference, or both to use when trying to boot from a volume.

  • A cluster-wide instance type: instancetype.kubevirt.io/default-instancetype label.
  • A namespaced instance type: instancetype.kubevirt.io/default-instancetype-kind label. Defaults to the VirtualMachineClusterInstancetype label if left empty.
  • A cluster-wide preference: instancetype.kubevirt.io/default-preference label.
  • A namespaced preference: instancetype.kubevirt.io/default-preference-kind label. Defaults to VirtualMachineClusterPreference label, if left empty.

Prerequisites

  • You must have an instance type, preference, or both on the cluster.

Procedure

  • To apply a label to a data source, use oc label. The following command applies a label that points to a cluster-wide instance type:

    $ oc label DataSource foo instancetype.kubevirt.io/default-instancetype=<my_instancetype>

7.5. Configuring SSH access to virtual machines

You can configure SSH access to virtual machines (VMs) by using the following methods:

  • virtctl ssh command

    You create an SSH key pair, add the public key to a VM, and connect to the VM by running the virtctl ssh command with the private key.

    You can add public SSH keys to Red Hat Enterprise Linux (RHEL) 9 VMs at runtime or at first boot to VMs with guest operating systems that can be configured by using a cloud-init data source.

  • virtctl port-forward command

    You add the virtctl port-foward command to your .ssh/config file and connect to the VM by using OpenSSH.

  • Service

    You create a service, associate the service with the VM, and connect to the IP address and port exposed by the service.

  • Secondary network

    You configure a secondary network, attach a virtual machine (VM) to the secondary network interface, and connect to the DHCP-allocated IP address.

7.5.1. Access configuration considerations

Each method for configuring access to a virtual machine (VM) has advantages and limitations, depending on the traffic load and client requirements.

Services provide excellent performance and are recommended for applications that are accessed from outside the cluster.

If the internal cluster network cannot handle the traffic load, you can configure a secondary network.

virtctl ssh and virtctl port-forwarding commands
  • Simple to configure.
  • Recommended for troubleshooting VMs.
  • virtctl port-forwarding recommended for automated configuration of VMs with Ansible.
  • Dynamic public SSH keys can be used to provision VMs with Ansible.
  • Not recommended for high-traffic applications like Rsync or Remote Desktop Protocol because of the burden on the API server.
  • The API server must be able to handle the traffic load.
  • The clients must be able to access the API server.
  • The clients must have access credentials for the cluster.
Cluster IP service
  • The internal cluster network must be able to handle the traffic load.
  • The clients must be able to access an internal cluster IP address.
Node port service
  • The internal cluster network must be able to handle the traffic load.
  • The clients must be able to access at least one node.
Load balancer service
  • A load balancer must be configured.
  • Each node must be able to handle the traffic load of one or more load balancer services.
Secondary network
  • Excellent performance because traffic does not go through the internal cluster network.
  • Allows a flexible approach to network topology.
  • Guest operating system must be configured with appropriate security because the VM is exposed directly to the secondary network. If a VM is compromised, an intruder could gain access to the secondary network.

7.5.2. Using virtctl ssh

You can add a public SSH key to a virtual machine (VM) and connect to the VM by running the virtctl ssh command.

This method is simple to configure. However, it is not recommended for high traffic loads because it places a burden on the API server.

7.5.2.1. About static and dynamic SSH key management

You can add public SSH keys to virtual machines (VMs) statically at first boot or dynamically at runtime.

Note

Only Red Hat Enterprise Linux (RHEL) 9 supports dynamic key injection.

Static SSH key management

You can add a statically managed SSH key to a VM with a guest operating system that supports configuration by using a cloud-init data source. The key is added to the virtual machine (VM) at first boot.

You can add the key by using one of the following methods:

  • Add a key to a single VM when you create it by using the web console or the command line.
  • Add a key to a project by using the web console. Afterwards, the key is automatically added to the VMs that you create in this project.

Use cases

  • As a VM owner, you can provision all your newly created VMs with a single key.
Dynamic SSH key management

You can enable dynamic SSH key management for a VM with Red Hat Enterprise Linux (RHEL) 9 installed. Afterwards, you can update the key during runtime. The key is added by the QEMU guest agent, which is installed with Red Hat boot sources.

You can disable dynamic key management for security reasons. Then, the VM inherits the key management setting of the image from which it was created.

Use cases

  • Granting or revoking access to VMs: As a cluster administrator, you can grant or revoke remote VM access by adding or removing the keys of individual users from a Secret object that is applied to all VMs in a namespace.
  • User access: You can add your access credentials to all VMs that you create and manage.
  • Ansible provisioning:

    • As an operations team member, you can create a single secret that contains all the keys used for Ansible provisioning.
    • As a VM owner, you can create a VM and attach the keys used for Ansible provisioning.
  • Key rotation:

    • As a cluster administrator, you can rotate the Ansible provisioner keys used by VMs in a namespace.
    • As a workload owner, you can rotate the key for the VMs that you manage.
7.5.2.2. Static key management

You can add a statically managed public SSH key when you create a virtual machine (VM) by using the OpenShift Container Platform web console or the command line. The key is added as a cloud-init data source when the VM boots for the first time.

You can also add a public SSH key to a project when you create a VM by using the web console. The key is saved as a secret and is added automatically to all VMs that you create.

Note

If you add a secret to a project and then delete the VM, the secret is retained because it is a namespace resource. You must delete the secret manually.

7.5.2.2.1. Adding a key when creating a VM from a template

You can add a statically managed public SSH key when you create a virtual machine (VM) by using the OpenShift Container Platform web console. The key is added to the VM as a cloud-init data source at first boot. This method does not affect cloud-init user data.

Optional: You can add a key to a project. Afterwards, this key is added automatically to VMs that you create in the project.

Prerequisites

  • You generated an SSH key pair by running the ssh-keygen command.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click a template tile.

    The guest operating system must support configuration from a cloud-init data source.

  3. Click Customize VirtualMachine.
  4. Click Next.
  5. Click the Scripts tab.
  6. If you have not already added a public SSH key to your project, click the edit icon beside Authorized SSH key and select one of the following options:

    • Use existing: Select a secret from the secrets list.
    • Add new:

      1. Browse to the SSH key file or paste the file in the key field.
      2. Enter the secret name.
      3. Optional: Select Automatically apply this key to any new VirtualMachine you create in this project.
  7. Click Save.
  8. Click Create VirtualMachine.

    The VirtualMachine details page displays the progress of the VM creation.

Verification

  • Click the Scripts tab on the Configuration tab.

    The secret name is displayed in the Authorized SSH key section.

7.5.2.2.2. Adding a key when creating a VM from an instance type by using the web console

You can create a virtual machine (VM) from an instance type by using the OpenShift Container Platform web console. You can also use the web console to create a VM by copying an existing snapshot or to clone a VM.

You can create a VM from a list of available bootable volumes. You can add Linux- or Windows-based volumes to the list.

You can add a statically managed SSH key when you create a virtual machine (VM) from an instance type by using the OpenShift Container Platform web console. The key is added to the VM as a cloud-init data source at first boot. This method does not affect cloud-init user data.

Procedure

  1. In the web console, navigate to VirtualizationCatalog.

    The InstanceTypes tab opens by default.

  2. Select either of the following options:

    • Select a suitable bootable volume from the list. If the list is truncated, click the Show all button to display the entire list.

      Note

      The bootable volume table lists only those volumes in the openshift-virtualization-os-images namespace that have the instancetype.kubevirt.io/default-preference label.

      • Optional: Click the star icon to designate a bootable volume as a favorite. Starred bootable volumes appear first in the volume list.
    • Click Add volume to upload a new volume or to use an existing persistent volume claim (PVC), a volume snapshot, or a containerDisk volume. Click Save.

      Logos of operating systems that are not available in the cluster are shown at the bottom of the list. You can add a volume for the required operating system by clicking the Add volume link.

      In addition, there is a link to the Create a Windows boot source quick start. The same link appears in a popover if you hover the pointer over the question mark icon next to the Select volume to boot from line.

      Immediately after you install the environment or when the environment is disconnected, the list of volumes to boot from is empty. In that case, three operating system logos are displayed: Windows, RHEL, and Linux. You can add a new volume that meets your requirements by clicking the Add volume button.

  3. Click an instance type tile and select the resource size appropriate for your workload.
  4. Optional: Choose the virtual machine details, including the VM’s name, that apply to the volume you are booting from:

    • For a Linux-based volume, follow these steps to configure SSH:

      1. If you have not already added a public SSH key to your project, click the edit icon beside Authorized SSH key in the VirtualMachine details section.
      2. Select one of the following options:

        • Use existing: Select a secret from the secrets list.
        • Add new: Follow these steps:

          1. Browse to the public SSH key file or paste the file in the key field.
          2. Enter the secret name.
          3. Optional: Select Automatically apply this key to any new VirtualMachine you create in this project.
      3. Click Save.
    • For a Windows volume, follow either of these set of steps to configure sysprep options:

      • If you have not already added sysprep options for the Windows volume, follow these steps:

        1. Click the edit icon beside Sysprep in the VirtualMachine details section.
        2. Add the Autoattend.xml answer file.
        3. Add the Unattend.xml answer file.
        4. Click Save.
      • If you want to use existing sysprep options for the Windows volume, follow these steps:

        1. Click Attach existing sysprep.
        2. Enter the name of the existing sysprep Unattend.xml answer file.
        3. Click Save.
  5. Optional: If you are creating a Windows VM, you can mount a Windows driver disk:

    1. Click the Customize VirtualMachine button.
    2. On the VirtualMachine details page, click Storage.
    3. Select the Mount Windows drivers disk checkbox.
  6. Optional: Click View YAML & CLI to view the YAML file. Click CLI to view the CLI commands. You can also download or copy either the YAML file contents or the CLI commands.
  7. Click Create VirtualMachine.

After the VM is created, you can monitor the status on the VirtualMachine details page.

7.5.2.2.3. Adding a key when creating a VM by using the command line

You can add a statically managed public SSH key when you create a virtual machine (VM) by using the command line. The key is added to the VM at first boot.

The key is added to the VM as a cloud-init data source. This method separates the access credentials from the application data in the cloud-init user data. This method does not affect cloud-init user data.

Prerequisites

  • You generated an SSH key pair by running the ssh-keygen command.

Procedure

  1. Create a manifest file for a VirtualMachine object and a Secret object:

    Example manifest

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      dataVolumeTemplates:
        - metadata:
            name: example-vm-volume
          spec:
            sourceRef:
              kind: DataSource
              name: rhel9
              namespace: openshift-virtualization-os-images
            storage:
              resources: {}
      instancetype:
        name: u1.medium
      preference:
        name: rhel.9
      running: true
      template:
        spec:
          domain:
            devices: {}
          volumes:
            - dataVolume:
                name: example-vm-volume
              name: rootdisk
            - cloudInitNoCloud: 1
                userData: |-
                  #cloud-config
                  user: cloud-user
              name: cloudinitdisk
          accessCredentials:
            - sshPublicKey:
                propagationMethod:
                  noCloud: {}
                source:
                  secret:
                    secretName: authorized-keys 2
    ---
    apiVersion: v1
    kind: Secret
    metadata:
      name: authorized-keys
    data:
      key: c3NoLXJzYSB... 3

    1
    Specify the cloudInitNoCloud data source.
    2
    Specify the Secret object name.
    3
    Paste the public SSH key.
  2. Create the VirtualMachine and Secret objects by running the following command:

    $ oc create -f <manifest_file>.yaml
  3. Start the VM by running the following command:

    $ virtctl start vm example-vm -n example-namespace

Verification

  • Get the VM configuration:

    $ oc describe vm example-vm -n example-namespace

    Example output

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      template:
        spec:
          accessCredentials:
            - sshPublicKey:
                propagationMethod:
                  noCloud: {}
                source:
                  secret:
                    secretName: authorized-keys
    # ...

7.5.2.3. Dynamic key management

You can enable dynamic key injection for a virtual machine (VM) by using the OpenShift Container Platform web console or the command line. Then, you can update the key at runtime.

Note

Only Red Hat Enterprise Linux (RHEL) 9 supports dynamic key injection.

If you disable dynamic key injection, the VM inherits the key management method of the image from which it was created.

7.5.2.3.1. Enabling dynamic key injection when creating a VM from a template

You can enable dynamic public SSH key injection when you create a virtual machine (VM) from a template by using the OpenShift Container Platform web console. Then, you can update the key at runtime.

Note

Only Red Hat Enterprise Linux (RHEL) 9 supports dynamic key injection.

The key is added to the VM by the QEMU guest agent, which is installed with RHEL 9.

Prerequisites

  • You generated an SSH key pair by running the ssh-keygen command.

Procedure

  1. Navigate to VirtualizationCatalog in the web console.
  2. Click the Red Hat Enterprise Linux 9 VM tile.
  3. Click Customize VirtualMachine.
  4. Click Next.
  5. Click the Scripts tab.
  6. If you have not already added a public SSH key to your project, click the edit icon beside Authorized SSH key and select one of the following options:

    • Use existing: Select a secret from the secrets list.
    • Add new:

      1. Browse to the SSH key file or paste the file in the key field.
      2. Enter the secret name.
      3. Optional: Select Automatically apply this key to any new VirtualMachine you create in this project.
  7. Set Dynamic SSH key injection to on.
  8. Click Save.
  9. Click Create VirtualMachine.

    The VirtualMachine details page displays the progress of the VM creation.

Verification

  • Click the Scripts tab on the Configuration tab.

    The secret name is displayed in the Authorized SSH key section.

7.5.2.3.2. Enabling dynamic key injection when creating a VM from an instance type by using the web console

You can create a virtual machine (VM) from an instance type by using the OpenShift Container Platform web console. You can also use the web console to create a VM by copying an existing snapshot or to clone a VM.

You can create a VM from a list of available bootable volumes. You can add Linux- or Windows-based volumes to the list.

You can enable dynamic SSH key injection when you create a virtual machine (VM) from an instance type by using the OpenShift Container Platform web console. Then, you can add or revoke the key at runtime.

Note

Only Red Hat Enterprise Linux (RHEL) 9 supports dynamic key injection.

The key is added to the VM by the QEMU guest agent, which is installed with RHEL 9.

Procedure

  1. In the web console, navigate to VirtualizationCatalog.

    The InstanceTypes tab opens by default.

  2. Select either of the following options:

    • Select a suitable bootable volume from the list. If the list is truncated, click the Show all button to display the entire list.

      Note

      The bootable volume table lists only those volumes in the openshift-virtualization-os-images namespace that have the instancetype.kubevirt.io/default-preference label.

      • Optional: Click the star icon to designate a bootable volume as a favorite. Starred bootable volumes appear first in the volume list.
    • Click Add volume to upload a new volume or to use an existing persistent volume claim (PVC), a volume snapshot, or a containerDisk volume. Click Save.

      Logos of operating systems that are not available in the cluster are shown at the bottom of the list. You can add a volume for the required operating system by clicking the Add volume link.

      In addition, there is a link to the Create a Windows boot source quick start. The same link appears in a popover if you hover the pointer over the question mark icon next to the Select volume to boot from line.

      Immediately after you install the environment or when the environment is disconnected, the list of volumes to boot from is empty. In that case, three operating system logos are displayed: Windows, RHEL, and Linux. You can add a new volume that meets your requirements by clicking the Add volume button.

  3. Click an instance type tile and select the resource size appropriate for your workload.
  4. Click the Red Hat Enterprise Linux 9 VM tile.
  5. Optional: Choose the virtual machine details, including the VM’s name, that apply to the volume you are booting from:

    • For a Linux-based volume, follow these steps to configure SSH:

      1. If you have not already added a public SSH key to your project, click the edit icon beside Authorized SSH key in the VirtualMachine details section.
      2. Select one of the following options:

        • Use existing: Select a secret from the secrets list.
        • Add new: Follow these steps:

          1. Browse to the public SSH key file or paste the file in the key field.
          2. Enter the secret name.
          3. Optional: Select Automatically apply this key to any new VirtualMachine you create in this project.
      3. Click Save.
    • For a Windows volume, follow either of these set of steps to configure sysprep options:

      • If you have not already added sysprep options for the Windows volume, follow these steps:

        1. Click the edit icon beside Sysprep in the VirtualMachine details section.
        2. Add the Autoattend.xml answer file.
        3. Add the Unattend.xml answer file.
        4. Click Save.
      • If you want to use existing sysprep options for the Windows volume, follow these steps:

        1. Click Attach existing sysprep.
        2. Enter the name of the existing sysprep Unattend.xml answer file.
        3. Click Save.
  6. Set Dynamic SSH key injection in the VirtualMachine details section to on.
  7. Optional: If you are creating a Windows VM, you can mount a Windows driver disk:

    1. Click the Customize VirtualMachine button.
    2. On the VirtualMachine details page, click Storage.
    3. Select the Mount Windows drivers disk checkbox.
  8. Optional: Click View YAML & CLI to view the YAML file. Click CLI to view the CLI commands. You can also download or copy either the YAML file contents or the CLI commands.
  9. Click Create VirtualMachine.

After the VM is created, you can monitor the status on the VirtualMachine details page.

7.5.2.3.3. Enabling dynamic SSH key injection by using the web console

You can enable dynamic key injection for a virtual machine (VM) by using the OpenShift Container Platform web console. Then, you can update the public SSH key at runtime.

The key is added to the VM by the QEMU guest agent, which is installed with Red Hat Enterprise Linux (RHEL) 9.

Prerequisites

  • The guest operating system is RHEL 9.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. On the Configuration tab, click Scripts.
  4. If you have not already added a public SSH key to your project, click the edit icon beside Authorized SSH key and select one of the following options:

    • Use existing: Select a secret from the secrets list.
    • Add new:

      1. Browse to the SSH key file or paste the file in the key field.
      2. Enter the secret name.
      3. Optional: Select Automatically apply this key to any new VirtualMachine you create in this project.
  5. Set Dynamic SSH key injection to on.
  6. Click Save.
7.5.2.3.4. Enabling dynamic key injection by using the command line

You can enable dynamic key injection for a virtual machine (VM) by using the command line. Then, you can update the public SSH key at runtime.

Note

Only Red Hat Enterprise Linux (RHEL) 9 supports dynamic key injection.

The key is added to the VM by the QEMU guest agent, which is installed automatically with RHEL 9.

Prerequisites

  • You generated an SSH key pair by running the ssh-keygen command.

Procedure

  1. Create a manifest file for a VirtualMachine object and a Secret object:

    Example manifest

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      dataVolumeTemplates:
        - metadata:
            name: example-vm-volume
          spec:
            sourceRef:
              kind: DataSource
              name: rhel9
              namespace: openshift-virtualization-os-images
            storage:
              resources: {}
      instancetype:
        name: u1.medium
      preference:
        name: rhel.9
      running: true
      template:
        spec:
          domain:
            devices: {}
          volumes:
            - dataVolume:
                name: example-vm-volume
              name: rootdisk
            - cloudInitNoCloud: 1
                userData: |-
                  #cloud-config
                  runcmd:
                  - [ setsebool, -P, virt_qemu_ga_manage_ssh, on ]
              name: cloudinitdisk
          accessCredentials:
            - sshPublicKey:
                propagationMethod:
                  qemuGuestAgent:
                    users: ["cloud-user"]
                source:
                  secret:
                    secretName: authorized-keys 2
    ---
    apiVersion: v1
    kind: Secret
    metadata:
      name: authorized-keys
    data:
      key: c3NoLXJzYSB... 3

    1
    Specify the cloudInitNoCloud data source.
    2
    Specify the Secret object name.
    3
    Paste the public SSH key.
  2. Create the VirtualMachine and Secret objects by running the following command:

    $ oc create -f <manifest_file>.yaml
  3. Start the VM by running the following command:

    $ virtctl start vm example-vm -n example-namespace

Verification

  • Get the VM configuration:

    $ oc describe vm example-vm -n example-namespace

    Example output

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      template:
        spec:
          accessCredentials:
            - sshPublicKey:
                propagationMethod:
                  qemuGuestAgent:
                    users: ["cloud-user"]
                source:
                  secret:
                    secretName: authorized-keys
    # ...

7.5.2.4. Using the virtctl ssh command

You can access a running virtual machine (VM) by using the virtcl ssh command.

Prerequisites

  • You installed the virtctl command line tool.
  • You added a public SSH key to the VM.
  • You have an SSH client installed.
  • The environment where you installed the virtctl tool has the cluster permissions required to access the VM. For example, you ran oc login or you set the KUBECONFIG environment variable.

Procedure

  • Run the virtctl ssh command:

    $ virtctl -n <namespace> ssh <username>@example-vm -i <ssh_key> 1
    1
    Specify the namespace, user name, and the SSH private key. The default SSH key location is /home/user/.ssh. If you save the key in a different location, you must specify the path.

    Example

    $ virtctl -n my-namespace ssh cloud-user@example-vm -i my-key

Tip

You can copy the virtctl ssh command in the web console by selecting Copy SSH command from the options kebab menu beside a VM on the VirtualMachines page.

7.5.3. Using the virtctl port-forward command

You can use your local OpenSSH client and the virtctl port-forward command to connect to a running virtual machine (VM). You can use this method with Ansible to automate the configuration of VMs.

This method is recommended for low-traffic applications because port-forwarding traffic is sent over the control plane. This method is not recommended for high-traffic applications such as Rsync or Remote Desktop Protocol because it places a heavy burden on the API server.

Prerequisites

  • You have installed the virtctl client.
  • The virtual machine you want to access is running.
  • The environment where you installed the virtctl tool has the cluster permissions required to access the VM. For example, you ran oc login or you set the KUBECONFIG environment variable.

Procedure

  1. Add the following text to the ~/.ssh/config file on your client machine:

    Host vm/*
      ProxyCommand virtctl port-forward --stdio=true %h %p
  2. Connect to the VM by running the following command:

    $ ssh <user>@vm/<vm_name>.<namespace>

7.5.4. Using a service for SSH access

You can create a service for a virtual machine (VM) and connect to the IP address and port exposed by the service.

Services provide excellent performance and are recommended for applications that are accessed from outside the cluster or within the cluster. Ingress traffic is protected by firewalls.

If the cluster network cannot handle the traffic load, consider using a secondary network for VM access.

7.5.4.1. About services

A Kubernetes service exposes network access for clients to an application running on a set of pods. Services offer abstraction, load balancing, and, in the case of the NodePort and LoadBalancer types, exposure to the outside world.

ClusterIP
Exposes the service on an internal IP address and as a DNS name to other applications within the cluster. A single service can map to multiple virtual machines. When a client tries to connect to the service, the client’s request is load balanced among available backends. ClusterIP is the default service type.
NodePort
Exposes the service on the same port of each selected node in the cluster. NodePort makes a port accessible from outside the cluster, as long as the node itself is externally accessible to the client.
LoadBalancer
Creates an external load balancer in the current cloud (if supported) and assigns a fixed, external IP address to the service.
Note

For on-premise clusters, you can configure a load-balancing service by deploying the MetalLB Operator.

7.5.4.2. Creating a service

You can create a service to expose a virtual machine (VM) by using the OpenShift Container Platform web console, virtctl command line tool, or a YAML file.

7.5.4.2.1. Enabling load balancer service creation by using the web console

You can enable the creation of load balancer services for a virtual machine (VM) by using the OpenShift Container Platform web console.

Prerequisites

  • You have configured a load balancer for the cluster.
  • You are logged in as a user with the cluster-admin role.

Procedure

  1. Navigate to VirtualizationOverview.
  2. On the Settings tab, click Cluster.
  3. Expand General settings and SSH configuration.
  4. Set SSH over LoadBalancer service to on.
7.5.4.2.2. Creating a service by using the web console

You can create a node port or load balancer service for a virtual machine (VM) by using the OpenShift Container Platform web console.

Prerequisites

  • You configured the cluster network to support either a load balancer or a node port.
  • To create a load balancer service, you enabled the creation of load balancer services.

Procedure

  1. Navigate to VirtualMachines and select a virtual machine to view the VirtualMachine details page.
  2. On the Details tab, select SSH over LoadBalancer from the SSH service type list.
  3. Optional: Click the copy icon to copy the SSH command to your clipboard.

Verification

  • Check the Services pane on the Details tab to view the new service.
7.5.4.2.3. Creating a service by using virtctl

You can create a service for a virtual machine (VM) by using the virtctl command line tool.

Prerequisites

  • You installed the virtctl command line tool.
  • You configured the cluster network to support the service.
  • The environment where you installed virtctl has the cluster permissions required to access the VM. For example, you ran oc login or you set the KUBECONFIG environment variable.

Procedure

  • Create a service by running the following command:

    $ virtctl expose vm <vm_name> --name <service_name> --type <service_type> --port <port> 1
    1
    Specify the ClusterIP, NodePort, or LoadBalancer service type.

    Example

    $ virtctl expose vm example-vm --name example-service --type NodePort --port 22

Verification

  • Verify the service by running the following command:

    $ oc get service

Next steps

After you create a service with virtctl, you must add special: key to the spec.template.metadata.labels stanza of the VirtualMachine manifest. See Creating a service by using the command line.

7.5.4.2.4. Creating a service by using the command line

You can create a service and associate it with a virtual machine (VM) by using the command line.

Prerequisites

  • You configured the cluster network to support the service.

Procedure

  1. Edit the VirtualMachine manifest to add the label for service creation:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      running: false
      template:
        metadata:
          labels:
            special: key 1
    # ...
    1
    Add special: key to the spec.template.metadata.labels stanza.
    Note

    Labels on a virtual machine are passed through to the pod. The special: key label must match the label in the spec.selector attribute of the Service manifest.

  2. Save the VirtualMachine manifest file to apply your changes.
  3. Create a Service manifest to expose the VM:

    apiVersion: v1
    kind: Service
    metadata:
      name: example-service
      namespace: example-namespace
    spec:
    # ...
      selector:
        special: key 1
      type: NodePort 2
      ports: 3
        protocol: TCP
        port: 80
        targetPort: 9376
        nodePort: 30000
    1
    Specify the label that you added to the spec.template.metadata.labels stanza of the VirtualMachine manifest.
    2
    Specify ClusterIP, NodePort, or LoadBalancer.
    3
    Specifies a collection of network ports and protocols that you want to expose from the virtual machine.
  4. Save the Service manifest file.
  5. Create the service by running the following command:

    $ oc create -f example-service.yaml
  6. Restart the VM to apply the changes.

Verification

  • Query the Service object to verify that it is available:

    $ oc get service -n example-namespace
7.5.4.3. Connecting to a VM exposed by a service by using SSH

You can connect to a virtual machine (VM) that is exposed by a service by using SSH.

Prerequisites

  • You created a service to expose the VM.
  • You have an SSH client installed.
  • You are logged in to the cluster.

Procedure

  • Run the following command to access the VM:

    $ ssh <user_name>@<ip_address> -p <port> 1
    1
    Specify the cluster IP for a cluster IP service, the node IP for a node port service, or the external IP address for a load balancer service.

7.5.5. Using a secondary network for SSH access

You can configure a secondary network, attach a virtual machine (VM) to the secondary network interface, and connect to the DHCP-allocated IP address by using SSH.

Important

Secondary networks provide excellent performance because the traffic is not handled by the cluster network stack. However, the VMs are exposed directly to the secondary network and are not protected by firewalls. If a VM is compromised, an intruder could gain access to the secondary network. You must configure appropriate security within the operating system of the VM if you use this method.

See the Multus and SR-IOV documentation in the OpenShift Virtualization Tuning & Scaling Guide for additional information about networking options.

Prerequisites

7.5.5.1. Configuring a VM network interface by using the web console

You can configure a network interface for a virtual machine (VM) by using the OpenShift Container Platform web console.

Prerequisites

  • You created a network attachment definition for the network.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Click a VM to view the VirtualMachine details page.
  3. On the Configuration tab, click the Network interfaces tab.
  4. Click Add network interface.
  5. Enter the interface name and select the network attachment definition from the Network list.
  6. Click Save.
  7. Restart the VM to apply the changes.
7.5.5.2. Connecting to a VM attached to a secondary network by using SSH

You can connect to a virtual machine (VM) attached to a secondary network by using SSH.

Prerequisites

  • You attached a VM to a secondary network with a DHCP server.
  • You have an SSH client installed.

Procedure

  1. Obtain the IP address of the VM by running the following command:

    $ oc describe vm <vm_name> -n <namespace>

    Example output

    # ...
    Interfaces:
      Interface Name:  eth0
      Ip Address:      10.244.0.37/24
      Ip Addresses:
        10.244.0.37/24
        fe80::858:aff:fef4:25/64
      Mac:             0a:58:0a:f4:00:25
      Name:            default
    # ...

  2. Connect to the VM by running the following command:

    $ ssh <user_name>@<ip_address> -i <ssh_key>

    Example

    $ ssh cloud-user@10.244.0.37 -i ~/.ssh/id_rsa_cloud-user

Note

7.6. Editing virtual machines

You can update a virtual machine (VM) configuration by using the OpenShift Container Platform web console. You can update the YAML file or the VirtualMachine details page.

You can also edit a VM by using the command line.

To edit a VM to configure disk sharing by using virtual disks or LUN, see Configuring shared volumes for virtual machines.

7.6.1. Hot plugging memory on a virtual machine

You can add or remove the amount of memory allocated to a virtual machine (VM) without having to restart the VM by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Select the required VM to open the VirtualMachine details page.
  3. On the Configuration tab, click Edit CPU|Memory.
  4. Enter the desired amount of memory and click Save.

The system applies these changes immediately. If the VM is migratable, a live migration is triggered. If not, or if the changes cannot be live-updated, a RestartRequired condition is added to the VM.

Note

Linux guests require a kernel version of 5.16 or later and Windows guests require the latest viomem drivers.

7.6.2. Hot plugging CPUs on a virtual machine

You can increase or decrease the number of CPU sockets allocated to a virtual machine (VM) without having to restart the VM by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Select the required VM to open the VirtualMachine details page.
  3. On the Configuration tab, click Edit CPU|Memory.
  4. Select the vCPU radio button.
  5. Enter the desired number of vCPU sockets and click Save.

    If the VM is migratable, a live migration is triggered. If not, or if the changes cannot be live-updated, a RestartRequired condition is added to the VM.

7.6.3. Editing a virtual machine by using the command line

You can edit a virtual machine (VM) by using the command line.

Prerequisites

  • You installed the oc CLI.

Procedure

  1. Obtain the virtual machine configuration by running the following command:

    $ oc edit vm <vm_name>
  2. Edit the YAML configuration.
  3. If you edit a running virtual machine, you need to do one of the following:

    • Restart the virtual machine.
    • Run the following command for the new configuration to take effect:

      $ oc apply vm <vm_name> -n <namespace>

7.6.4. Adding a disk to a virtual machine

You can add a virtual disk to a virtual machine (VM) by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. On the Disks tab, click Add disk.
  4. Specify the Source, Name, Size, Type, Interface, and Storage Class.

    1. Optional: You can enable preallocation if you use a blank disk source and require maximum write performance when creating data volumes. To do so, select the Enable preallocation checkbox.
    2. Optional: You can clear Apply optimized StorageProfile settings to change the Volume Mode and Access Mode for the virtual disk. If you do not specify these parameters, the system uses the default values from the kubevirt-storage-class-defaults config map.
  5. Click Add.
Note

If the VM is running, you must restart the VM to apply the change.

7.6.4.1. Storage fields
FieldDescription

Blank (creates PVC)

Create an empty disk.

Import via URL (creates PVC)

Import content via URL (HTTP or HTTPS endpoint).

Use an existing PVC

Use a PVC that is already available in the cluster.

Clone existing PVC (creates PVC)

Select an existing PVC available in the cluster and clone it.

Import via Registry (creates PVC)

Import content via container registry.

Container (ephemeral)

Upload content from a container located in a registry accessible from the cluster. The container disk should be used only for read-only filesystems such as CD-ROMs or temporary virtual machines.

Name

Name of the disk. The name can contain lowercase letters (a-z), numbers (0-9), hyphens (-), and periods (.), up to a maximum of 253 characters. The first and last characters must be alphanumeric. The name must not contain uppercase letters, spaces, or special characters.

Size

Size of the disk in GiB.

Type

Type of disk. Example: Disk or CD-ROM

Interface

Type of disk device. Supported interfaces are virtIO, SATA, and SCSI.

Storage Class

The storage class that is used to create the disk.

Advanced storage settings

The following advanced storage settings are optional and available for Blank, Import via URL, and Clone existing PVC disks.

If you do not specify these parameters, the system uses the default storage profile values.

ParameterOptionParameter description

Volume Mode

Filesystem

Stores the virtual disk on a file system-based volume.

Block

Stores the virtual disk directly on the block volume. Only use Block if the underlying storage supports it.

Access Mode

ReadWriteOnce (RWO)

Volume can be mounted as read-write by a single node.

ReadWriteMany (RWX)

Volume can be mounted as read-write by many nodes at one time.

Note

This mode is required for live migration.

7.6.5. Mounting a Windows driver disk on a virtual machine

You can mount a Windows driver disk on a virtual machine (VM) by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Select the required VM to open the VirtualMachine details page.
  3. On the Configuration tab, click Storage.
  4. Select the Mount Windows drivers disk checkbox.

    The Windows driver disk is displayed in the list of mounted disks.

7.6.6. Adding a secret, config map, or service account to a virtual machine

You add a secret, config map, or service account to a virtual machine by using the OpenShift Container Platform web console.

These resources are added to the virtual machine as disks. You then mount the secret, config map, or service account as you would mount any other disk.

If the virtual machine is running, changes do not take effect until you restart the virtual machine. The newly added resources are marked as pending changes at the top of the page.

Prerequisites

  • The secret, config map, or service account that you want to add must exist in the same namespace as the target virtual machine.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. Click ConfigurationEnvironment.
  4. Click Add Config Map, Secret or Service Account.
  5. Click Select a resource and select a resource from the list. A six character serial number is automatically generated for the selected resource.
  6. Optional: Click Reload to revert the environment to its last saved state.
  7. Click Save.

Verification

  1. On the VirtualMachine details page, click ConfigurationDisks and verify that the resource is displayed in the list of disks.
  2. Restart the virtual machine by clicking ActionsRestart.

You can now mount the secret, config map, or service account as you would mount any other disk.

Additional resources for config maps, secrets, and service accounts

7.7. Editing boot order

You can update the values for a boot order list by using the web console or the CLI.

With Boot Order in the Virtual Machine Overview page, you can:

  • Select a disk or network interface controller (NIC) and add it to the boot order list.
  • Edit the order of the disks or NICs in the boot order list.
  • Remove a disk or NIC from the boot order list, and return it back to the inventory of bootable sources.

7.7.1. Adding items to a boot order list in the web console

Add items to a boot order list by using the web console.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. Click the Details tab.
  4. Click the pencil icon that is located on the right side of Boot Order. If a YAML configuration does not exist, or if this is the first time that you are creating a boot order list, the following message displays: No resource selected. VM will attempt to boot from disks by order of appearance in YAML file.
  5. Click Add Source and select a bootable disk or network interface controller (NIC) for the virtual machine.
  6. Add any additional disks or NICs to the boot order list.
  7. Click Save.
Note

If the virtual machine is running, changes to Boot Order will not take effect until you restart the virtual machine.

You can view pending changes by clicking View Pending Changes on the right side of the Boot Order field. The Pending Changes banner at the top of the page displays a list of all changes that will be applied when the virtual machine restarts.

7.7.2. Editing a boot order list in the web console

Edit the boot order list in the web console.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. Click the Details tab.
  4. Click the pencil icon that is located on the right side of Boot Order.
  5. Choose the appropriate method to move the item in the boot order list:

    • If you do not use a screen reader, hover over the arrow icon next to the item that you want to move, drag the item up or down, and drop it in a location of your choice.
    • If you use a screen reader, press the Up Arrow key or Down Arrow key to move the item in the boot order list. Then, press the Tab key to drop the item in a location of your choice.
  6. Click Save.
Note

If the virtual machine is running, changes to the boot order list will not take effect until you restart the virtual machine.

You can view pending changes by clicking View Pending Changes on the right side of the Boot Order field. The Pending Changes banner at the top of the page displays a list of all changes that will be applied when the virtual machine restarts.

7.7.3. Editing a boot order list in the YAML configuration file

Edit the boot order list in a YAML configuration file by using the CLI.

Procedure

  1. Open the YAML configuration file for the virtual machine by running the following command:

    $ oc edit vm <vm_name> -n <namespace>
  2. Edit the YAML file and modify the values for the boot order associated with a disk or network interface controller (NIC). For example:

    disks:
      - bootOrder: 1 1
        disk:
          bus: virtio
        name: containerdisk
      - disk:
          bus: virtio
        name: cloudinitdisk
      - cdrom:
          bus: virtio
        name: cd-drive-1
    interfaces:
      - boot Order: 2 2
        macAddress: '02:96:c4:00:00'
        masquerade: {}
        name: default
    1
    The boot order value specified for the disk.
    2
    The boot order value specified for the network interface controller.
  3. Save the YAML file.

7.7.4. Removing items from a boot order list in the web console

Remove items from a boot order list by using the web console.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. Click the Details tab.
  4. Click the pencil icon that is located on the right side of Boot Order.
  5. Click the Remove icon delete next to the item. The item is removed from the boot order list and saved in the list of available boot sources. If you remove all items from the boot order list, the following message displays: No resource selected. VM will attempt to boot from disks by order of appearance in YAML file.
Note

If the virtual machine is running, changes to Boot Order will not take effect until you restart the virtual machine.

You can view pending changes by clicking View Pending Changes on the right side of the Boot Order field. The Pending Changes banner at the top of the page displays a list of all changes that will be applied when the virtual machine restarts.

7.8. Deleting virtual machines

You can delete a virtual machine from the web console or by using the oc command line interface.

7.8.1. Deleting a virtual machine using the web console

Deleting a virtual machine permanently removes it from the cluster.

Procedure

  1. In the OpenShift Container Platform console, click VirtualizationVirtualMachines from the side menu.
  2. Click the Options menu kebab beside a virtual machine and select Delete.

    Alternatively, click the virtual machine name to open the VirtualMachine details page and click ActionsDelete.

  3. Optional: Select With grace period or clear Delete disks.
  4. Click Delete to permanently delete the virtual machine.

7.8.2. Deleting a virtual machine by using the CLI

You can delete a virtual machine by using the oc command line interface (CLI). The oc client enables you to perform actions on multiple virtual machines.

Prerequisites

  • Identify the name of the virtual machine that you want to delete.

Procedure

  • Delete the virtual machine by running the following command:

    $ oc delete vm <vm_name>
    Note

    This command only deletes a VM in the current project. Specify the -n <project_name> option if the VM you want to delete is in a different project or namespace.

7.9. Exporting virtual machines

You can export a virtual machine (VM) and its associated disks in order to import a VM into another cluster or to analyze the volume for forensic purposes.

You create a VirtualMachineExport custom resource (CR) by using the command line interface.

Alternatively, you can use the virtctl vmexport command to create a VirtualMachineExport CR and to download exported volumes.

Note

You can migrate virtual machines between OpenShift Virtualization clusters by using the Migration Toolkit for Virtualization.

7.9.1. Creating a VirtualMachineExport custom resource

You can create a VirtualMachineExport custom resource (CR) to export the following objects:

  • Virtual machine (VM): Exports the persistent volume claims (PVCs) of a specified VM.
  • VM snapshot: Exports PVCs contained in a VirtualMachineSnapshot CR.
  • PVC: Exports a PVC. If the PVC is used by another pod, such as the virt-launcher pod, the export remains in a Pending state until the PVC is no longer in use.

The VirtualMachineExport CR creates internal and external links for the exported volumes. Internal links are valid within the cluster. External links can be accessed by using an Ingress or Route.

The export server supports the following file formats:

  • raw: Raw disk image file.
  • gzip: Compressed disk image file.
  • dir: PVC directory and files.
  • tar.gz: Compressed PVC file.

Prerequisites

  • The VM must be shut down for a VM export.

Procedure

  1. Create a VirtualMachineExport manifest to export a volume from a VirtualMachine, VirtualMachineSnapshot, or PersistentVolumeClaim CR according to the following example and save it as example-export.yaml:

    VirtualMachineExport example

    apiVersion: export.kubevirt.io/v1beta1
    kind: VirtualMachineExport
    metadata:
      name: example-export
    spec:
      source:
        apiGroup: "kubevirt.io" 1
        kind: VirtualMachine 2
        name: example-vm
      ttlDuration: 1h 3

    1
    Specify the appropriate API group:
    • "kubevirt.io" for VirtualMachine.
    • "snapshot.kubevirt.io" for VirtualMachineSnapshot.
    • "" for PersistentVolumeClaim.
    2
    Specify VirtualMachine, VirtualMachineSnapshot, or PersistentVolumeClaim.
    3
    Optional. The default duration is 2 hours.
  2. Create the VirtualMachineExport CR:

    $ oc create -f example-export.yaml
  3. Get the VirtualMachineExport CR:

    $ oc get vmexport example-export -o yaml

    The internal and external links for the exported volumes are displayed in the status stanza:

    Output example

    apiVersion: export.kubevirt.io/v1beta1
    kind: VirtualMachineExport
    metadata:
      name: example-export
      namespace: example
    spec:
      source:
        apiGroup: ""
        kind: PersistentVolumeClaim
        name: example-pvc
      tokenSecretRef: example-token
    status:
      conditions:
      - lastProbeTime: null
        lastTransitionTime: "2022-06-21T14:10:09Z"
        reason: podReady
        status: "True"
        type: Ready
      - lastProbeTime: null
        lastTransitionTime: "2022-06-21T14:09:02Z"
        reason: pvcBound
        status: "True"
        type: PVCReady
      links:
        external: 1
          cert: |-
            -----BEGIN CERTIFICATE-----
            ...
            -----END CERTIFICATE-----
          volumes:
          - formats:
            - format: raw
              url: https://vmexport-proxy.test.net/api/export.kubevirt.io/v1beta1/namespaces/example/virtualmachineexports/example-export/volumes/example-disk/disk.img
            - format: gzip
              url: https://vmexport-proxy.test.net/api/export.kubevirt.io/v1beta1/namespaces/example/virtualmachineexports/example-export/volumes/example-disk/disk.img.gz
            name: example-disk
        internal:  2
          cert: |-
            -----BEGIN CERTIFICATE-----
            ...
            -----END CERTIFICATE-----
          volumes:
          - formats:
            - format: raw
              url: https://virt-export-example-export.example.svc/volumes/example-disk/disk.img
            - format: gzip
              url: https://virt-export-example-export.example.svc/volumes/example-disk/disk.img.gz
            name: example-disk
      phase: Ready
      serviceName: virt-export-example-export

    1
    External links are accessible from outside the cluster by using an Ingress or Route.
    2
    Internal links are only valid inside the cluster.

7.9.2. Accessing exported virtual machine manifests

After you export a virtual machine (VM) or snapshot, you can get the VirtualMachine manifest and related information from the export server.

Prerequisites

  • You exported a virtual machine or VM snapshot by creating a VirtualMachineExport custom resource (CR).

    Note

    VirtualMachineExport objects that have the spec.source.kind: PersistentVolumeClaim parameter do not generate virtual machine manifests.

Procedure

  1. To access the manifests, you must first copy the certificates from the source cluster to the target cluster.

    1. Log in to the source cluster.
    2. Save the certificates to the cacert.crt file by running the following command:

      $ oc get vmexport <export_name> -o jsonpath={.status.links.external.cert} > cacert.crt 1
      1
      Replace <export_name> with the metadata.name value from the VirtualMachineExport object.
    3. Copy the cacert.crt file to the target cluster.
  2. Decode the token in the source cluster and save it to the token_decode file by running the following command:

    $ oc get secret export-token-<export_name> -o jsonpath={.data.token} | base64 --decode > token_decode 1
    1
    Replace <export_name> with the metadata.name value from the VirtualMachineExport object.
  3. Copy the token_decode file to the target cluster.
  4. Get the VirtualMachineExport custom resource by running the following command:

    $ oc get vmexport <export_name> -o yaml
  5. Review the status.links stanza, which is divided into external and internal sections. Note the manifests.url fields within each section:

    Example output

    apiVersion: export.kubevirt.io/v1beta1
    kind: VirtualMachineExport
    metadata:
      name: example-export
    spec:
      source:
        apiGroup: "kubevirt.io"
        kind: VirtualMachine
        name: example-vm
      tokenSecretRef: example-token
    status:
    #...
      links:
        external:
    #...
          manifests:
          - type: all
            url: https://vmexport-proxy.test.net/api/export.kubevirt.io/v1beta1/namespaces/example/virtualmachineexports/example-export/external/manifests/all 1
          - type: auth-header-secret
            url: https://vmexport-proxy.test.net/api/export.kubevirt.io/v1beta1/namespaces/example/virtualmachineexports/example-export/external/manifests/secret 2
        internal:
    #...
          manifests:
          - type: all
            url: https://virt-export-export-pvc.default.svc/internal/manifests/all 3
          - type: auth-header-secret
            url: https://virt-export-export-pvc.default.svc/internal/manifests/secret
      phase: Ready
      serviceName: virt-export-example-export

    1
    Contains the VirtualMachine manifest, DataVolume manifest, if present, and a ConfigMap manifest that contains the public certificate for the external URL’s ingress or route.
    2
    Contains a secret containing a header that is compatible with Containerized Data Importer (CDI). The header contains a text version of the export token.
    3
    Contains the VirtualMachine manifest, DataVolume manifest, if present, and a ConfigMap manifest that contains the certificate for the internal URL’s export server.
  6. Log in to the target cluster.
  7. Get the Secret manifest by running the following command:

    $ curl --cacert cacert.crt <secret_manifest_url> -H \ 1
    "x-kubevirt-export-token:token_decode" -H \ 2
    "Accept:application/yaml"
    1
    Replace <secret_manifest_url> with an auth-header-secret URL from the VirtualMachineExport YAML output.
    2
    Reference the token_decode file that you created earlier.

    For example:

    $ curl --cacert cacert.crt https://vmexport-proxy.test.net/api/export.kubevirt.io/v1beta1/namespaces/example/virtualmachineexports/example-export/external/manifests/secret -H "x-kubevirt-export-token:token_decode" -H "Accept:application/yaml"
  8. Get the manifests of type: all, such as the ConfigMap and VirtualMachine manifests, by running the following command:

    $ curl --cacert cacert.crt <all_manifest_url> -H \ 1
    "x-kubevirt-export-token:token_decode" -H \ 2
    "Accept:application/yaml"
    1
    Replace <all_manifest_url> with a URL from the VirtualMachineExport YAML output.
    2
    Reference the token_decode file that you created earlier.

    For example:

    $ curl --cacert cacert.crt https://vmexport-proxy.test.net/api/export.kubevirt.io/v1beta1/namespaces/example/virtualmachineexports/example-export/external/manifests/all -H "x-kubevirt-export-token:token_decode" -H "Accept:application/yaml"

Next steps

  • You can now create the ConfigMap and VirtualMachine objects on the target cluster by using the exported manifests.

7.10. Managing virtual machine instances

If you have standalone virtual machine instances (VMIs) that were created independently outside of the OpenShift Virtualization environment, you can manage them by using the web console or by using oc or virtctl commands from the command-line interface (CLI).

The virtctl command provides more virtualization options than the oc command. For example, you can use virtctl to pause a VM or expose a port.

7.10.1. About virtual machine instances

A virtual machine instance (VMI) is a representation of a running virtual machine (VM). When a VMI is owned by a VM or by another object, you manage it through its owner in the web console or by using the oc command-line interface (CLI).

A standalone VMI is created and started independently with a script, through automation, or by using other methods in the CLI. In your environment, you might have standalone VMIs that were developed and started outside of the OpenShift Virtualization environment. You can continue to manage those standalone VMIs by using the CLI. You can also use the web console for specific tasks associated with standalone VMIs:

  • List standalone VMIs and their details.
  • Edit labels and annotations for a standalone VMI.
  • Delete a standalone VMI.

When you delete a VM, the associated VMI is automatically deleted. You delete a standalone VMI directly because it is not owned by VMs or other objects.

Note

Before you uninstall OpenShift Virtualization, list and view the standalone VMIs by using the CLI or the web console. Then, delete any outstanding VMIs.

When you edit a VM, some settings might be applied to the VMIs dynamically and without the need for a restart. Any change made to a VM object that cannot be applied to the VMIs dynamically will trigger the RestartRequired VM condition. Changes are effective on the next reboot, and the condition is removed.

7.10.2. Listing all virtual machine instances using the CLI

You can list all virtual machine instances (VMIs) in your cluster, including standalone VMIs and those owned by virtual machines, by using the oc command-line interface (CLI).

Procedure

  • List all VMIs by running the following command:

    $ oc get vmis -A

7.10.3. Listing standalone virtual machine instances using the web console

Using the web console, you can list and view standalone virtual machine instances (VMIs) in your cluster that are not owned by virtual machines (VMs).

Note

VMIs that are owned by VMs or other objects are not displayed in the web console. The web console displays only standalone VMIs. If you want to list all VMIs in your cluster, you must use the CLI.

Procedure

  • Click VirtualizationVirtualMachines from the side menu.

    You can identify a standalone VMI by a dark colored badge next to its name.

7.10.4. Editing a standalone virtual machine instance using the web console

You can edit the annotations and labels of a standalone virtual machine instance (VMI) using the web console. Other fields are not editable.

Procedure

  1. In the OpenShift Container Platform console, click VirtualizationVirtualMachines from the side menu.
  2. Select a standalone VMI to open the VirtualMachineInstance details page.
  3. On the Details tab, click the pencil icon beside Annotations or Labels.
  4. Make the relevant changes and click Save.

7.10.5. Deleting a standalone virtual machine instance using the CLI

You can delete a standalone virtual machine instance (VMI) by using the oc command-line interface (CLI).

Prerequisites

  • Identify the name of the VMI that you want to delete.

Procedure

  • Delete the VMI by running the following command:

    $ oc delete vmi <vmi_name>

7.10.6. Deleting a standalone virtual machine instance using the web console

Delete a standalone virtual machine instance (VMI) from the web console.

Procedure

  1. In the OpenShift Container Platform web console, click VirtualizationVirtualMachines from the side menu.
  2. Click ActionsDelete VirtualMachineInstance.
  3. In the confirmation pop-up window, click Delete to permanently delete the standalone VMI.

7.11. Controlling virtual machine states

You can stop, start, restart, and unpause virtual machines from the web console.

You can use virtctl to manage virtual machine states and perform other actions from the CLI. For example, you can use virtctl to force stop a VM or expose a port.

7.11.1. Starting a virtual machine

You can start a virtual machine from the web console.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Find the row that contains the virtual machine that you want to start.
  3. Navigate to the appropriate menu for your use case:

    • To stay on this page, where you can perform actions on multiple virtual machines:

      1. Click the Options menu kebab located at the far right end of the row and click Start VirtualMachine.
    • To view comprehensive information about the selected virtual machine before you start it:

      1. Access the VirtualMachine details page by clicking the name of the virtual machine.
      2. Click ActionsStart.
Note

When you start virtual machine that is provisioned from a URL source for the first time, the virtual machine has a status of Importing while OpenShift Virtualization imports the container from the URL endpoint. Depending on the size of the image, this process might take several minutes.

7.11.2. Stopping a virtual machine

You can stop a virtual machine from the web console.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Find the row that contains the virtual machine that you want to stop.
  3. Navigate to the appropriate menu for your use case:

    • To stay on this page, where you can perform actions on multiple virtual machines:

      1. Click the Options menu kebab located at the far right end of the row and click Stop VirtualMachine.
    • To view comprehensive information about the selected virtual machine before you stop it:

      1. Access the VirtualMachine details page by clicking the name of the virtual machine.
      2. Click ActionsStop.

7.11.3. Restarting a virtual machine

You can restart a running virtual machine from the web console.

Important

To avoid errors, do not restart a virtual machine while it has a status of Importing.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Find the row that contains the virtual machine that you want to restart.
  3. Navigate to the appropriate menu for your use case:

    • To stay on this page, where you can perform actions on multiple virtual machines:

      1. Click the Options menu kebab located at the far right end of the row and click Restart.
    • To view comprehensive information about the selected virtual machine before you restart it:

      1. Access the VirtualMachine details page by clicking the name of the virtual machine.
      2. Click ActionsRestart.

7.11.4. Pausing a virtual machine

You can pause a virtual machine from the web console.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Find the row that contains the virtual machine that you want to pause.
  3. Navigate to the appropriate menu for your use case:

    • To stay on this page, where you can perform actions on multiple virtual machines:

      1. Click the Options menu kebab located at the far right end of the row and click Pause VirtualMachine.
    • To view comprehensive information about the selected virtual machine before you pause it:

      1. Access the VirtualMachine details page by clicking the name of the virtual machine.
      2. Click ActionsPause.

7.11.5. Unpausing a virtual machine

You can unpause a paused virtual machine from the web console.

Prerequisites

  • At least one of your virtual machines must have a status of Paused.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Find the row that contains the virtual machine that you want to unpause.
  3. Navigate to the appropriate menu for your use case:

    • To stay on this page, where you can perform actions on multiple virtual machines:

      1. Click the Options menu kebab located at the far right end of the row and click Unpause VirtualMachine.
    • To view comprehensive information about the selected virtual machine before you unpause it:

      1. Access the VirtualMachine details page by clicking the name of the virtual machine.
      2. Click ActionsUnpause.

7.12. Using virtual Trusted Platform Module devices

Add a virtual Trusted Platform Module (vTPM) device to a new or existing virtual machine by editing the VirtualMachine (VM) or VirtualMachineInstance (VMI) manifest.

7.12.1. About vTPM devices

A virtual Trusted Platform Module (vTPM) device functions like a physical Trusted Platform Module (TPM) hardware chip.

You can use a vTPM device with any operating system, but Windows 11 requires the presence of a TPM chip to install or boot. A vTPM device allows VMs created from a Windows 11 image to function without a physical TPM chip.

If you do not enable vTPM, then the VM does not recognize a TPM device, even if the node has one.

A vTPM device also protects virtual machines by storing secrets without physical hardware. OpenShift Virtualization supports persisting vTPM device state by using Persistent Volume Claims (PVCs) for VMs. You must specify the storage class to be used by the PVC by setting the vmStateStorageClass attribute in the HyperConverged custom resource (CR):

kind: HyperConverged
metadata:
  name: kubevirt-hyperconverged
spec:
  vmStateStorageClass: <storage_class_name>

# ...
Note

The storage class must be of type Filesystem and support the ReadWriteMany (RWX) access mode.

7.12.2. Adding a vTPM device to a virtual machine

Adding a virtual Trusted Platform Module (vTPM) device to a virtual machine (VM) allows you to run a VM created from a Windows 11 image without a physical TPM device. A vTPM device also stores secrets for that VM.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • You have configured a Persistent Volume Claim (PVC) to use a storage class of type Filesystem that supports the ReadWriteMany (RWX) access mode. This is necessary for the vTPM device data to persist across VM reboots.

Procedure

  1. Run the following command to update the VM configuration:

    $ oc edit vm <vm_name> -n <namespace>
  2. Edit the VM specification to add the vTPM device. For example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
        name: example-vm
    spec:
      template:
        spec:
          domain:
            devices:
              tpm:  1
                persistent: true 2
    # ...
    1
    Adds the vTPM device to the VM.
    2
    Specifies that the vTPM device state persists after the VM is shut down. The default value is false.
  3. To apply your changes, save and exit the editor.
  4. Optional: If you edited a running virtual machine, you must restart it for the changes to take effect.

7.13. Managing virtual machines with OpenShift Pipelines

Red Hat OpenShift Pipelines is a Kubernetes-native CI/CD framework that allows developers to design and run each step of the CI/CD pipeline in its own container.

By using OpenShift Pipelines tasks and the example pipeline, you can do the following:

  • Create and manage virtual machines (VMs), persistent volume claims (PVCs), data volumes, and data sources.
  • Run commands in VMs.
  • Manipulate disk images with libguestfs tools.

The tasks are located in the task catalog (ArtifactHub).

The example Windows pipeline is located in the pipeline catalog (ArtifactHub).

7.13.1. Prerequisites

  • You have access to an OpenShift Container Platform cluster with cluster-admin permissions.
  • You have installed the OpenShift CLI (oc).
  • You have installed OpenShift Pipelines.

7.13.2. Supported virtual machine tasks

The following table shows the supported tasks.

Table 7.4. Supported virtual machine tasks
TaskDescription

create-vm-from-manifest

Create a virtual machine from a provided manifest or with virtctl.

create-vm-from-template

Create a virtual machine from a template.

copy-template

Copy a virtual machine template.

modify-vm-template

Modify a virtual machine template.

modify-data-object

Create or delete data volumes or data sources.

cleanup-vm

Run a script or a command in a virtual machine and stop or delete the virtual machine afterward.

disk-virt-customize

Use the virt-customize tool to run a customization script on a target PVC.

disk-virt-sysprep

Use the virt-sysprep tool to run a sysprep script on a target PVC.

wait-for-vmi-status

Wait for a specific status of a virtual machine instance and fail or succeed based on the status.

Note

Virtual machine creation in pipelines now utilizes ClusterInstanceType and ClusterPreference instead of template-based tasks, which have been deprecated. The create-vm-from-template, copy-template, and modify-vm-template commands remain available but are not used in default pipeline tasks.

7.13.3. Windows EFI installer pipeline

You can run the Windows EFI installer pipeline by using the web console or CLI.

The Windows EFI installer pipeline installs Windows 10, Windows 11, or Windows Server 2022 into a new data volume from a Windows installation image (ISO file). A custom answer file is used to run the installation process.

Note

The Windows EFI installer pipeline uses a config map file with sysprep predefined by OpenShift Container Platform and suitable for Microsoft ISO files. For ISO files pertaining to different Windows editions, it may be necessary to create a new config map file with a system-specific sysprep definition.

7.13.3.1. Running the example pipelines using the web console

You can run the example pipelines from the Pipelines menu in the web console.

Procedure

  1. Click PipelinesPipelines in the side menu.
  2. Select a pipeline to open the Pipeline details page.
  3. From the Actions list, select Start. The Start Pipeline dialog is displayed.
  4. Keep the default values for the parameters and then click Start to run the pipeline. The Details tab tracks the progress of each task and displays the pipeline status.
7.13.3.2. Running the example pipelines using the CLI

Use a PipelineRun resource to run the example pipelines. A PipelineRun object is the running instance of a pipeline. It instantiates a pipeline for execution with specific inputs, outputs, and execution parameters on a cluster. It also creates a TaskRun object for each task in the pipeline.

Procedure

  1. To run the Microsoft Windows 11 installer pipeline, create the following PipelineRun manifest:

    apiVersion: tekton.dev/v1
    kind: PipelineRun
    metadata:
      generateName: windows11-installer-run-
      labels:
        pipelinerun: windows11-installer-run
    spec:
        params:
        -   name: winImageDownloadURL
            value: <windows_image_download_url> 1
        -   name: acceptEula
            value: false 2
        pipelineRef:
            params:
            -   name: catalog
                value: redhat-pipelines
            -   name: type
                value: artifact
            -   name: kind
                value: pipeline
            -   name: name
                value: windows-efi-installer
            -   name: version
                value: 4.17
            resolver: hub
        taskRunSpecs:
        -   pipelineTaskName: modify-windows-iso-file
            PodTemplate:
                securityContext:
                    fsGroup: 107
                    runAsUser: 107
    1
    Specify the URL for the Windows 11 64-bit ISO file. The product’s language must be English (United States).
    2
    Example PipelineRun objects have a special parameter, acceptEula. By setting this parameter, you are agreeing to the applicable Microsoft user license agreements for each deployment or installation of the Microsoft products. If you set it to false, the pipeline exits at the first task.
  2. Apply the PipelineRun manifest:

    $ oc apply -f windows11-customize-run.yaml

7.13.4. Additional resources

7.14. Advanced virtual machine management

7.14.1. Working with resource quotas for virtual machines

Create and manage resource quotas for virtual machines.

7.14.1.1. Setting resource quota limits for virtual machines

Resource quotas that only use requests automatically work with virtual machines (VMs). If your resource quota uses limits, you must manually set resource limits on VMs. Resource limits must be at least 100 MiB larger than resource requests.

Procedure

  1. Set limits for a VM by editing the VirtualMachine manifest. For example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: with-limits
    spec:
      running: false
      template:
        spec:
          domain:
    # ...
            resources:
              requests:
                memory: 128Mi
              limits:
                memory: 256Mi  1
    1
    This configuration is supported because the limits.memory value is at least 100Mi larger than the requests.memory value.
  2. Save the VirtualMachine manifest.
7.14.1.2. Additional resources

7.14.2. Configuring the Application-Aware Quota (AAQ) Operator

You can use the Application-Aware Quota (AAQ) Operator to customize and manage resource quotas for individual components in an OpenShift Container Platform cluster.

7.14.2.1. About the AAQ Operator

The Application-Aware Quota (AAQ) Operator provides more flexible and extensible quota management compared to the native ResourceQuota object in the OpenShift Container Platform platform.

In a multi-tenant cluster environment, where multiple workloads operate on shared infrastructure and resources, using the Kubernetes native ResourceQuota object to limit aggregate CPU and memory consumption presents infrastructure overhead and live migration challenges for OpenShift Virtualization workloads.

OpenShift Virtualization requires significant compute resource allocation to handle virtual machine (VM) live migrations and manage VM infrastructure overhead. When upgrading OpenShift Virtualization, you must migrate VMs to upgrade the virt-launcher pod. However, migrating a VM in the presence of a resource quota can cause the migration, and subsequently the upgrade, to fail.

With AAQ, you can allocate resources for VMs without interfering with cluster-level activities such as upgrades and node maintenance. The AAQ Operator also supports non-compute resources which eliminates the need to manage both the native resource quota and AAQ API objects separately.

7.14.2.1.1. AAQ Operator controller and custom resources

The AAQ Operator introduces two new API objects defined as custom resource definitions (CRDs) for managing alternative quota implementations across multiple namespaces:

  • ApplicationAwareResourceQuota: Sets aggregate quota restrictions enforced per namespace. The ApplicationAwareResourceQuota API is compatible with the native ResourceQuota object and shares the same specification and status definitions.

    Example manifest

    apiVersion: aaq.kubevirt.io/v1alpha1
    kind: ApplicationAwareResourceQuota
    metadata:
      name: example-resource-quota
    spec:
      hard:
        requests.memory: 1Gi
        limits.memory: 1Gi
        requests.cpu/vmi: "1" 1
        requests.memory/vmi: 1Gi 2
    # ...

    1
    The maximum amount of CPU that is allowed for VM workloads in the default namespace.
    2
    The maximum amount of RAM that is allowed for VM workloads in the default namespace.
  • ApplicationAwareClusterResourceQuota: Mirrors the ApplicationAwareResourceQuota object at a cluster scope. It is compatible with the native ClusterResourceQuota API object and shares the same specification and status definitions. When creating an AAQ cluster quota, you can select multiple namespaces based on annotation selection, label selection, or both by editing the spec.selector.labels or spec.selector.annotations fields.

    Example manifest

    apiVersion: aaq.kubevirt.io/v1alpha1
    kind: ApplicationAwareClusterResourceQuota 1
    metadata:
      name: example-resource-quota
    spec:
      quota:
        hard:
        requests.memory: 1Gi
        limits.memory: 1Gi
        requests.cpu/vmi: "1"
        requests.memory/vmi: 1Gi
      selector:
        annotations: null
        labels:
          matchLabels:
            kubernetes.io/metadata.name: default
    # ...

    1
    You can only create an ApplicationAwareClusterResourceQuota object if the spec.allowApplicationAwareClusterResourceQuota field in the HyperConverged custom resource (CR) is set to true.
    Note

    If both spec.selector.labels and spec.selector.annotations fields are set, only namespaces that match both are selected.

The AAQ controller uses a scheduling gate mechanism to evaluate whether there is enough of a resource available to run a workload. If so, the scheduling gate is removed from the pod and it is considered ready for scheduling. The quota usage status is updated to indicate how much of the quota is used.

If the CPU and memory requests and limits for the workload exceed the enforced quota usage limit, the pod remains in SchedulingGated status until there is enough quota available. The AAQ controller creates an event of type Warning with details on why the quota was exceeded. You can view the event details by using the oc get events command.

Important

Pods that have the spec.nodeName field set to a specific node cannot use namespaces that match the spec.namespaceSelector labels defined in the HyperConverged CR.

7.14.2.2. Enabling the AAQ Operator

To deploy the AAQ Operator, set the enableApplicationAwareQuota feature gate to true in the HyperConverged custom resource (CR).

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.
  • You have installed the OpenShift CLI (oc).

Procedure

  • Set the enableApplicationAwareQuota feature gate to true in the HyperConverged CR by running the following command:

    $ oc patch hco kubevirt-hyperconverged -n openshift-cnv \
     --type json -p '[{"op": "add", "path": "/spec/featureGates/enableApplicationAwareQuota", "value": true}]'
7.14.2.3. Configuring the AAQ Operator by using the CLI

You can configure the AAQ Operator by specifying the fields of the spec.applicationAwareConfig object in the HyperConverged custom resource (CR).

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.
  • You have installed the OpenShift CLI (oc).

Procedure

  • Update the HyperConverged CR by running the following command:

    $ oc patch hco kubevirt-hyperconverged -n openshift-cnv --type merge -p '{
      "spec": {
        "applicationAwareConfig": {
          "vmiCalcConfigName": "DedicatedVirtualResources",
          "namespaceSelector": {
            "matchLabels": {
              "app": "my-app"
            }
          },
          "allowApplicationAwareClusterResourceQuota": true
        }
      }
    }'

    where:

    vmiCalcConfigName

    Specifies how resource counting is managed for pods that run virtual machine (VM) workloads. Possible values are:

    • VmiPodUsage: Counts compute resources for pods associated with VMs in the same way as native resource quotas and excludes migration-related resources.
    • VirtualResources: Counts compute resources based on the VM specifications, using the VM RAM size for memory and virtual CPUs for processing.
    • DedicatedVirtualResources (default): Similar to VirtualResources, but separates resource tracking for pods associated with VMs by adding a /vmi suffix to CPU and memory resource names. For example, requests.cpu/vmi and requests.memory/vmi.
    namespaceSelector
    Determines the namespaces for which an AAQ scheduling gate is added to pods when they are created. If a namespace selector is not defined, the AAQ Operator targets namespaces with the application-aware-quota/enable-gating label as default.
    allowApplicationAwareClusterResourceQuota
    If set to true, you can create and manage the ApplicationAwareClusterResourceQuota object. Setting this attribute to true can increase scheduling time.
7.14.2.4. Additional resources

7.14.3. Specifying nodes for virtual machines

You can place virtual machines (VMs) on specific nodes by using node placement rules.

7.14.3.1. About node placement for virtual machines

To ensure that virtual machines (VMs) run on appropriate nodes, you can configure node placement rules. You might want to do this if:

  • You have several VMs. To ensure fault tolerance, you want them to run on different nodes.
  • You have two chatty VMs. To avoid redundant inter-node routing, you want the VMs to run on the same node.
  • Your VMs require specific hardware features that are not present on all available nodes.
  • You have a pod that adds capabilities to a node, and you want to place a VM on that node so that it can use those capabilities.
Note

Virtual machine placement relies on any existing node placement rules for workloads. If workloads are excluded from specific nodes on the component level, virtual machines cannot be placed on those nodes.

You can use the following rule types in the spec field of a VirtualMachine manifest:

nodeSelector
Allows virtual machines to be scheduled on nodes that are labeled with the key-value pair or pairs that you specify in this field. The node must have labels that exactly match all listed pairs.
affinity
Enables you to use more expressive syntax to set rules that match nodes with virtual machines. For example, you can specify that a rule is a preference, rather than a hard requirement, so that virtual machines are still scheduled if the rule is not satisfied. Pod affinity, pod anti-affinity, and node affinity are supported for virtual machine placement. Pod affinity works for virtual machines because the VirtualMachine workload type is based on the Pod object.
tolerations

Allows virtual machines to be scheduled on nodes that have matching taints. If a taint is applied to a node, that node only accepts virtual machines that tolerate the taint.

Note

Affinity rules only apply during scheduling. OpenShift Container Platform does not reschedule running workloads if the constraints are no longer met.

7.14.3.2. Node placement examples

The following example YAML file snippets use nodePlacement, affinity, and tolerations fields to customize node placement for virtual machines.

7.14.3.2.1. Example: VM node placement with nodeSelector

In this example, the virtual machine requires a node that has metadata containing both example-key-1 = example-value-1 and example-key-2 = example-value-2 labels.

Warning

If there are no nodes that fit this description, the virtual machine is not scheduled.

Example VM manifest

metadata:
  name: example-vm-node-selector
apiVersion: kubevirt.io/v1
kind: VirtualMachine
spec:
  template:
    spec:
      nodeSelector:
        example-key-1: example-value-1
        example-key-2: example-value-2
# ...

7.14.3.2.2. Example: VM node placement with pod affinity and pod anti-affinity

In this example, the VM must be scheduled on a node that has a running pod with the label example-key-1 = example-value-1. If there is no such pod running on any node, the VM is not scheduled.

If possible, the VM is not scheduled on a node that has any pod with the label example-key-2 = example-value-2. However, if all candidate nodes have a pod with this label, the scheduler ignores this constraint.

Example VM manifest

metadata:
  name: example-vm-pod-affinity
apiVersion: kubevirt.io/v1
kind: VirtualMachine
spec:
  template:
    spec:
      affinity:
        podAffinity:
          requiredDuringSchedulingIgnoredDuringExecution: 1
          - labelSelector:
              matchExpressions:
              - key: example-key-1
                operator: In
                values:
                - example-value-1
            topologyKey: kubernetes.io/hostname
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution: 2
          - weight: 100
            podAffinityTerm:
              labelSelector:
                matchExpressions:
                - key: example-key-2
                  operator: In
                  values:
                  - example-value-2
              topologyKey: kubernetes.io/hostname
# ...

1
If you use the requiredDuringSchedulingIgnoredDuringExecution rule type, the VM is not scheduled if the constraint is not met.
2
If you use the preferredDuringSchedulingIgnoredDuringExecution rule type, the VM is still scheduled if the constraint is not met, as long as all required constraints are met.
7.14.3.2.3. Example: VM node placement with node affinity

In this example, the VM must be scheduled on a node that has the label example.io/example-key = example-value-1 or the label example.io/example-key = example-value-2. The constraint is met if only one of the labels is present on the node. If neither label is present, the VM is not scheduled.

If possible, the scheduler avoids nodes that have the label example-node-label-key = example-node-label-value. However, if all candidate nodes have this label, the scheduler ignores this constraint.

Example VM manifest

metadata:
  name: example-vm-node-affinity
apiVersion: kubevirt.io/v1
kind: VirtualMachine
spec:
  template:
    spec:
      affinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution: 1
            nodeSelectorTerms:
            - matchExpressions:
              - key: example.io/example-key
                operator: In
                values:
                - example-value-1
                - example-value-2
          preferredDuringSchedulingIgnoredDuringExecution: 2
          - weight: 1
            preference:
              matchExpressions:
              - key: example-node-label-key
                operator: In
                values:
                - example-node-label-value
# ...

1
If you use the requiredDuringSchedulingIgnoredDuringExecution rule type, the VM is not scheduled if the constraint is not met.
2
If you use the preferredDuringSchedulingIgnoredDuringExecution rule type, the VM is still scheduled if the constraint is not met, as long as all required constraints are met.
7.14.3.2.4. Example: VM node placement with tolerations

In this example, nodes that are reserved for virtual machines are already labeled with the key=virtualization:NoSchedule taint. Because this virtual machine has matching tolerations, it can schedule onto the tainted nodes.

Note

A virtual machine that tolerates a taint is not required to schedule onto a node with that taint.

Example VM manifest

metadata:
  name: example-vm-tolerations
apiVersion: kubevirt.io/v1
kind: VirtualMachine
spec:
  tolerations:
  - key: "key"
    operator: "Equal"
    value: "virtualization"
    effect: "NoSchedule"
# ...

7.14.3.3. Additional resources

7.14.4. Activating kernel samepage merging (KSM)

OpenShift Virtualization can activate kernel samepage merging (KSM) when nodes are overloaded. KSM deduplicates identical data found in the memory pages of virtual machines (VMs). If you have very similar VMs, KSM can make it possible to schedule more VMs on a single node.

Important

You must only use KSM with trusted workloads.

7.14.4.1. Prerequisites
  • Ensure that an administrator has configured KSM support on any nodes where you want OpenShift Virtualization to activate KSM.
7.14.4.2. About using OpenShift Virtualization to activate KSM

You can configure OpenShift Virtualization to activate kernel samepage merging (KSM) when nodes experience memory overload.

7.14.4.2.1. Configuration methods

You can enable or disable the KSM activation feature for all nodes by using the OpenShift Container Platform web console or by editing the HyperConverged custom resource (CR). The HyperConverged CR supports more granular configuration.

CR configuration

You can configure the KSM activation feature by editing the spec.configuration.ksmConfiguration stanza of the HyperConverged CR.

  • You enable the feature and configure settings by editing the ksmConfiguration stanza.
  • You disable the feature by deleting the ksmConfiguration stanza.
  • You can allow OpenShift Virtualization to enable KSM on only a subset of nodes by adding node selection syntax to the ksmConfiguration.nodeLabelSelector field.
Note

Even if the KSM activation feature is disabled in OpenShift Virtualization, an administrator can still enable KSM on nodes that support it.

7.14.4.2.2. KSM node labels

OpenShift Virtualization identifies nodes that are configured to support KSM and applies the following node labels:

kubevirt.io/ksm-handler-managed: "false"
This label is set to "true" when OpenShift Virtualization activates KSM on a node that is experiencing memory overload. This label is not set to "true" if an administrator activates KSM.
kubevirt.io/ksm-enabled: "false"
This label is set to "true" when KSM is activated on a node, even if OpenShift Virtualization did not activate KSM.

These labels are not applied to nodes that do not support KSM.

7.14.4.3. Configuring KSM activation by using the web console

You can allow OpenShift Virtualization to activate kernel samepage merging (KSM) on all nodes in your cluster by using the OpenShift Container Platform web console.

Procedure

  1. From the side menu, click VirtualizationOverview.
  2. Select the Settings tab.
  3. Select the Cluster tab.
  4. Expand Resource management.
  5. Enable or disable the feature for all nodes:

    • Set Kernel Samepage Merging (KSM) to on.
    • Set Kernel Samepage Merging (KSM) to off.
7.14.4.4. Configuring KSM activation by using the CLI

You can enable or disable OpenShift Virtualization’s kernel samepage merging (KSM) activation feature by editing the HyperConverged custom resource (CR). Use this method if you want OpenShift Virtualization to activate KSM on only a subset of nodes.

Procedure

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Edit the ksmConfiguration stanza:

    • To enable the KSM activation feature for all nodes, set the nodeLabelSelector value to {}. For example:

      apiVersion: hco.kubevirt.io/v1beta1
      kind: HyperConverged
      metadata:
        name: kubevirt-hyperconverged
        namespace: openshift-cnv
      spec:
        configuration:
          ksmConfiguration:
            nodeLabelSelector: {}
      # ...
    • To enable the KSM activation feature on a subset of nodes, edit the nodeLabelSelector field. Add syntax that matches the nodes where you want OpenShift Virtualization to enable KSM. For example, the following configuration allows OpenShift Virtualization to enable KSM on nodes where both <first_example_key> and <second_example_key> are set to "true":

      apiVersion: hco.kubevirt.io/v1beta1
      kind: HyperConverged
      metadata:
        name: kubevirt-hyperconverged
        namespace: openshift-cnv
      spec:
        configuration:
          ksmConfiguration:
            nodeLabelSelector:
              matchLabels:
                <first_example_key>: "true"
                <second_example_key>: "true"
      # ...
    • To disable the KSM activation feature, delete the ksmConfiguration stanza. For example:

      apiVersion: hco.kubevirt.io/v1beta1
      kind: HyperConverged
      metadata:
        name: kubevirt-hyperconverged
        namespace: openshift-cnv
      spec:
        configuration:
      # ...
  3. Save the file.
7.14.4.5. Additional resources

7.14.5. Configuring certificate rotation

Configure certificate rotation parameters to replace existing certificates.

7.14.5.1. Configuring certificate rotation

You can do this during OpenShift Virtualization installation in the web console or after installation in the HyperConverged custom resource (CR).

Procedure

  1. Open the HyperConverged CR by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Edit the spec.certConfig fields as shown in the following example. To avoid overloading the system, ensure that all values are greater than or equal to 10 minutes. Express all values as strings that comply with the golang ParseDuration format.

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      certConfig:
        ca:
          duration: 48h0m0s
          renewBefore: 24h0m0s 1
        server:
          duration: 24h0m0s  2
          renewBefore: 12h0m0s  3
    1
    The value of ca.renewBefore must be less than or equal to the value of ca.duration.
    2
    The value of server.duration must be less than or equal to the value of ca.duration.
    3
    The value of server.renewBefore must be less than or equal to the value of server.duration.
  3. Apply the YAML file to your cluster.
7.14.5.2. Troubleshooting certificate rotation parameters

Deleting one or more certConfig values causes them to revert to the default values, unless the default values conflict with one of the following conditions:

  • The value of ca.renewBefore must be less than or equal to the value of ca.duration.
  • The value of server.duration must be less than or equal to the value of ca.duration.
  • The value of server.renewBefore must be less than or equal to the value of server.duration.

If the default values conflict with these conditions, you will receive an error.

If you remove the server.duration value in the following example, the default value of 24h0m0s is greater than the value of ca.duration, conflicting with the specified conditions.

Example

certConfig:
   ca:
     duration: 4h0m0s
     renewBefore: 1h0m0s
   server:
     duration: 4h0m0s
     renewBefore: 4h0m0s

This results in the following error message:

error: hyperconvergeds.hco.kubevirt.io "kubevirt-hyperconverged" could not be patched: admission webhook "validate-hco.kubevirt.io" denied the request: spec.certConfig: ca.duration is smaller than server.duration

The error message only mentions the first conflict. Review all certConfig values before you proceed.

7.14.6. Configuring the default CPU model

Use the defaultCPUModel setting in the HyperConverged custom resource (CR) to define a cluster-wide default CPU model.

The virtual machine (VM) CPU model depends on the availability of CPU models within the VM and the cluster.

  • If the VM does not have a defined CPU model:

    • The defaultCPUModel is automatically set using the CPU model defined at the cluster-wide level.
  • If both the VM and the cluster have a defined CPU model:

    • The VM’s CPU model takes precedence.
  • If neither the VM nor the cluster have a defined CPU model:

    • The host-model is automatically set using the CPU model defined at the host level.
7.14.6.1. Configuring the default CPU model

Configure the defaultCPUModel by updating the HyperConverged custom resource (CR). You can change the defaultCPUModel while OpenShift Virtualization is running.

Note

The defaultCPUModel is case sensitive.

Prerequisites

  • Install the OpenShift CLI (oc).

Procedure

  1. Open the HyperConverged CR by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Add the defaultCPUModel field to the CR and set the value to the name of a CPU model that exists in the cluster:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
     name: kubevirt-hyperconverged
     namespace: openshift-cnv
    spec:
      defaultCPUModel: "EPYC"
  3. Apply the YAML file to your cluster.

7.14.7. Using UEFI mode for virtual machines

You can boot a virtual machine (VM) in Unified Extensible Firmware Interface (UEFI) mode.

7.14.7.1. About UEFI mode for virtual machines

Unified Extensible Firmware Interface (UEFI), like legacy BIOS, initializes hardware components and operating system image files when a computer starts. UEFI supports more modern features and customization options than BIOS, enabling faster boot times.

It stores all the information about initialization and startup in a file with a .efi extension, which is stored on a special partition called EFI System Partition (ESP). The ESP also contains the boot loader programs for the operating system that is installed on the computer.

7.14.7.2. Booting virtual machines in UEFI mode

You can configure a virtual machine to boot in UEFI mode by editing the VirtualMachine manifest.

Prerequisites

  • Install the OpenShift CLI (oc).

Procedure

  1. Edit or create a VirtualMachine manifest file. Use the spec.firmware.bootloader stanza to configure UEFI mode:

    Booting in UEFI mode with secure boot active

    apiversion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      labels:
        special: vm-secureboot
      name: vm-secureboot
    spec:
      template:
        metadata:
          labels:
            special: vm-secureboot
        spec:
          domain:
            devices:
              disks:
              - disk:
                  bus: virtio
                name: containerdisk
            features:
              acpi: {}
              smm:
                enabled: true 1
            firmware:
              bootloader:
                efi:
                  secureBoot: true 2
    # ...

    1
    OpenShift Virtualization requires System Management Mode (SMM) to be enabled for Secure Boot in UEFI mode to occur.
    2
    OpenShift Virtualization supports a VM with or without Secure Boot when using UEFI mode. If Secure Boot is enabled, then UEFI mode is required. However, UEFI mode can be enabled without using Secure Boot.
  2. Apply the manifest to your cluster by running the following command:

    $ oc create -f <file_name>.yaml
7.14.7.3. Enabling persistent EFI

You can enable EFI persistence in a VM by configuring an RWX storage class at the cluster level and adjusting the settings in the EFI section of the VM.

Prerequisites

  • You must have cluster administrator privileges.
  • You must have a storage class that supports RWX access mode and FS volume mode.

Procedure

  • Enable the VMPersistentState feature gate by running the following command:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
      --type json -p '[{"op":"replace","path":"/spec/featureGates/VMPersistentState", "value": true}]'
7.14.7.4. Configuring VMs with persistent EFI

You can configure a VM to have EFI persistence enabled by editing its manifest file.

Prerequisites

  • VMPersistentState feature gate enabled.

Procedure

  • Edit the VM manifest file and save to apply settings.

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm
    spec:
      template:
        spec:
          domain:
            firmware:
              bootloader:
                efi:
                  persistent: true
    # ...

7.14.8. Configuring PXE booting for virtual machines

PXE booting, or network booting, is available in OpenShift Virtualization. Network booting allows a computer to boot and load an operating system or other program without requiring a locally attached storage device. For example, you can use it to choose your desired OS image from a PXE server when deploying a new host.

7.14.8.1. Prerequisites
  • A Linux bridge must be connected.
  • The PXE server must be connected to the same VLAN as the bridge.
7.14.8.2. PXE booting with a specified MAC address

As an administrator, you can boot a client over the network by first creating a NetworkAttachmentDefinition object for your PXE network. Then, reference the network attachment definition in your virtual machine instance configuration file before you start the virtual machine instance. You can also specify a MAC address in the virtual machine instance configuration file, if required by the PXE server.

Prerequisites

  • A Linux bridge must be connected.
  • The PXE server must be connected to the same VLAN as the bridge.

Procedure

  1. Configure a PXE network on the cluster:

    1. Create the network attachment definition file for PXE network pxe-net-conf:

      apiVersion: "k8s.cni.cncf.io/v1"
      kind: NetworkAttachmentDefinition
      metadata:
        name: pxe-net-conf 1
      spec:
        config: |
          {
            "cniVersion": "0.3.1",
            "name": "pxe-net-conf", 2
            "type": "bridge", 3
            "bridge": "bridge-interface", 4
            "macspoofchk": false, 5
            "vlan": 100, 6
            "disableContainerInterface": true,
            "preserveDefaultVlan": false 7
          }
      1
      The name for the NetworkAttachmentDefinition object.
      2
      The name for the configuration. It is recommended to match the configuration name to the name value of the network attachment definition.
      3
      The actual name of the Container Network Interface (CNI) plugin that provides the network for this network attachment definition. This example uses a Linux bridge CNI plugin. You can also use an OVN-Kubernetes localnet or an SR-IOV CNI plugin.
      4
      The name of the Linux bridge configured on the node.
      5
      Optional: A flag to enable the MAC spoof check. When set to true, you cannot change the MAC address of the pod or guest interface. This attribute allows only a single MAC address to exit the pod, which provides security against a MAC spoofing attack.
      6
      Optional: The VLAN tag. No additional VLAN configuration is required on the node network configuration policy.
      7
      Optional: Indicates whether the VM connects to the bridge through the default VLAN. The default value is true.
  2. Create the network attachment definition by using the file you created in the previous step:

    $ oc create -f pxe-net-conf.yaml
  3. Edit the virtual machine instance configuration file to include the details of the interface and network.

    1. Specify the network and MAC address, if required by the PXE server. If the MAC address is not specified, a value is assigned automatically.

      Ensure that bootOrder is set to 1 so that the interface boots first. In this example, the interface is connected to a network called <pxe-net>:

      interfaces:
      - masquerade: {}
        name: default
      - bridge: {}
        name: pxe-net
        macAddress: de:00:00:00:00:de
        bootOrder: 1
      Note

      Boot order is global for interfaces and disks.

    2. Assign a boot device number to the disk to ensure proper booting after operating system provisioning.

      Set the disk bootOrder value to 2:

      devices:
        disks:
        - disk:
            bus: virtio
          name: containerdisk
          bootOrder: 2
    3. Specify that the network is connected to the previously created network attachment definition. In this scenario, <pxe-net> is connected to the network attachment definition called <pxe-net-conf>:

      networks:
      - name: default
        pod: {}
      - name: pxe-net
        multus:
          networkName: pxe-net-conf
  4. Create the virtual machine instance:

    $ oc create -f vmi-pxe-boot.yaml

    Example output

      virtualmachineinstance.kubevirt.io "vmi-pxe-boot" created

  5. Wait for the virtual machine instance to run:

    $ oc get vmi vmi-pxe-boot -o yaml | grep -i phase
      phase: Running
  6. View the virtual machine instance using VNC:

    $ virtctl vnc vmi-pxe-boot
  7. Watch the boot screen to verify that the PXE boot is successful.
  8. Log in to the virtual machine instance:

    $ virtctl console vmi-pxe-boot

Verification

  1. Verify the interfaces and MAC address on the virtual machine and that the interface connected to the bridge has the specified MAC address. In this case, we used eth1 for the PXE boot, without an IP address. The other interface, eth0, got an IP address from OpenShift Container Platform.

    $ ip addr

    Example output

    ...
    3. eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
       link/ether de:00:00:00:00:de brd ff:ff:ff:ff:ff:ff

7.14.8.3. OpenShift Virtualization networking glossary

The following terms are used throughout OpenShift Virtualization documentation:

Container Network Interface (CNI)
A Cloud Native Computing Foundation project, focused on container network connectivity. OpenShift Virtualization uses CNI plugins to build upon the basic Kubernetes networking functionality.
Multus
A "meta" CNI plugin that allows multiple CNIs to exist so that a pod or virtual machine can use the interfaces it needs.
Custom resource definition (CRD)
A Kubernetes API resource that allows you to define custom resources, or an object defined by using the CRD API resource.
Network attachment definition (NAD)
A CRD introduced by the Multus project that allows you to attach pods, virtual machines, and virtual machine instances to one or more networks.
Node network configuration policy (NNCP)
A CRD introduced by the nmstate project, describing the requested network configuration on nodes. You update the node network configuration, including adding and removing interfaces, by applying a NodeNetworkConfigurationPolicy manifest to the cluster.

7.14.9. Using huge pages with virtual machines

You can use huge pages as backing memory for virtual machines in your cluster.

7.14.9.1. Prerequisites
7.14.9.2. What huge pages do

Memory is managed in blocks known as pages. On most systems, a page is 4Ki. 1Mi of memory is equal to 256 pages; 1Gi of memory is 256,000 pages, and so on. CPUs have a built-in memory management unit that manages a list of these pages in hardware. The Translation Lookaside Buffer (TLB) is a small hardware cache of virtual-to-physical page mappings. If the virtual address passed in a hardware instruction can be found in the TLB, the mapping can be determined quickly. If not, a TLB miss occurs, and the system falls back to slower, software-based address translation, resulting in performance issues. Since the size of the TLB is fixed, the only way to reduce the chance of a TLB miss is to increase the page size.

A huge page is a memory page that is larger than 4Ki. On x86_64 architectures, there are two common huge page sizes: 2Mi and 1Gi. Sizes vary on other architectures. To use huge pages, code must be written so that applications are aware of them. Transparent Huge Pages (THP) attempt to automate the management of huge pages without application knowledge, but they have limitations. In particular, they are limited to 2Mi page sizes. THP can lead to performance degradation on nodes with high memory utilization or fragmentation due to defragmenting efforts of THP, which can lock memory pages. For this reason, some applications may be designed to (or recommend) usage of pre-allocated huge pages instead of THP.

In OpenShift Virtualization, virtual machines can be configured to consume pre-allocated huge pages.

7.14.9.3. Configuring huge pages for virtual machines

You can configure virtual machines to use pre-allocated huge pages by including the memory.hugepages.pageSize and resources.requests.memory parameters in your virtual machine configuration.

The memory request must be divisible by the page size. For example, you cannot request 500Mi memory with a page size of 1Gi.

Note

The memory layouts of the host and the guest OS are unrelated. Huge pages requested in the virtual machine manifest apply to QEMU. Huge pages inside the guest can only be configured based on the amount of available memory of the virtual machine instance.

If you edit a running virtual machine, the virtual machine must be rebooted for the changes to take effect.

Prerequisites

  • Nodes must have pre-allocated huge pages configured.

Procedure

  1. In your virtual machine configuration, add the resources.requests.memory and memory.hugepages.pageSize parameters to the spec.domain. The following configuration snippet is for a virtual machine that requests a total of 4Gi memory with a page size of 1Gi:

    kind: VirtualMachine
    # ...
    spec:
      domain:
        resources:
          requests:
            memory: "4Gi" 1
        memory:
          hugepages:
            pageSize: "1Gi" 2
    # ...
    1
    The total amount of memory requested for the virtual machine. This value must be divisible by the page size.
    2
    The size of each huge page. Valid values for x86_64 architecture are 1Gi and 2Mi. The page size must be smaller than the requested memory.
  2. Apply the virtual machine configuration:

    $ oc apply -f <virtual_machine>.yaml

7.14.10. Enabling dedicated resources for virtual machines

To improve performance, you can dedicate node resources, such as CPU, to a virtual machine.

7.14.10.1. About dedicated resources

When you enable dedicated resources for your virtual machine, your virtual machine’s workload is scheduled on CPUs that will not be used by other processes. By using dedicated resources, you can improve the performance of the virtual machine and the accuracy of latency predictions.

7.14.10.2. Prerequisites
  • The CPU Manager must be configured on the node. Verify that the node has the cpumanager = true label before scheduling virtual machine workloads.
  • The virtual machine must be powered off.
7.14.10.3. Enabling dedicated resources for a virtual machine

You enable dedicated resources for a virtual machine in the Details tab. Virtual machines that were created from a Red Hat template can be configured with dedicated resources.

Procedure

  1. In the OpenShift Container Platform console, click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. On the Configuration → Scheduling tab, click the edit icon beside Dedicated Resources.
  4. Select Schedule this workload with dedicated resources (guaranteed policy).
  5. Click Save.

7.14.11. Scheduling virtual machines

You can schedule a virtual machine (VM) on a node by ensuring that the VM’s CPU model and policy attribute are matched for compatibility with the CPU models and policy attributes supported by the node.

7.14.11.1. Policy attributes

You can schedule a virtual machine (VM) by specifying a policy attribute and a CPU feature that is matched for compatibility when the VM is scheduled on a node. A policy attribute specified for a VM determines how that VM is scheduled on a node.

Policy attributeDescription

force

The VM is forced to be scheduled on a node. This is true even if the host CPU does not support the VM’s CPU.

require

Default policy that applies to a VM if the VM is not configured with a specific CPU model and feature specification. If a node is not configured to support CPU node discovery with this default policy attribute or any one of the other policy attributes, VMs are not scheduled on that node. Either the host CPU must support the VM’s CPU or the hypervisor must be able to emulate the supported CPU model.

optional

The VM is added to a node if that VM is supported by the host’s physical machine CPU.

disable

The VM cannot be scheduled with CPU node discovery.

forbid

The VM is not scheduled even if the feature is supported by the host CPU and CPU node discovery is enabled.

7.14.11.2. Setting a policy attribute and CPU feature

You can set a policy attribute and CPU feature for each virtual machine (VM) to ensure that it is scheduled on a node according to policy and feature. The CPU feature that you set is verified to ensure that it is supported by the host CPU or emulated by the hypervisor.

Procedure

  • Edit the domain spec of your VM configuration file. The following example sets the CPU feature and the require policy for a virtual machine (VM):

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: myvm
    spec:
      template:
        spec:
          domain:
            cpu:
              features:
                - name: apic 1
                  policy: require 2
    1
    Name of the CPU feature for the VM.
    2
    Policy attribute for the VM.
7.14.11.3. Scheduling virtual machines with the supported CPU model

You can configure a CPU model for a virtual machine (VM) to schedule it on a node where its CPU model is supported.

Procedure

  • Edit the domain spec of your virtual machine configuration file. The following example shows a specific CPU model defined for a VM:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: myvm
    spec:
      template:
        spec:
          domain:
            cpu:
              model: Conroe 1
    1
    CPU model for the VM.
7.14.11.4. Scheduling virtual machines with the host model

When the CPU model for a virtual machine (VM) is set to host-model, the VM inherits the CPU model of the node where it is scheduled.

Procedure

  • Edit the domain spec of your VM configuration file. The following example shows host-model being specified for the virtual machine:

    apiVersion: kubevirt/v1alpha3
    kind: VirtualMachine
    metadata:
      name: myvm
    spec:
      template:
        spec:
          domain:
            cpu:
              model: host-model 1
    1
    The VM that inherits the CPU model of the node where it is scheduled.
7.14.11.5. Scheduling virtual machines with a custom scheduler

You can use a custom scheduler to schedule a virtual machine (VM) on a node.

Prerequisites

  • A secondary scheduler is configured for your cluster.

Procedure

  • Add the custom scheduler to the VM configuration by editing the VirtualMachine manifest. For example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-fedora
    spec:
      running: true
      template:
        spec:
          schedulerName: my-scheduler 1
          domain:
            devices:
              disks:
                - name: containerdisk
                  disk:
                    bus: virtio
    # ...
    1
    The name of the custom scheduler. If the schedulerName value does not match an existing scheduler, the virt-launcher pod stays in a Pending state until the specified scheduler is found.

Verification

  • Verify that the VM is using the custom scheduler specified in the VirtualMachine manifest by checking the virt-launcher pod events:

    1. View the list of pods in your cluster by entering the following command:

      $ oc get pods

      Example output

      NAME                             READY   STATUS    RESTARTS   AGE
      virt-launcher-vm-fedora-dpc87    2/2     Running   0          24m

    2. Run the following command to display the pod events:

      $ oc describe pod virt-launcher-vm-fedora-dpc87

      The value of the From field in the output verifies that the scheduler name matches the custom scheduler specified in the VirtualMachine manifest:

      Example output

      [...]
      Events:
        Type    Reason     Age   From              Message
        ----    ------     ----  ----              -------
        Normal  Scheduled  21m   my-scheduler  Successfully assigned default/virt-launcher-vm-fedora-dpc87 to node01
      [...]

Additional resources

7.14.12. Configuring PCI passthrough

The Peripheral Component Interconnect (PCI) passthrough feature enables you to access and manage hardware devices from a virtual machine (VM). When PCI passthrough is configured, the PCI devices function as if they were physically attached to the guest operating system.

Cluster administrators can expose and manage host devices that are permitted to be used in the cluster by using the oc command-line interface (CLI).

7.14.12.1. Preparing nodes for GPU passthrough

You can prevent GPU operands from deploying on worker nodes that you designated for GPU passthrough.

7.14.12.1.1. Preventing NVIDIA GPU operands from deploying on nodes

If you use the NVIDIA GPU Operator in your cluster, you can apply the nvidia.com/gpu.deploy.operands=false label to nodes that you do not want to configure for GPU or vGPU operands. This label prevents the creation of the pods that configure GPU or vGPU operands and terminates the pods if they already exist.

Prerequisites

  • The OpenShift CLI (oc) is installed.

Procedure

  • Label the node by running the following command:

    $ oc label node <node_name> nvidia.com/gpu.deploy.operands=false 1
    1
    Replace <node_name> with the name of a node where you do not want to install the NVIDIA GPU operands.

Verification

  1. Verify that the label was added to the node by running the following command:

    $ oc describe node <node_name>
  2. Optional: If GPU operands were previously deployed on the node, verify their removal.

    1. Check the status of the pods in the nvidia-gpu-operator namespace by running the following command:

      $ oc get pods -n nvidia-gpu-operator

      Example output

      NAME                             READY   STATUS        RESTARTS   AGE
      gpu-operator-59469b8c5c-hw9wj    1/1     Running       0          8d
      nvidia-sandbox-validator-7hx98   1/1     Running       0          8d
      nvidia-sandbox-validator-hdb7p   1/1     Running       0          8d
      nvidia-sandbox-validator-kxwj7   1/1     Terminating   0          9d
      nvidia-vfio-manager-7w9fs        1/1     Running       0          8d
      nvidia-vfio-manager-866pz        1/1     Running       0          8d
      nvidia-vfio-manager-zqtck        1/1     Terminating   0          9d

    2. Monitor the pod status until the pods with Terminating status are removed:

      $ oc get pods -n nvidia-gpu-operator

      Example output

      NAME                             READY   STATUS    RESTARTS   AGE
      gpu-operator-59469b8c5c-hw9wj    1/1     Running   0          8d
      nvidia-sandbox-validator-7hx98   1/1     Running   0          8d
      nvidia-sandbox-validator-hdb7p   1/1     Running   0          8d
      nvidia-vfio-manager-7w9fs        1/1     Running   0          8d
      nvidia-vfio-manager-866pz        1/1     Running   0          8d

7.14.12.2. Preparing host devices for PCI passthrough
7.14.12.2.1. About preparing a host device for PCI passthrough

To prepare a host device for PCI passthrough by using the CLI, create a MachineConfig object and add kernel arguments to enable the Input-Output Memory Management Unit (IOMMU). Bind the PCI device to the Virtual Function I/O (VFIO) driver and then expose it in the cluster by editing the permittedHostDevices field of the HyperConverged custom resource (CR). The permittedHostDevices list is empty when you first install the OpenShift Virtualization Operator.

To remove a PCI host device from the cluster by using the CLI, delete the PCI device information from the HyperConverged CR.

7.14.12.2.2. Adding kernel arguments to enable the IOMMU driver

To enable the IOMMU driver in the kernel, create the MachineConfig object and add the kernel arguments.

Prerequisites

  • You have cluster administrator permissions.
  • Your CPU hardware is Intel or AMD.
  • You enabled Intel Virtualization Technology for Directed I/O extensions or AMD IOMMU in the BIOS.

Procedure

  1. Create a MachineConfig object that identifies the kernel argument. The following example shows a kernel argument for an Intel CPU.

    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    metadata:
      labels:
        machineconfiguration.openshift.io/role: worker 1
      name: 100-worker-iommu 2
    spec:
      config:
        ignition:
          version: 3.2.0
      kernelArguments:
          - intel_iommu=on 3
    # ...
    1
    Applies the new kernel argument only to worker nodes.
    2
    The name indicates the ranking of this kernel argument (100) among the machine configs and its purpose. If you have an AMD CPU, specify the kernel argument as amd_iommu=on.
    3
    Identifies the kernel argument as intel_iommu for an Intel CPU.
  2. Create the new MachineConfig object:

    $ oc create -f 100-worker-kernel-arg-iommu.yaml

Verification

  • Verify that the new MachineConfig object was added.

    $ oc get MachineConfig
7.14.12.2.3. Binding PCI devices to the VFIO driver

To bind PCI devices to the VFIO (Virtual Function I/O) driver, obtain the values for vendor-ID and device-ID from each device and create a list with the values. Add this list to the MachineConfig object. The MachineConfig Operator generates the /etc/modprobe.d/vfio.conf on the nodes with the PCI devices, and binds the PCI devices to the VFIO driver.

Prerequisites

  • You added kernel arguments to enable IOMMU for the CPU.

Procedure

  1. Run the lspci command to obtain the vendor-ID and the device-ID for the PCI device.

    $ lspci -nnv | grep -i nvidia

    Example output

    02:01.0 3D controller [0302]: NVIDIA Corporation GV100GL [Tesla V100 PCIe 32GB] [10de:1eb8] (rev a1)

  2. Create a Butane config file, 100-worker-vfiopci.bu, binding the PCI device to the VFIO driver.

    Note

    See "Creating machine configs with Butane" for information about Butane.

    Example

    variant: openshift
    version: 4.17.0
    metadata:
      name: 100-worker-vfiopci
      labels:
        machineconfiguration.openshift.io/role: worker 1
    storage:
      files:
      - path: /etc/modprobe.d/vfio.conf
        mode: 0644
        overwrite: true
        contents:
          inline: |
            options vfio-pci ids=10de:1eb8 2
      - path: /etc/modules-load.d/vfio-pci.conf 3
        mode: 0644
        overwrite: true
        contents:
          inline: vfio-pci

    1
    Applies the new kernel argument only to worker nodes.
    2
    Specify the previously determined vendor-ID value (10de) and the device-ID value (1eb8) to bind a single device to the VFIO driver. You can add a list of multiple devices with their vendor and device information.
    3
    The file that loads the vfio-pci kernel module on the worker nodes.
  3. Use Butane to generate a MachineConfig object file, 100-worker-vfiopci.yaml, containing the configuration to be delivered to the worker nodes:

    $ butane 100-worker-vfiopci.bu -o 100-worker-vfiopci.yaml
  4. Apply the MachineConfig object to the worker nodes:

    $ oc apply -f 100-worker-vfiopci.yaml
  5. Verify that the MachineConfig object was added.

    $ oc get MachineConfig

    Example output

    NAME                             GENERATEDBYCONTROLLER                      IGNITIONVERSION  AGE
    00-master                        d3da910bfa9f4b599af4ed7f5ac270d55950a3a1   3.2.0            25h
    00-worker                        d3da910bfa9f4b599af4ed7f5ac270d55950a3a1   3.2.0            25h
    01-master-container-runtime      d3da910bfa9f4b599af4ed7f5ac270d55950a3a1   3.2.0            25h
    01-master-kubelet                d3da910bfa9f4b599af4ed7f5ac270d55950a3a1   3.2.0            25h
    01-worker-container-runtime      d3da910bfa9f4b599af4ed7f5ac270d55950a3a1   3.2.0            25h
    01-worker-kubelet                d3da910bfa9f4b599af4ed7f5ac270d55950a3a1   3.2.0            25h
    100-worker-iommu                                                            3.2.0            30s
    100-worker-vfiopci-configuration                                            3.2.0            30s

Verification

  • Verify that the VFIO driver is loaded.

    $ lspci -nnk -d 10de:

    The output confirms that the VFIO driver is being used.

    Example output

    04:00.0 3D controller [0302]: NVIDIA Corporation GP102GL [Tesla P40] [10de:1eb8] (rev a1)
            Subsystem: NVIDIA Corporation Device [10de:1eb8]
            Kernel driver in use: vfio-pci
            Kernel modules: nouveau

7.14.12.2.4. Exposing PCI host devices in the cluster using the CLI

To expose PCI host devices in the cluster, add details about the PCI devices to the spec.permittedHostDevices.pciHostDevices array of the HyperConverged custom resource (CR).

Procedure

  1. Edit the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Add the PCI device information to the spec.permittedHostDevices.pciHostDevices array. For example:

    Example configuration file

    apiVersion: hco.kubevirt.io/v1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      permittedHostDevices: 1
        pciHostDevices: 2
        - pciDeviceSelector: "10DE:1DB6" 3
          resourceName: "nvidia.com/GV100GL_Tesla_V100" 4
        - pciDeviceSelector: "10DE:1EB8"
          resourceName: "nvidia.com/TU104GL_Tesla_T4"
        - pciDeviceSelector: "8086:6F54"
          resourceName: "intel.com/qat"
          externalResourceProvider: true 5
    # ...

    1
    The host devices that are permitted to be used in the cluster.
    2
    The list of PCI devices available on the node.
    3
    The vendor-ID and the device-ID required to identify the PCI device.
    4
    The name of a PCI host device.
    5
    Optional: Setting this field to true indicates that the resource is provided by an external device plugin. OpenShift Virtualization allows the usage of this device in the cluster but leaves the allocation and monitoring to an external device plugin.
    Note

    The above example snippet shows two PCI host devices that are named nvidia.com/GV100GL_Tesla_V100 and nvidia.com/TU104GL_Tesla_T4 added to the list of permitted host devices in the HyperConverged CR. These devices have been tested and verified to work with OpenShift Virtualization.

  3. Save your changes and exit the editor.

Verification

  • Verify that the PCI host devices were added to the node by running the following command. The example output shows that there is one device each associated with the nvidia.com/GV100GL_Tesla_V100, nvidia.com/TU104GL_Tesla_T4, and intel.com/qat resource names.

    $ oc describe node <node_name>

    Example output

    Capacity:
      cpu:                            64
      devices.kubevirt.io/kvm:        110
      devices.kubevirt.io/tun:        110
      devices.kubevirt.io/vhost-net:  110
      ephemeral-storage:              915128Mi
      hugepages-1Gi:                  0
      hugepages-2Mi:                  0
      memory:                         131395264Ki
      nvidia.com/GV100GL_Tesla_V100   1
      nvidia.com/TU104GL_Tesla_T4     1
      intel.com/qat:                  1
      pods:                           250
    Allocatable:
      cpu:                            63500m
      devices.kubevirt.io/kvm:        110
      devices.kubevirt.io/tun:        110
      devices.kubevirt.io/vhost-net:  110
      ephemeral-storage:              863623130526
      hugepages-1Gi:                  0
      hugepages-2Mi:                  0
      memory:                         130244288Ki
      nvidia.com/GV100GL_Tesla_V100   1
      nvidia.com/TU104GL_Tesla_T4     1
      intel.com/qat:                  1
      pods:                           250

7.14.12.2.5. Removing PCI host devices from the cluster using the CLI

To remove a PCI host device from the cluster, delete the information for that device from the HyperConverged custom resource (CR).

Procedure

  1. Edit the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Remove the PCI device information from the spec.permittedHostDevices.pciHostDevices array by deleting the pciDeviceSelector, resourceName and externalResourceProvider (if applicable) fields for the appropriate device. In this example, the intel.com/qat resource has been deleted.

    Example configuration file

    apiVersion: hco.kubevirt.io/v1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      permittedHostDevices:
        pciHostDevices:
        - pciDeviceSelector: "10DE:1DB6"
          resourceName: "nvidia.com/GV100GL_Tesla_V100"
        - pciDeviceSelector: "10DE:1EB8"
          resourceName: "nvidia.com/TU104GL_Tesla_T4"
    # ...

  3. Save your changes and exit the editor.

Verification

  • Verify that the PCI host device was removed from the node by running the following command. The example output shows that there are zero devices associated with the intel.com/qat resource name.

    $ oc describe node <node_name>

    Example output

    Capacity:
      cpu:                            64
      devices.kubevirt.io/kvm:        110
      devices.kubevirt.io/tun:        110
      devices.kubevirt.io/vhost-net:  110
      ephemeral-storage:              915128Mi
      hugepages-1Gi:                  0
      hugepages-2Mi:                  0
      memory:                         131395264Ki
      nvidia.com/GV100GL_Tesla_V100   1
      nvidia.com/TU104GL_Tesla_T4     1
      intel.com/qat:                  0
      pods:                           250
    Allocatable:
      cpu:                            63500m
      devices.kubevirt.io/kvm:        110
      devices.kubevirt.io/tun:        110
      devices.kubevirt.io/vhost-net:  110
      ephemeral-storage:              863623130526
      hugepages-1Gi:                  0
      hugepages-2Mi:                  0
      memory:                         130244288Ki
      nvidia.com/GV100GL_Tesla_V100   1
      nvidia.com/TU104GL_Tesla_T4     1
      intel.com/qat:                  0
      pods:                           250

7.14.12.3. Configuring virtual machines for PCI passthrough

After the PCI devices have been added to the cluster, you can assign them to virtual machines. The PCI devices are now available as if they are physically connected to the virtual machines.

7.14.12.3.1. Assigning a PCI device to a virtual machine

When a PCI device is available in a cluster, you can assign it to a virtual machine and enable PCI passthrough.

Procedure

  • Assign the PCI device to a virtual machine as a host device.

    Example

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    spec:
      domain:
        devices:
          hostDevices:
          - deviceName: nvidia.com/TU104GL_Tesla_T4 1
            name: hostdevices1

    1
    The name of the PCI device that is permitted on the cluster as a host device. The virtual machine can access this host device.

Verification

  • Use the following command to verify that the host device is available from the virtual machine.

    $ lspci -nnk | grep NVIDIA

    Example output

    $ 02:01.0 3D controller [0302]: NVIDIA Corporation GV100GL [Tesla V100 PCIe 32GB] [10de:1eb8] (rev a1)

7.14.12.4. Additional resources

7.14.13. Configuring virtual GPUs

If you have graphics processing unit (GPU) cards, OpenShift Virtualization can automatically create virtual GPUs (vGPUs) that you can assign to virtual machines (VMs).

7.14.13.1. About using virtual GPUs with OpenShift Virtualization

Some graphics processing unit (GPU) cards support the creation of virtual GPUs (vGPUs). OpenShift Virtualization can automatically create vGPUs and other mediated devices if an administrator provides configuration details in the HyperConverged custom resource (CR). This automation is especially useful for large clusters.

Note

Refer to your hardware vendor’s documentation for functionality and support details.

Mediated device
A physical device that is divided into one or more virtual devices. A vGPU is a type of mediated device (mdev); the performance of the physical GPU is divided among the virtual devices. You can assign mediated devices to one or more virtual machines (VMs), but the number of guests must be compatible with your GPU. Some GPUs do not support multiple guests.
7.14.13.2. Preparing hosts for mediated devices

You must enable the Input-Output Memory Management Unit (IOMMU) driver before you can configure mediated devices.

7.14.13.2.1. Adding kernel arguments to enable the IOMMU driver

To enable the IOMMU driver in the kernel, create the MachineConfig object and add the kernel arguments.

Prerequisites

  • You have cluster administrator permissions.
  • Your CPU hardware is Intel or AMD.
  • You enabled Intel Virtualization Technology for Directed I/O extensions or AMD IOMMU in the BIOS.

Procedure

  1. Create a MachineConfig object that identifies the kernel argument. The following example shows a kernel argument for an Intel CPU.

    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    metadata:
      labels:
        machineconfiguration.openshift.io/role: worker 1
      name: 100-worker-iommu 2
    spec:
      config:
        ignition:
          version: 3.2.0
      kernelArguments:
          - intel_iommu=on 3
    # ...
    1
    Applies the new kernel argument only to worker nodes.
    2
    The name indicates the ranking of this kernel argument (100) among the machine configs and its purpose. If you have an AMD CPU, specify the kernel argument as amd_iommu=on.
    3
    Identifies the kernel argument as intel_iommu for an Intel CPU.
  2. Create the new MachineConfig object:

    $ oc create -f 100-worker-kernel-arg-iommu.yaml

Verification

  • Verify that the new MachineConfig object was added.

    $ oc get MachineConfig
7.14.13.3. Configuring the NVIDIA GPU Operator

You can use the NVIDIA GPU Operator to provision worker nodes for running GPU-accelerated virtual machines (VMs) in OpenShift Virtualization.

Note

The NVIDIA GPU Operator is supported only by NVIDIA. For more information, see Obtaining Support from NVIDIA in the Red Hat Knowledgebase.

7.14.13.3.1. About using the NVIDIA GPU Operator

You can use the NVIDIA GPU Operator with OpenShift Virtualization to rapidly provision worker nodes for running GPU-enabled virtual machines (VMs). The NVIDIA GPU Operator manages NVIDIA GPU resources in an OpenShift Container Platform cluster and automates tasks that are required when preparing nodes for GPU workloads.

Before you can deploy application workloads to a GPU resource, you must install components such as the NVIDIA drivers that enable the compute unified device architecture (CUDA), Kubernetes device plugin, container runtime, and other features, such as automatic node labeling and monitoring. By automating these tasks, you can quickly scale the GPU capacity of your infrastructure. The NVIDIA GPU Operator can especially facilitate provisioning complex artificial intelligence and machine learning (AI/ML) workloads.

7.14.13.3.2. Options for configuring mediated devices

There are two available methods for configuring mediated devices when using the NVIDIA GPU Operator. The method that Red Hat tests uses OpenShift Virtualization features to schedule mediated devices, while the NVIDIA method only uses the GPU Operator.

Using the NVIDIA GPU Operator to configure mediated devices
This method exclusively uses the NVIDIA GPU Operator to configure mediated devices. To use this method, refer to NVIDIA GPU Operator with OpenShift Virtualization in the NVIDIA documentation.
Using OpenShift Virtualization to configure mediated devices

This method, which is tested by Red Hat, uses OpenShift Virtualization’s capabilities to configure mediated devices. In this case, the NVIDIA GPU Operator is only used for installing drivers with the NVIDIA vGPU Manager. The GPU Operator does not configure mediated devices.

When using the OpenShift Virtualization method, you still configure the GPU Operator by following the NVIDIA documentation. However, this method differs from the NVIDIA documentation in the following ways:

  • You must not overwrite the default disableMDEVConfiguration: false setting in the HyperConverged custom resource (CR).

    Important

    Setting this feature gate as described in the NVIDIA documentation prevents OpenShift Virtualization from configuring mediated devices.

  • You must configure your ClusterPolicy manifest so that it matches the following example:

    Example manifest

    kind: ClusterPolicy
    apiVersion: nvidia.com/v1
    metadata:
      name: gpu-cluster-policy
    spec:
      operator:
        defaultRuntime: crio
        use_ocp_driver_toolkit: true
        initContainer: {}
      sandboxWorkloads:
        enabled: true
        defaultWorkload: vm-vgpu
      driver:
        enabled: false 1
      dcgmExporter: {}
      dcgm:
        enabled: true
      daemonsets: {}
      devicePlugin: {}
      gfd: {}
      migManager:
        enabled: true
      nodeStatusExporter:
        enabled: true
      mig:
        strategy: single
      toolkit:
        enabled: true
      validator:
        plugin:
          env:
            - name: WITH_WORKLOAD
              value: "true"
      vgpuManager:
        enabled: true 2
        repository: <vgpu_container_registry> 3
        image: <vgpu_image_name>
        version: nvidia-vgpu-manager
      vgpuDeviceManager:
        enabled: false 4
        config:
          name: vgpu-devices-config
          default: default
      sandboxDevicePlugin:
        enabled: false 5
      vfioManager:
        enabled: false 6

    1
    Set this value to false. Not required for VMs.
    2
    Set this value to true. Required for using vGPUs with VMs.
    3
    Substitute <vgpu_container_registry> with your registry value.
    4
    Set this value to false to allow OpenShift Virtualization to configure mediated devices instead of the NVIDIA GPU Operator.
    5
    Set this value to false to prevent discovery and advertising of the vGPU devices to the kubelet.
    6
    Set this value to false to prevent loading the vfio-pci driver. Instead, follow the OpenShift Virtualization documentation to configure PCI passthrough.

Additional resources

7.14.13.4. How vGPUs are assigned to nodes

For each physical device, OpenShift Virtualization configures the following values:

  • A single mdev type.
  • The maximum number of instances of the selected mdev type.

The cluster architecture affects how devices are created and assigned to nodes.

Large cluster with multiple cards per node

On nodes with multiple cards that can support similar vGPU types, the relevant device types are created in a round-robin manner. For example:

# ...
mediatedDevicesConfiguration:
  mediatedDeviceTypes:
  - nvidia-222
  - nvidia-228
  - nvidia-105
  - nvidia-108
# ...

In this scenario, each node has two cards, both of which support the following vGPU types:

nvidia-105
# ...
nvidia-108
nvidia-217
nvidia-299
# ...

On each node, OpenShift Virtualization creates the following vGPUs:

  • 16 vGPUs of type nvidia-105 on the first card.
  • 2 vGPUs of type nvidia-108 on the second card.
One node has a single card that supports more than one requested vGPU type

OpenShift Virtualization uses the supported type that comes first on the mediatedDeviceTypes list.

For example, the card on a node card supports nvidia-223 and nvidia-224. The following mediatedDeviceTypes list is configured:

# ...
mediatedDevicesConfiguration:
  mediatedDeviceTypes:
  - nvidia-22
  - nvidia-223
  - nvidia-224
# ...

In this example, OpenShift Virtualization uses the nvidia-223 type.

7.14.13.5. Managing mediated devices

Before you can assign mediated devices to virtual machines, you must create the devices and expose them to the cluster. You can also reconfigure and remove mediated devices.

7.14.13.5.1. Creating and exposing mediated devices

As an administrator, you can create mediated devices and expose them to the cluster by editing the HyperConverged custom resource (CR).

Prerequisites

  • You enabled the Input-Output Memory Management Unit (IOMMU) driver.
  • If your hardware vendor provides drivers, you installed them on the nodes where you want to create mediated devices.

Procedure

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

    Example 7.1. Example configuration file with mediated devices configured

    apiVersion: hco.kubevirt.io/v1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      mediatedDevicesConfiguration:
        mediatedDeviceTypes:
        - nvidia-231
        nodeMediatedDeviceTypes:
        - mediatedDeviceTypes:
          - nvidia-233
          nodeSelector:
            kubernetes.io/hostname: node-11.redhat.com
      permittedHostDevices:
        mediatedDevices:
        - mdevNameSelector: GRID T4-2Q
          resourceName: nvidia.com/GRID_T4-2Q
        - mdevNameSelector: GRID T4-8Q
          resourceName: nvidia.com/GRID_T4-8Q
    # ...
  2. Create mediated devices by adding them to the spec.mediatedDevicesConfiguration stanza:

    Example YAML snippet

    # ...
    spec:
      mediatedDevicesConfiguration:
        mediatedDeviceTypes: 1
        - <device_type>
        nodeMediatedDeviceTypes: 2
        - mediatedDeviceTypes: 3
          - <device_type>
          nodeSelector: 4
            <node_selector_key>: <node_selector_value>
    # ...

    1
    Required: Configures global settings for the cluster.
    2
    Optional: Overrides the global configuration for a specific node or group of nodes. Must be used with the global mediatedDeviceTypes configuration.
    3
    Required if you use nodeMediatedDeviceTypes. Overrides the global mediatedDeviceTypes configuration for the specified nodes.
    4
    Required if you use nodeMediatedDeviceTypes. Must include a key:value pair.
    Important

    Before OpenShift Virtualization 4.14, the mediatedDeviceTypes field was named mediatedDevicesTypes. Ensure that you use the correct field name when configuring mediated devices.

  3. Identify the name selector and resource name values for the devices that you want to expose to the cluster. You will add these values to the HyperConverged CR in the next step.

    1. Find the resourceName value by running the following command:

      $ oc get $NODE -o json \
        | jq '.status.allocatable \
          | with_entries(select(.key | startswith("nvidia.com/"))) \
          | with_entries(select(.value != "0"))'
    2. Find the mdevNameSelector value by viewing the contents of /sys/bus/pci/devices/<slot>:<bus>:<domain>.<function>/mdev_supported_types/<type>/name, substituting the correct values for your system.

      For example, the name file for the nvidia-231 type contains the selector string GRID T4-2Q. Using GRID T4-2Q as the mdevNameSelector value allows nodes to use the nvidia-231 type.

  4. Expose the mediated devices to the cluster by adding the mdevNameSelector and resourceName values to the spec.permittedHostDevices.mediatedDevices stanza of the HyperConverged CR:

    Example YAML snippet

    # ...
      permittedHostDevices:
        mediatedDevices:
        - mdevNameSelector: GRID T4-2Q 1
          resourceName: nvidia.com/GRID_T4-2Q 2
    # ...

    1
    Exposes the mediated devices that map to this value on the host.
    2
    Matches the resource name that is allocated on the node.
  5. Save your changes and exit the editor.

Verification

  • Optional: Confirm that a device was added to a specific node by running the following command:

    $ oc describe node <node_name>
7.14.13.5.2. About changing and removing mediated devices

You can reconfigure or remove mediated devices in several ways:

  • Edit the HyperConverged CR and change the contents of the mediatedDeviceTypes stanza.
  • Change the node labels that match the nodeMediatedDeviceTypes node selector.
  • Remove the device information from the spec.mediatedDevicesConfiguration and spec.permittedHostDevices stanzas of the HyperConverged CR.

    Note

    If you remove the device information from the spec.permittedHostDevices stanza without also removing it from the spec.mediatedDevicesConfiguration stanza, you cannot create a new mediated device type on the same node. To properly remove mediated devices, remove the device information from both stanzas.

7.14.13.5.3. Removing mediated devices from the cluster

To remove a mediated device from the cluster, delete the information for that device from the HyperConverged custom resource (CR).

Procedure

  1. Edit the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Remove the device information from the spec.mediatedDevicesConfiguration and spec.permittedHostDevices stanzas of the HyperConverged CR. Removing both entries ensures that you can later create a new mediated device type on the same node. For example:

    Example configuration file

    apiVersion: hco.kubevirt.io/v1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      mediatedDevicesConfiguration:
        mediatedDeviceTypes: 1
          - nvidia-231
      permittedHostDevices:
        mediatedDevices: 2
        - mdevNameSelector: GRID T4-2Q
          resourceName: nvidia.com/GRID_T4-2Q

    1
    To remove the nvidia-231 device type, delete it from the mediatedDeviceTypes array.
    2
    To remove the GRID T4-2Q device, delete the mdevNameSelector field and its corresponding resourceName field.
  3. Save your changes and exit the editor.
7.14.13.6. Using mediated devices

You can assign mediated devices to one or more virtual machines.

7.14.13.6.1. Assigning a vGPU to a VM by using the CLI

Assign mediated devices such as virtual GPUs (vGPUs) to virtual machines (VMs).

Prerequisites

  • The mediated device is configured in the HyperConverged custom resource.
  • The VM is stopped.

Procedure

  • Assign the mediated device to a virtual machine (VM) by editing the spec.domain.devices.gpus stanza of the VirtualMachine manifest:

    Example virtual machine manifest

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    spec:
      domain:
        devices:
          gpus:
          - deviceName: nvidia.com/TU104GL_Tesla_T4 1
            name: gpu1 2
          - deviceName: nvidia.com/GRID_T4-2Q
            name: gpu2

    1
    The resource name associated with the mediated device.
    2
    A name to identify the device on the VM.

Verification

  • To verify that the device is available from the virtual machine, run the following command, substituting <device_name> with the deviceName value from the VirtualMachine manifest:

    $ lspci -nnk | grep <device_name>
7.14.13.6.2. Assigning a vGPU to a VM by using the web console

You can assign virtual GPUs to virtual machines by using the OpenShift Container Platform web console.

Note

You can add hardware devices to virtual machines created from customized templates or a YAML file. You cannot add devices to pre-supplied boot source templates for specific operating systems.

Prerequisites

  • The vGPU is configured as a mediated device in your cluster.

    • To view the devices that are connected to your cluster, click ComputeHardware Devices from the side menu.
  • The VM is stopped.

Procedure

  1. In the OpenShift Container Platform web console, click VirtualizationVirtualMachines from the side menu.
  2. Select the VM that you want to assign the device to.
  3. On the Details tab, click GPU devices.
  4. Click Add GPU device.
  5. Enter an identifying value in the Name field.
  6. From the Device name list, select the device that you want to add to the VM.
  7. Click Save.

Verification

  • To confirm that the devices were added to the VM, click the YAML tab and review the VirtualMachine configuration. Mediated devices are added to the spec.domain.devices stanza.
7.14.13.7. Additional resources

7.14.14. Configuring USB host passthrough

As a cluster administrator, you can expose USB devices in a cluster, making them available for virtual machine (VM) owners to assign to VMs. Enabling this passthrough of USB devices allows a guest to connect to actual USB hardware that is attached to an OpenShift Container Platform node, as if the hardware and the VM are physically connected.

You can expose a USB device by first enabling host passthrough and then configuring the VM to use the USB device.

7.14.14.1. Enabling USB host passthrough

You can enable USB host passthrough at the cluster level.

You specify a resource name and USB device name for each device you want first to add and then assign to a virtual machine (VM). You can allocate more than one device, each of which is known as a selector in the HyperConverged (HCO) custom resource (CR), to a single resource name. If you have multiple, identical USB devices on the cluster, you can choose to allocate a VM to a specific device.

Prerequisites

  • You have access to an OpenShift Container Platform cluster as a user who has the cluster-admin role.

Procedure

  1. Identify the USB device vendor and product by running the following command:

    $ lsusb
  2. Open the HCO CR by running the following commmand:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  3. Add a USB device to the permittedHostDevices stanza, as shown in the following example:

    Example YAML snippet

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
       name: kubevirt-hyperconverged
       namespace: {CNVNamespace}
    spec:
      configuration:
        permittedHostDevices: 1
          usbHostDevices: 2
            - resourceName: kubevirt.io/peripherals 3
              selectors:
                - vendor: "045e"
                  product: "07a5"
                - vendor: "062a"
                  product: "4102"
                - vendor: "072f"
                  product: "b100"

    1
    Lists the host devices that have permission to be used in the cluster.
    2
    Lists the available USB devices.
    3
    Uses resourceName: deviceName for each device you want to add and assign to the VM. In this example, the resource is bound to three devices, each of which is identified by vendor and product and is known as a selector.
7.14.14.2. Configuring a virtual machine connection to a USB device

You can configure virtual machine (VM) access to a USB device. This configuration allows a guest to connect to actual USB hardware that is attached to an OpenShift Container Platform node, as if the hardware and the VM are physically connected.

Procedure

  1. Locate the USB device by running the following command:

    $ oc /dev/serial/by-id/usb-VENDOR_device_name
  2. Open the virtual machine instance custom resource (CR) by running the following commmand:

    $ oc edit vmi vmi-usb
  3. Edit the CR by adding a USB device, as shown in the following example:

    Example configuration

    apiVersion: kubevirt.io/v1
    kind: VirtualMachineInstance
    metadata:
      labels:
        special: vmi-usb
      name: vmi-usb 1
    spec:
      domain:
        devices:
          hostDevices:
          - deviceName: kubevirt.io/peripherals
            name: local-peripherals
    # ...

    1
    The name of the USB device.

7.14.15. Enabling descheduler evictions on virtual machines

You can use the descheduler to evict pods so that the pods can be rescheduled onto more appropriate nodes. If the pod is a virtual machine, the pod eviction causes the virtual machine to be live migrated to another node.

7.14.15.1. Descheduler profiles

Use the LongLifecycle profile to enable the descheduler on a virtual machine. This is the only descheduler profile currently available for OpenShift Virtualization. To ensure proper scheduling, create VMs with CPU and memory requests for the expected load.

LongLifecycle

This profile balances resource usage between nodes and enables the following strategies:

  • RemovePodsHavingTooManyRestarts: removes pods whose containers have been restarted too many times and pods where the sum of restarts over all containers (including Init Containers) is more than 100. Restarting the VM guest operating system does not increase this count.
  • LowNodeUtilization: evicts pods from overutilized nodes when there are any underutilized nodes. The destination node for the evicted pod will be determined by the scheduler.

    • A node is considered underutilized if its usage is below 20% for all thresholds (CPU, memory, and number of pods).
    • A node is considered overutilized if its usage is above 50% for any of the thresholds (CPU, memory, and number of pods).
7.14.15.2. Installing the descheduler

The descheduler is not available by default. To enable the descheduler, you must install the Kube Descheduler Operator from OperatorHub and enable one or more descheduler profiles.

By default, the descheduler runs in predictive mode, which means that it only simulates pod evictions. You must change the mode to automatic for the descheduler to perform the pod evictions.

Important

If you have enabled hosted control planes in your cluster, set a custom priority threshold to lower the chance that pods in the hosted control plane namespaces are evicted. Set the priority threshold class name to hypershift-control-plane, because it has the lowest priority value (100000000) of the hosted control plane priority classes.

Prerequisites

  • You are logged in to OpenShift Container Platform as a user with the cluster-admin role.
  • Access to the OpenShift Container Platform web console.

Procedure

  1. Log in to the OpenShift Container Platform web console.
  2. Create the required namespace for the Kube Descheduler Operator.

    1. Navigate to AdministrationNamespaces and click Create Namespace.
    2. Enter openshift-kube-descheduler-operator in the Name field, enter openshift.io/cluster-monitoring=true in the Labels field to enable descheduler metrics, and click Create.
  3. Install the Kube Descheduler Operator.

    1. Navigate to OperatorsOperatorHub.
    2. Type Kube Descheduler Operator into the filter box.
    3. Select the Kube Descheduler Operator and click Install.
    4. On the Install Operator page, select A specific namespace on the cluster. Select openshift-kube-descheduler-operator from the drop-down menu.
    5. Adjust the values for the Update Channel and Approval Strategy to the desired values.
    6. Click Install.
  4. Create a descheduler instance.

    1. From the OperatorsInstalled Operators page, click the Kube Descheduler Operator.
    2. Select the Kube Descheduler tab and click Create KubeDescheduler.
    3. Edit the settings as necessary.

      1. To evict pods instead of simulating the evictions, change the Mode field to Automatic.
      2. Expand the Profiles section and select LongLifecycle. The AffinityAndTaints profile is enabled by default.

        Important

        The only profile currently available for OpenShift Virtualization is LongLifecycle.

You can also configure the profiles and settings for the descheduler later using the OpenShift CLI (oc).

7.14.15.3. Enabling descheduler evictions on a virtual machine (VM)

After the descheduler is installed, you can enable descheduler evictions on your VM by adding an annotation to the VirtualMachine custom resource (CR).

Prerequisites

  • Install the descheduler in the OpenShift Container Platform web console or OpenShift CLI (oc).
  • Ensure that the VM is not running.

Procedure

  1. Before starting the VM, add the descheduler.alpha.kubernetes.io/evict annotation to the VirtualMachine CR:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    spec:
      template:
        metadata:
          annotations:
            descheduler.alpha.kubernetes.io/evict: "true"
  2. Configure the KubeDescheduler object with the LongLifecycle profile and enable background evictions for improved VM eviction stability during live migration:

    apiVersion: operator.openshift.io/v1
    kind: KubeDescheduler
    metadata:
      name: cluster
      namespace: openshift-kube-descheduler-operator
    spec:
      deschedulingIntervalSeconds: 3600
      profiles:
      - LongLifecycle 1
      mode: Predictive 2
      profileCustomizations:
        devEnableEvictionsInBackground: true 3
    1
    You can only set the LongLifecycle profile. This profile balances resource usage between nodes.
    2
    By default, the descheduler does not evict pods. To evict pods, set mode to Automatic.
    3
    Enabling devEnableEvictionsInBackground allows evictions to occur in the background, improving stability and mitigating oscillatory behavior during live migrations.

The descheduler is now enabled on the VM.

7.14.15.4. Additional resources

7.14.16. About high availability for virtual machines

You can enable high availability for virtual machines (VMs) by manually deleting a failed node to trigger VM failover or by configuring remediating nodes.

Manually deleting a failed node

If a node fails and machine health checks are not deployed on your cluster, virtual machines with runStrategy: Always configured are not automatically relocated to healthy nodes. To trigger VM failover, you must manually delete the Node object.

See Deleting a failed node to trigger virtual machine failover.

Configuring remediating nodes

You can configure remediating nodes by installing the Self Node Remediation Operator or the Fence Agents Remediation Operator from the OperatorHub and enabling machine health checks or node remediation checks.

For more information on remediation, fencing, and maintaining nodes, see the Workload Availability for Red Hat OpenShift documentation.

7.14.17. Virtual machine control plane tuning

OpenShift Virtualization offers the following tuning options at the control-plane level:

  • The highBurst profile, which uses fixed QPS and burst rates, to create hundreds of virtual machines (VMs) in one batch
  • Migration setting adjustment based on workload type
7.14.17.1. Configuring a highBurst profile

Use the highBurst profile to create and maintain a large number of virtual machines (VMs) in one cluster.

Procedure

  • Apply the following patch to enable the highBurst tuning policy profile:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
      --type=json -p='[{"op": "add", "path": "/spec/tuningPolicy", \
      "value": "highBurst"}]'

Verification

  • Run the following command to verify the highBurst tuning policy profile is enabled:

    $ oc get kubevirt.kubevirt.io/kubevirt-kubevirt-hyperconverged \
      -n openshift-cnv -o go-template --template='{{range $config, \
      $value := .spec.configuration}} {{if eq $config "apiConfiguration" \
      "webhookConfiguration" "controllerConfiguration" "handlerConfiguration"}} \
      {{"\n"}} {{$config}} = {{$value}} {{end}} {{end}} {{"\n"}}

7.14.18. Assigning compute resources

In OpenShift Virtualization, compute resources assigned to virtual machines (VMs) are backed by either guaranteed CPUs or time-sliced CPU shares.

Guaranteed CPUs, also known as CPU reservation, dedicate CPU cores or threads to a specific workload, which makes them unavailable to any other workload. Assigning guaranteed CPUs to a VM ensures that the VM will have sole access to a reserved physical CPU. Enable dedicated resources for VMs to use a guaranteed CPU.

Time-sliced CPUs dedicate a slice of time on a shared physical CPU to each workload. You can specify the size of the slice during VM creation, or when the VM is offline. By default, each vCPU receives 100 milliseconds, or 1/10 of a second, of physical CPU time.

The type of CPU reservation depends on the instance type or VM configuration.

7.14.18.1. Overcommitting CPU resources

Time-slicing allows multiple virtual CPUs (vCPUs) to share a single physical CPU. This is known as CPU overcommitment. Guaranteed VMs can not be overcommitted.

Configure CPU overcommitment to prioritize VM density over performance when assigning CPUs to VMs. With a higher CPU over-commitment of vCPUs, more VMs fit onto a given node.

7.14.18.2. Setting the CPU allocation ratio

The CPU Allocation Ratio specifies the degree of overcommitment by mapping vCPUs to time slices of physical CPUs.

For example, a mapping or ratio of 10:1 maps 10 virtual CPUs to 1 physical CPU by using time slices.

To change the default number of vCPUs mapped to each physical CPU, set the vmiCPUAllocationRatio value in the HyperConverged CR. The pod CPU request is calculated by multiplying the number of vCPUs by the reciprocal of the CPU allocation ratio. For example, if vmiCPUAllocationRatio is set to 10, OpenShift Virtualization will request 10 times fewer CPUs on the pod for that VM.

Procedure

Set the vmiCPUAllocationRatio value in the HyperConverged CR to define a node CPU allocation ratio.

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Set the vmiCPUAllocationRatio:

    ...
    spec:
      resourceRequirements:
        vmiCPUAllocationRatio: 1 1
    # ...
    1
    When vmiCPUAllocationRatio is set to 1, the maximum amount of vCPUs are requested for the pod.
7.14.18.3. Additional resources

7.14.19. About multi-queue functionality

Use multi-queue functionality to scale network throughput and performance on virtual machines (VMs) with multiple vCPUs.

By default, the queueCount value, which is derived from the domain XML, is determined by the number of vCPUs allocated to a VM. Network performance does not scale as the number of vCPUs increases. Additionally, because virtio-net has only one Tx and Rx queue, guests cannot transmit or retrieve packs in parallel.

Note

Enabling virtio-net multiqueue does not offer significant improvements when the number of vNICs in a guest instance is proportional to the number of vCPUs.

7.14.19.1. Known limitations
  • MSI vectors are still consumed if virtio-net multiqueue is enabled in the host but not enabled in the guest operating system by the administrator.
  • Each virtio-net queue consumes 64 KiB of kernel memory for the vhost driver.
  • Starting a VM with more than 16 CPUs results in no connectivity if networkInterfaceMultiqueue is set to 'true' (CNV-16107).
7.14.19.2. Enabling multi-queue functionality

Enable multi-queue functionality for interfaces configured with a VirtIO model.

Procedure

  1. Set the networkInterfaceMultiqueue value to true in the VirtualMachine manifest file of your VM to enable multi-queue functionality:

    apiVersion: kubevirt.io/v1
    kind: VM
    spec:
      domain:
        devices:
          networkInterfaceMultiqueue: true
  2. Save the VirtualMachine manifest file to apply your changes.

7.15. VM disks

7.15.1. Hot-plugging VM disks

You can add or remove virtual disks without stopping your virtual machine (VM) or virtual machine instance (VMI).

Only data volumes and persistent volume claims (PVCs) can be hot plugged and hot-unplugged. You cannot hot plug or hot-unplug container disks.

A hot plugged disk remains attached to the VM even after reboot. You must detach the disk to remove it from the VM.

You can make a hot plugged disk persistent so that it is permanently mounted on the VM.

Note

Each VM has a virtio-scsi controller so that hot plugged disks can use the scsi bus. The virtio-scsi controller overcomes the limitations of virtio while retaining its performance advantages. It is highly scalable and supports hot plugging over 4 million disks.

Regular virtio is not available for hot plugged disks because it is not scalable. Each virtio disk uses one of the limited PCI Express (PCIe) slots in the VM. PCIe slots are also used by other devices and must be reserved in advance. Therefore, slots might not be available on demand.

7.15.1.1. Hot plugging and hot unplugging a disk by using the web console

You can hot plug a disk by attaching it to a virtual machine (VM) while the VM is running by using the OpenShift Container Platform web console.

The hot plugged disk remains attached to the VM until you unplug it.

You can make a hot plugged disk persistent so that it is permanently mounted on the VM.

Prerequisites

  • You must have a data volume or persistent volume claim (PVC) available for hot plugging.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a running VM to view its details.
  3. On the VirtualMachine details page, click ConfigurationDisks.
  4. Add a hot plugged disk:

    1. Click Add disk.
    2. In the Add disk (hot plugged) window, select the disk from the Source list and click Save.
  5. Optional: Unplug a hot plugged disk:

    1. Click the options menu kebab beside the disk and select Detach.
    2. Click Detach.
  6. Optional: Make a hot plugged disk persistent:

    1. Click the options menu kebab beside the disk and select Make persistent.
    2. Reboot the VM to apply the change.
7.15.1.2. Hot plugging and hot unplugging a disk by using the command line

You can hot plug and hot unplug a disk while a virtual machine (VM) is running by using the command line.

You can make a hot plugged disk persistent so that it is permanently mounted on the VM.

Prerequisites

  • You must have at least one data volume or persistent volume claim (PVC) available for hot plugging.

Procedure

  • Hot plug a disk by running the following command:

    $ virtctl addvolume <virtual-machine|virtual-machine-instance> \
      --volume-name=<datavolume|PVC> \
      [--persist] [--serial=<label-name>]
    • Use the optional --persist flag to add the hot plugged disk to the virtual machine specification as a permanently mounted virtual disk. Stop, restart, or reboot the virtual machine to permanently mount the virtual disk. After specifying the --persist flag, you can no longer hot plug or hot unplug the virtual disk. The --persist flag applies to virtual machines, not virtual machine instances.
    • The optional --serial flag allows you to add an alphanumeric string label of your choice. This helps you to identify the hot plugged disk in a guest virtual machine. If you do not specify this option, the label defaults to the name of the hot plugged data volume or PVC.
  • Hot unplug a disk by running the following command:

    $ virtctl removevolume <virtual-machine|virtual-machine-instance> \
      --volume-name=<datavolume|PVC>

7.15.2. Expanding virtual machine disks

You can increase the size of a virtual machine (VM) disk by expanding the persistent volume claim (PVC) of the disk.

If your storage provider does not support volume expansion, you can expand the available virtual storage of a VM by adding blank data volumes.

You cannot reduce the size of a VM disk.

7.15.2.1. Expanding a VM disk PVC

You can increase the size of a virtual machine (VM) disk by expanding the persistent volume claim (PVC) of the disk.

If the PVC uses the file system volume mode, the disk image file expands to the available size while reserving some space for file system overhead.

Procedure

  1. Edit the PersistentVolumeClaim manifest of the VM disk that you want to expand:

    $ oc edit pvc <pvc_name>
  2. Update the disk size:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
       name: vm-disk-expand
    spec:
      accessModes:
         - ReadWriteMany
      resources:
        requests:
           storage: 3Gi 1
    # ...
    1
    Specify the new disk size.
7.15.2.2. Expanding available virtual storage by adding blank data volumes

You can expand the available storage of a virtual machine (VM) by adding blank data volumes.

Prerequisites

  • You must have at least one persistent volume.

Procedure

  1. Create a DataVolume manifest as shown in the following example:

    Example DataVolume manifest

    apiVersion: cdi.kubevirt.io/v1beta1
    kind: DataVolume
    metadata:
      name: blank-image-datavolume
    spec:
      source:
        blank: {}
      storage:
        resources:
          requests:
            storage: <2Gi> 1
      storageClassName: "<storage_class>" 2

    1
    Specify the amount of available space requested for the data volume.
    2
    Optional: If you do not specify a storage class, the default storage class is used.
  2. Create the data volume by running the following command:

    $ oc create -f <blank-image-datavolume>.yaml

7.15.3. Configuring shared volumes for virtual machines

You can configure shared disks to allow multiple virtual machines (VMs) to share the same underlying storage. A shared disk’s volume must be block mode.

You configure disk sharing by exposing the storage as either of these types:

  • An ordinary VM disk
  • A logical unit number (LUN) disk with an SCSI connection and raw device mapping, as required for Windows Failover Clustering for shared volumes

In addition to configuring disk sharing, you can also set an error policy for each ordinary VM disk or LUN disk. The error policy controls how the hypervisor behaves when an input/output error occurs on a disk Read or Write.

7.15.3.1. Configuring disk sharing by using virtual machine disks

You can configure block volumes so that multiple virtual machines (VMs) can share storage.

The application running on the guest operating system determines the storage option you must configure for the VM. A disk of type disk exposes the volume as an ordinary disk to the VM.

You can set an error policy for each disk. The error policy controls how the hypervisor behaves when an input/output error occurs while a disk is being written to or read. The default behavior stops the VM and generates a Kubernetes event.

You can accept the default behavior, or you can set the error policy to one of the following options:

  • report, which reports the error in the guest.
  • ignore, which ignores the error. The Read or Write failure is undetected.
  • enospace, which produces an error indicating that there is not enough disk space.

Prerequisites

  • The volume access mode must be ReadWriteMany (RWX) if the VMs that are sharing disks are running on different nodes.

    If the VMs that are sharing disks are running on the same node, ReadWriteOnce (RWO) volume access mode is sufficient.

  • The storage provider must support the required Container Storage Interface (CSI) driver.

Procedure

  1. Create the VirtualMachine manifest for your VM to set the required values, as shown in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: <vm_name>
    spec:
      template:
    # ...
        spec:
          domain:
            devices:
              disks:
              - disk:
                  bus: virtio
                name: rootdisk
                errorPolicy: report 1
                disk1: disk_one 2
              - disk:
                  bus: virtio
                name: cloudinitdisk
                disk2: disk_two
                shareable: true 3
              interfaces:
              - masquerade: {}
                name: default
    1
    Identifies the error policy.
    2
    Identifies a device as a disk.
    3
    Identifies a shared disk.
  2. Save the VirtualMachine manifest file to apply your changes.
7.15.3.2. Configuring disk sharing by using LUN

To secure data on your VM from outside access, you can enable SCSI persistent reservation and configure a LUN-backed virtual machine disk to be shared among multiple virtual machines. By enabling the shared option, you can use advanced SCSI commands, such as those required for a Windows failover clustering implementation, for managing the underlying storage.

When a storage volume is configured as the LUN disk type, a VM can use the volume as a logical unit number (LUN) device. As a result, the VM can deploy and manage the disk by using SCSI commands.

You reserve a LUN through the SCSI persistent reserve options. To enable the reservation:

  1. Configure the feature gate option
  2. Activate the feature gate option on the LUN disk to issue SCSI device-specific input and output controls (IOCTLs) that the VM requires.

You can set an error policy for each LUN disk. The error policy controls how the hypervisor behaves when an input/output error occurs on a disk Read or Write. The default behavior stops the guest and generates a Kubernetes event.

For a LUN disk with an SCSi connection and a persistent reservation, as required for Windows Failover Clustering for shared volumes, you set the error policy to report.

Prerequisites

  • You must have cluster administrator privileges to configure the feature gate option.
  • The volume access mode must be ReadWriteMany (RWX) if the VMs that are sharing disks are running on different nodes.

    If the VMs that are sharing disks are running on the same node, ReadWriteOnce (RWO) volume access mode is sufficient.

  • The storage provider must support a Container Storage Interface (CSI) driver that uses Fibre Channel (FC), Fibre Channel over Ethernet (FCoE), or iSCSI storage protocols.
  • If you are a cluster administrator and intend to configure disk sharing by using LUN, you must enable the cluster’s feature gate on the HyperConverged custom resource (CR).
  • Disks that you want to share must be in block mode.

Procedure

  1. Edit or create the VirtualMachine manifest for your VM to set the required values, as shown in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-0
    spec:
      template:
        spec:
          domain:
            devices:
              disks:
              - disk:
                  bus: sata
                name: rootdisk
              - errorPolicy: report 1
                lun: 2
                  bus: scsi
                  reservation: true 3
                name: na-shared
                serial: shared1234
          volumes:
          - dataVolume:
              name: vm-0
            name: rootdisk
          - name: na-shared
            persistentVolumeClaim:
              claimName: pvc-na-share
    1
    Identifies the error policy.
    2
    Identifies a LUN disk.
    3
    Identifies that the persistent reservation is enabled.
  2. Save the VirtualMachine manifest file to apply your changes.
7.15.3.2.1. Configuring disk sharing by using LUN and the web console

You can use the OpenShift Container Platform web console to configure disk sharing by using LUN.

Prerequisites

  • The cluster administrator must enable the persistentreservation feature gate setting.

Procedure

  1. Click VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. Expand Storage.
  4. On the Disks tab, click Add disk.
  5. Specify the Name, Source, Size, Interface, and Storage Class.
  6. Select LUN as the Type.
  7. Select Shared access (RWX) as the Access Mode.
  8. Select Block as the Volume Mode.
  9. Expand Advanced Settings, and select both checkboxes.
  10. Click Save.
7.15.3.2.2. Configuring disk sharing by using LUN and the command line

You can use the command line to configure disk sharing by using LUN.

Procedure

  1. Edit or create the VirtualMachine manifest for your VM to set the required values, as shown in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-0
    spec:
      template:
        spec:
          domain:
            devices:
              disks:
              - disk:
                  bus: sata
                name: rootdisk
              - errorPolicy: report
                lun: 1
                  bus: scsi
                  reservation: true 2
                name: na-shared
                serial: shared1234
          volumes:
          - dataVolume:
              name: vm-0
            name: rootdisk
          - name: na-shared
            persistentVolumeClaim:
              claimName: pvc-na-share
    1
    Identifies a LUN disk.
    2
    Identifies that the persistent reservation is enabled.
  2. Save the VirtualMachine manifest file to apply your changes.
7.15.3.3. Enabling the PersistentReservation feature gate

You can enable the SCSI persistentReservation feature gate and allow a LUN-backed block mode virtual machine (VM) disk to be shared among multiple virtual machines.

The persistentReservation feature gate is disabled by default. You can enable the persistentReservation feature gate by using the web console or the command line.

Prerequisites

  • Cluster administrator privileges are required.
  • The volume access mode ReadWriteMany (RWX) is required if the VMs that are sharing disks are running on different nodes. If the VMs that are sharing disks are running on the same node, the ReadWriteOnce (RWO) volume access mode is sufficient.
  • The storage provider must support a Container Storage Interface (CSI) driver that uses Fibre Channel (FC), Fibre Channel over Ethernet (FCoE), or iSCSI storage protocols.
7.15.3.3.1. Enabling the PersistentReservation feature gate by using the web console

You must enable the PersistentReservation feature gate to allow a LUN-backed block mode virtual machine (VM) disk to be shared among multiple virtual machines. Enabling the feature gate requires cluster administrator privileges.

Procedure

  1. Click VirtualizationOverview in the web console.
  2. Click the Settings tab.
  3. Select Cluster.
  4. Expand SCSI persistent reservation and set Enable persistent reservation to on.
7.15.3.3.2. Enabling the PersistentReservation feature gate by using the command line

You enable the persistentReservation feature gate by using the command line. Enabling the feature gate requires cluster administrator privileges.

Procedure

  1. Enable the persistentReservation feature gate by running the following command:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv --type json -p \
    '[{"op":"replace","path":"/spec/featureGates/persistentReservation", "value": true}]'

Chapter 8. Networking

8.1. Networking overview

OpenShift Virtualization provides advanced networking functionality by using custom resources and plugins. Virtual machines (VMs) are integrated with OpenShift Container Platform networking and its ecosystem.

Note

You cannot run OpenShift Virtualization on a single-stack IPv6 cluster.

The following figure illustrates the typical network setup of OpenShift Virtualization. Other configurations are also possible.

Figure 8.1. OpenShift Virtualization networking overview

OpenShift Virtualization networking architecture

20 Pods and VMs run on the same network infrastructure which allows you to easily connect your containerized and virtualized workloads.

20 You can connect VMs to the default pod network and to any number of secondary networks.

20 The default pod network provides connectivity between all its members, service abstraction, IP management, micro segmentation, and other functionality.

20 Multus is a "meta" CNI plugin that enables a pod or virtual machine to connect to additional network interfaces by using other compatible CNI plugins.

20 The default pod network is overlay-based, tunneled through the underlying machine network.

20 The machine network can be defined over a selected set of network interface controllers (NICs).

20 Secondary VM networks are typically bridged directly to a physical network, with or without VLAN encapsulation. It is also possible to create virtual overlay networks for secondary networks.

Note

Connecting VMs directly to the underlay network is not supported on Red Hat OpenShift Service on AWS.

20 Secondary VM networks can be defined on dedicated set of NICs, as shown in Figure 1, or they can use the machine network.

8.1.1. OpenShift Virtualization networking glossary

The following terms are used throughout OpenShift Virtualization documentation:

Container Network Interface (CNI)
A Cloud Native Computing Foundation project, focused on container network connectivity. OpenShift Virtualization uses CNI plugins to build upon the basic Kubernetes networking functionality.
Multus
A "meta" CNI plugin that allows multiple CNIs to exist so that a pod or virtual machine can use the interfaces it needs.
Custom resource definition (CRD)
A Kubernetes API resource that allows you to define custom resources, or an object defined by using the CRD API resource.
Network attachment definition (NAD)
A CRD introduced by the Multus project that allows you to attach pods, virtual machines, and virtual machine instances to one or more networks.
Node network configuration policy (NNCP)
A CRD introduced by the nmstate project, describing the requested network configuration on nodes. You update the node network configuration, including adding and removing interfaces, by applying a NodeNetworkConfigurationPolicy manifest to the cluster.

8.1.2. Using the default pod network

Connecting a virtual machine to the default pod network
Each VM is connected by default to the default internal pod network. You can add or remove network interfaces by editing the VM specification.
Exposing a virtual machine as a service
You can expose a VM within the cluster or outside the cluster by creating a Service object. For on-premise clusters, you can configure a load balancing service by using the MetalLB Operator. You can install the MetalLB Operator by using the OpenShift Container Platform web console or the CLI.

8.1.3. Configuring VM secondary network interfaces

You can connect a virtual machine to a secondary network by using Linux bridge, SR-IOV and OVN-Kubernetes CNI plugins. You can list multiple secondary networks and interfaces in the VM specification. It is not required to specify the primary pod network in the VM specification when connecting to a secondary network interface.

Connecting a virtual machine to an OVN-Kubernetes secondary network

You can connect a VM to an OVN-Kubernetes secondary network. OpenShift Virtualization supports the layer2 and localnet topologies for OVN-Kubernetes. The localnet topology is the recommended way of exposing VMs to the underlying physical network, with or without VLAN encapsulation.

  • A layer2 topology connects workloads by a cluster-wide logical switch. The OVN-Kubernetes CNI plugin uses the Geneve (Generic Network Virtualization Encapsulation) protocol to create an overlay network between nodes. You can use this overlay network to connect VMs on different nodes, without having to configure any additional physical networking infrastructure.
  • A localnet topology connects the secondary network to the physical underlay. This enables both east-west cluster traffic and access to services running outside the cluster, but it requires additional configuration of the underlying Open vSwitch (OVS) system on cluster nodes.

To configure an OVN-Kubernetes secondary network and attach a VM to that network, perform the following steps:

  1. Configure an OVN-Kubernetes secondary network by creating a network attachment definition (NAD).

    Note

    For localnet topology, you must configure an OVS bridge by creating a NodeNetworkConfigurationPolicy object before creating the NAD.

  2. Connect the VM to the OVN-Kubernetes secondary network by adding the network details to the VM specification.
Connecting a virtual machine to an SR-IOV network

You can use Single Root I/O Virtualization (SR-IOV) network devices with additional networks on your OpenShift Container Platform cluster installed on bare metal or Red Hat OpenStack Platform (RHOSP) infrastructure for applications that require high bandwidth or low latency.

You must install the SR-IOV Network Operator on your cluster to manage SR-IOV network devices and network attachments.

You can connect a VM to an SR-IOV network by performing the following steps:

  1. Configure an SR-IOV network device by creating a SriovNetworkNodePolicy CRD.
  2. Configure an SR-IOV network by creating an SriovNetwork object.
  3. Connect the VM to the SR-IOV network by including the network details in the VM configuration.
Connecting a virtual machine to a Linux bridge network

Install the Kubernetes NMState Operator to configure Linux bridges, VLANs, and bonding for your secondary networks. The OVN-Kubernetes localnet topology is the recommended way of connecting a VM to the underlying physical network, but OpenShift Virtualization also supports Linux bridge networks.

Note

You cannot directly attach to the default machine network when using Linux bridge networks.

You can create a Linux bridge network and attach a VM to the network by performing the following steps:

  1. Configure a Linux bridge network device by creating a NodeNetworkConfigurationPolicy custom resource definition (CRD).
  2. Configure a Linux bridge network by creating a NetworkAttachmentDefinition CRD.
  3. Connect the VM to the Linux bridge network by including the network details in the VM configuration.
Hot plugging secondary network interfaces
You can add or remove secondary network interfaces without stopping your VM. OpenShift Virtualization supports hot plugging and hot unplugging for secondary interfaces that use bridge binding and the VirtIO device driver. OpenShift Virtualization also supports hot plugging secondary interfaces that use the SR-IOV binding.
Using DPDK with SR-IOV
The Data Plane Development Kit (DPDK) provides a set of libraries and drivers for fast packet processing. You can configure clusters and VMs to run DPDK workloads over SR-IOV networks.
Configuring a dedicated network for live migration
You can configure a dedicated Multus network for live migration. A dedicated network minimizes the effects of network saturation on tenant workloads during live migration.
Accessing a virtual machine by using the cluster FQDN
You can access a VM that is attached to a secondary network interface from outside the cluster by using its fully qualified domain name (FQDN).
Configuring and viewing IP addresses
You can configure an IP address of a secondary network interface when you create a VM. The IP address is provisioned with cloud-init. You can view the IP address of a VM by using the OpenShift Container Platform web console or the command line. The network information is collected by the QEMU guest agent.
8.1.3.1. Comparing Linux bridge CNI and OVN-Kubernetes localnet topology

The following table provides a comparison of features available when using the Linux bridge CNI compared to the localnet topology for an OVN-Kubernetes plugin:

Table 8.1. Linux bridge CNI compared to an OVN-Kubernetes localnet topology
FeatureAvailable on Linux bridge CNIAvailable on OVN-Kubernetes localnet

Layer 2 access to the underlay native network

Only on secondary network interface controllers (NICs)

Yes

Layer 2 access to underlay VLANs

Yes

Yes

Network policies

No

Yes

Managed IP pools

No

Yes

MAC spoof filtering

Yes

Yes

8.1.4. Integrating with OpenShift Service Mesh

Connecting a virtual machine to a service mesh
OpenShift Virtualization is integrated with OpenShift Service Mesh. You can monitor, visualize, and control traffic between pods and virtual machines.

8.1.5. Managing MAC address pools

Managing MAC address pools for network interfaces
The KubeMacPool component allocates MAC addresses for VM network interfaces from a shared MAC address pool. This ensures that each network interface is assigned a unique MAC address. A virtual machine instance created from that VM retains the assigned MAC address across reboots.

8.1.6. Configuring SSH access

Configuring SSH access to virtual machines

You can configure SSH access to VMs by using the following methods:

  • virtctl ssh command

    You create an SSH key pair, add the public key to a VM, and connect to the VM by running the virtctl ssh command with the private key.

    You can add public SSH keys to Red Hat Enterprise Linux (RHEL) 9 VMs at runtime or at first boot to VMs with guest operating systems that can be configured by using a cloud-init data source.

  • virtctl port-forward command

    You add the virtctl port-foward command to your .ssh/config file and connect to the VM by using OpenSSH.

  • Service

    You create a service, associate the service with the VM, and connect to the IP address and port exposed by the service.

  • Secondary network

    You configure a secondary network, attach a VM to the secondary network interface, and connect to its allocated IP address.

8.2. Connecting a virtual machine to the default pod network

You can connect a virtual machine to the default internal pod network by configuring its network interface to use the masquerade binding mode.

Note

Traffic passing through network interfaces to the default pod network is interrupted during live migration.

8.2.1. Configuring masquerade mode from the command line

You can use masquerade mode to hide a virtual machine’s outgoing traffic behind the pod IP address. Masquerade mode uses Network Address Translation (NAT) to connect virtual machines to the pod network backend through a Linux bridge.

Enable masquerade mode and allow traffic to enter the virtual machine by editing your virtual machine configuration file.

Prerequisites

  • The virtual machine must be configured to use DHCP to acquire IPv4 addresses.

Procedure

  1. Edit the interfaces spec of your virtual machine configuration file:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
    spec:
      template:
        spec:
          domain:
            devices:
              interfaces:
                - name: default
                  masquerade: {} 1
                  ports: 2
                    - port: 80
    # ...
          networks:
          - name: default
            pod: {}
    1
    Connect using masquerade mode.
    2
    Optional: List the ports that you want to expose from the virtual machine, each specified by the port field. The port value must be a number between 0 and 65536. When the ports array is not used, all ports in the valid range are open to incoming traffic. In this example, incoming traffic is allowed on port 80.
    Note

    Ports 49152 and 49153 are reserved for use by the libvirt platform and all other incoming traffic to these ports is dropped.

  2. Create the virtual machine:

    $ oc create -f <vm-name>.yaml

8.2.2. Configuring masquerade mode with dual-stack (IPv4 and IPv6)

You can configure a new virtual machine (VM) to use both IPv6 and IPv4 on the default pod network by using cloud-init.

The Network.pod.vmIPv6NetworkCIDR field in the virtual machine instance configuration determines the static IPv6 address of the VM and the gateway IP address. These are used by the virt-launcher pod to route IPv6 traffic to the virtual machine and are not used externally. The Network.pod.vmIPv6NetworkCIDR field specifies an IPv6 address block in Classless Inter-Domain Routing (CIDR) notation. The default value is fd10:0:2::2/120. You can edit this value based on your network requirements.

When the virtual machine is running, incoming and outgoing traffic for the virtual machine is routed to both the IPv4 address and the unique IPv6 address of the virt-launcher pod. The virt-launcher pod then routes the IPv4 traffic to the DHCP address of the virtual machine, and the IPv6 traffic to the statically set IPv6 address of the virtual machine.

Prerequisites

  • The OpenShift Container Platform cluster must use the OVN-Kubernetes Container Network Interface (CNI) network plugin configured for dual-stack.

Procedure

  1. In a new virtual machine configuration, include an interface with masquerade and configure the IPv6 address and default gateway by using cloud-init.

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm-ipv6
    spec:
      template:
        spec:
          domain:
            devices:
              interfaces:
                - name: default
                  masquerade: {} 1
                  ports:
                    - port: 80 2
    # ...
          networks:
          - name: default
            pod: {}
          volumes:
          - cloudInitNoCloud:
              networkData: |
                version: 2
                ethernets:
                  eth0:
                    dhcp4: true
                    addresses: [ fd10:0:2::2/120 ] 3
                    gateway6: fd10:0:2::1 4
    1
    Connect using masquerade mode.
    2
    Allows incoming traffic on port 80 to the virtual machine.
    3
    The static IPv6 address as determined by the Network.pod.vmIPv6NetworkCIDR field in the virtual machine instance configuration. The default value is fd10:0:2::2/120.
    4
    The gateway IP address as determined by the Network.pod.vmIPv6NetworkCIDR field in the virtual machine instance configuration. The default value is fd10:0:2::1.
  2. Create the virtual machine in the namespace:

    $ oc create -f example-vm-ipv6.yaml

Verification

  • To verify that IPv6 has been configured, start the virtual machine and view the interface status of the virtual machine instance to ensure it has an IPv6 address:
$ oc get vmi <vmi-name> -o jsonpath="{.status.interfaces[*].ipAddresses}"

8.2.3. About jumbo frames support

When using the OVN-Kubernetes CNI plugin, you can send unfragmented jumbo frame packets between two virtual machines (VMs) that are connected on the default pod network. Jumbo frames have a maximum transmission unit (MTU) value greater than 1500 bytes.

The VM automatically gets the MTU value of the cluster network, set by the cluster administrator, in one of the following ways:

  • libvirt: If the guest OS has the latest version of the VirtIO driver that can interpret incoming data via a Peripheral Component Interconnect (PCI) config register in the emulated device.
  • DHCP: If the guest DHCP client can read the MTU value from the DHCP server response.
Note

For Windows VMs that do not have a VirtIO driver, you must set the MTU manually by using netsh or a similar tool. This is because the Windows DHCP client does not read the MTU value.

8.2.4. Additional resources

8.3. Exposing a virtual machine by using a service

You can expose a virtual machine within the cluster or outside the cluster by creating a Service object.

8.3.1. About services

A Kubernetes service exposes network access for clients to an application running on a set of pods. Services offer abstraction, load balancing, and, in the case of the NodePort and LoadBalancer types, exposure to the outside world.

ClusterIP
Exposes the service on an internal IP address and as a DNS name to other applications within the cluster. A single service can map to multiple virtual machines. When a client tries to connect to the service, the client’s request is load balanced among available backends. ClusterIP is the default service type.
NodePort
Exposes the service on the same port of each selected node in the cluster. NodePort makes a port accessible from outside the cluster, as long as the node itself is externally accessible to the client.
LoadBalancer
Creates an external load balancer in the current cloud (if supported) and assigns a fixed, external IP address to the service.
Note

For on-premise clusters, you can configure a load-balancing service by deploying the MetalLB Operator.

8.3.2. Dual-stack support

If IPv4 and IPv6 dual-stack networking is enabled for your cluster, you can create a service that uses IPv4, IPv6, or both, by defining the spec.ipFamilyPolicy and the spec.ipFamilies fields in the Service object.

The spec.ipFamilyPolicy field can be set to one of the following values:

SingleStack
The control plane assigns a cluster IP address for the service based on the first configured service cluster IP range.
PreferDualStack
The control plane assigns both IPv4 and IPv6 cluster IP addresses for the service on clusters that have dual-stack configured.
RequireDualStack
This option fails for clusters that do not have dual-stack networking enabled. For clusters that have dual-stack configured, the behavior is the same as when the value is set to PreferDualStack. The control plane allocates cluster IP addresses from both IPv4 and IPv6 address ranges.

You can define which IP family to use for single-stack or define the order of IP families for dual-stack by setting the spec.ipFamilies field to one of the following array values:

  • [IPv4]
  • [IPv6]
  • [IPv4, IPv6]
  • [IPv6, IPv4]

8.3.3. Creating a service by using the command line

You can create a service and associate it with a virtual machine (VM) by using the command line.

Prerequisites

  • You configured the cluster network to support the service.

Procedure

  1. Edit the VirtualMachine manifest to add the label for service creation:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      running: false
      template:
        metadata:
          labels:
            special: key 1
    # ...
    1
    Add special: key to the spec.template.metadata.labels stanza.
    Note

    Labels on a virtual machine are passed through to the pod. The special: key label must match the label in the spec.selector attribute of the Service manifest.

  2. Save the VirtualMachine manifest file to apply your changes.
  3. Create a Service manifest to expose the VM:

    apiVersion: v1
    kind: Service
    metadata:
      name: example-service
      namespace: example-namespace
    spec:
    # ...
      selector:
        special: key 1
      type: NodePort 2
      ports: 3
        protocol: TCP
        port: 80
        targetPort: 9376
        nodePort: 30000
    1
    Specify the label that you added to the spec.template.metadata.labels stanza of the VirtualMachine manifest.
    2
    Specify ClusterIP, NodePort, or LoadBalancer.
    3
    Specifies a collection of network ports and protocols that you want to expose from the virtual machine.
  4. Save the Service manifest file.
  5. Create the service by running the following command:

    $ oc create -f example-service.yaml
  6. Restart the VM to apply the changes.

Verification

  • Query the Service object to verify that it is available:

    $ oc get service -n example-namespace

8.3.4. Additional resources

8.4. Accessing a virtual machine by using its internal FQDN

You can access a virtual machine (VM) that is connected to the default internal pod network on a stable fully qualified domain name (FQDN) by using headless services.

A Kubernetes headless service is a form of service that does not allocate a cluster IP address to represent a set of pods. Instead of providing a single virtual IP address for the service, a headless service creates a DNS record for each pod associated with the service. You can expose a VM through its FQDN without having to expose a specific TCP or UDP port.

Important

If you created a VM by using the OpenShift Container Platform web console, you can find its internal FQDN listed in the Network tile on the Overview tab of the VirtualMachine details page. For more information about connecting to the VM, see Connecting to a virtual machine by using its internal FQDN.

8.4.1. Creating a headless service in a project by using the CLI

To create a headless service in a namespace, add the clusterIP: None parameter to the service YAML definition.

Prerequisites

  • You have installed the OpenShift CLI (oc).

Procedure

  1. Create a Service manifest to expose the VM, such as the following example:

    apiVersion: v1
    kind: Service
    metadata:
      name: mysubdomain 1
    spec:
      selector:
        expose: me 2
      clusterIP: None 3
      ports: 4
      - protocol: TCP
        port: 1234
        targetPort: 1234
    1
    The name of the service. This must match the spec.subdomain attribute in the VirtualMachine manifest file.
    2
    This service selector must match the expose:me label in the VirtualMachine manifest file.
    3
    Specifies a headless service.
    4
    The list of ports that are exposed by the service. You must define at least one port. This can be any arbitrary value as it does not affect the headless service.
  2. Save the Service manifest file.
  3. Create the service by running the following command:

    $ oc create -f headless_service.yaml

8.4.2. Mapping a virtual machine to a headless service by using the CLI

To connect to a virtual machine (VM) from within the cluster by using its internal fully qualified domain name (FQDN), you must first map the VM to a headless service. Set the spec.hostname and spec.subdomain parameters in the VM configuration file.

If a headless service exists with a name that matches the subdomain, a unique DNS A record is created for the VM in the form of <vm.spec.hostname>.<vm.spec.subdomain>.<vm.metadata.namespace>.svc.cluster.local.

Procedure

  1. Edit the VirtualMachine manifest to add the service selector label and subdomain by running the following command:

    $ oc edit vm <vm_name>

    Example VirtualMachine manifest file

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-fedora
    spec:
      template:
        metadata:
          labels:
            expose: me 1
        spec:
          hostname: "myvm" 2
          subdomain: "mysubdomain" 3
    # ...

    1
    The expose:me label must match the spec.selector attribute of the Service manifest that you previously created.
    2
    If this attribute is not specified, the resulting DNS A record takes the form of <vm.metadata.name>.<vm.spec.subdomain>.<vm.metadata.namespace>.svc.cluster.local.
    3
    The spec.subdomain attribute must match the metadata.name value of the Service object.
  2. Save your changes and exit the editor.
  3. Restart the VM to apply the changes.

8.4.3. Connecting to a virtual machine by using its internal FQDN

You can connect to a virtual machine (VM) by using its internal fully qualified domain name (FQDN).

Prerequisites

  • You have installed the virtctl tool.
  • You have identified the internal FQDN of the VM from the web console or by mapping the VM to a headless service. The internal FQDN has the format <vm.spec.hostname>.<vm.spec.subdomain>.<vm.metadata.namespace>.svc.cluster.local.

Procedure

  1. Connect to the VM console by entering the following command:

    $ virtctl console vm-fedora
  2. To connect to the VM by using the requested FQDN, run the following command:

    $ ping myvm.mysubdomain.<namespace>.svc.cluster.local

    Example output

    PING myvm.mysubdomain.default.svc.cluster.local (10.244.0.57) 56(84) bytes of data.
    64 bytes from myvm.mysubdomain.default.svc.cluster.local (10.244.0.57): icmp_seq=1 ttl=64 time=0.029 ms

    In the preceding example, the DNS entry for myvm.mysubdomain.default.svc.cluster.local points to 10.244.0.57, which is the cluster IP address that is currently assigned to the VM.

8.4.4. Additional resources

8.5. Connecting a virtual machine to a Linux bridge network

By default, OpenShift Virtualization is installed with a single, internal pod network.

You can create a Linux bridge network and attach a virtual machine (VM) to the network by performing the following steps:

  1. Create a Linux bridge node network configuration policy (NNCP).
  2. Create a Linux bridge network attachment definition (NAD) by using the web console or the command line.
  3. Configure the VM to recognize the NAD by using the web console or the command line.

8.5.1. Creating a Linux bridge NNCP

You can create a NodeNetworkConfigurationPolicy (NNCP) manifest for a Linux bridge network.

Prerequisites

  • You have installed the Kubernetes NMState Operator.

Procedure

  • Create the NodeNetworkConfigurationPolicy manifest. This example includes sample values that you must replace with your own information.

    apiVersion: nmstate.io/v1
    kind: NodeNetworkConfigurationPolicy
    metadata:
      name: br1-eth1-policy 1
    spec:
      desiredState:
        interfaces:
          - name: br1 2
            description: Linux bridge with eth1 as a port 3
            type: linux-bridge 4
            state: up 5
            ipv4:
              enabled: false 6
            bridge:
              options:
                stp:
                  enabled: false 7
              port:
                - name: eth1 8
    1
    Name of the policy.
    2
    Name of the interface.
    3
    Optional: Human-readable description of the interface.
    4
    The type of interface. This example creates a bridge.
    5
    The requested state for the interface after creation.
    6
    Disables IPv4 in this example.
    7
    Disables STP in this example.
    8
    The node NIC to which the bridge is attached.

8.5.2. Creating a Linux bridge NAD

You can create a Linux bridge network attachment definition (NAD) by using the OpenShift Container Platform web console or command line.

8.5.2.1. Creating a Linux bridge NAD by using the web console

You can create a network attachment definition (NAD) to provide layer-2 networking to pods and virtual machines by using the OpenShift Container Platform web console.

A Linux bridge network attachment definition is the most efficient method for connecting a virtual machine to a VLAN.

Warning

Configuring IP address management (IPAM) in a network attachment definition for virtual machines is not supported.

Procedure

  1. In the web console, click NetworkingNetworkAttachmentDefinitions.
  2. Click Create Network Attachment Definition.

    Note

    The network attachment definition must be in the same namespace as the pod or virtual machine.

  3. Enter a unique Name and optional Description.
  4. Select CNV Linux bridge from the Network Type list.
  5. Enter the name of the bridge in the Bridge Name field.
  6. Optional: If the resource has VLAN IDs configured, enter the ID numbers in the VLAN Tag Number field.
  7. Optional: Select MAC Spoof Check to enable MAC spoof filtering. This feature provides security against a MAC spoofing attack by allowing only a single MAC address to exit the pod.
  8. Click Create.
8.5.2.2. Creating a Linux bridge NAD by using the command line

You can create a network attachment definition (NAD) to provide layer-2 networking to pods and virtual machines (VMs) by using the command line.

The NAD and the VM must be in the same namespace.

Warning

Configuring IP address management (IPAM) in a network attachment definition for virtual machines is not supported.

Prerequisites

  • The node must support nftables and the nft binary must be deployed to enable MAC spoof check.

Procedure

  1. Add the VM to the NetworkAttachmentDefinition configuration, as in the following example:

    apiVersion: "k8s.cni.cncf.io/v1"
    kind: NetworkAttachmentDefinition
    metadata:
      name: bridge-network 1
      annotations:
        k8s.v1.cni.cncf.io/resourceName: bridge.network.kubevirt.io/bridge-interface 2
    spec:
      config: |
        {
          "cniVersion": "0.3.1",
          "name": "bridge-network", 3
          "type": "bridge", 4
          "bridge": "bridge-interface", 5
          "macspoofchk": false, 6
          "vlan": 100, 7
          "disableContainerInterface": true,
          "preserveDefaultVlan": false 8
        }
    1
    The name for the NetworkAttachmentDefinition object.
    2
    Optional: Annotation key-value pair for node selection, where bridge-interface must match the name of a bridge configured on some nodes. If you add this annotation to your network attachment definition, your virtual machine instances will only run on the nodes that have the bridge-interface bridge connected.
    3
    The name for the configuration. It is recommended to match the configuration name to the name value of the network attachment definition.
    4
    The actual name of the Container Network Interface (CNI) plugin that provides the network for this network attachment definition. Do not change this field unless you want to use a different CNI.
    5
    The name of the Linux bridge configured on the node.
    6
    Optional: A flag to enable the MAC spoof check. When set to true, you cannot change the MAC address of the pod or guest interface. This attribute allows only a single MAC address to exit the pod, which provides security against a MAC spoofing attack.
    7
    Optional: The VLAN tag. No additional VLAN configuration is required on the node network configuration policy.
    8
    Optional: Indicates whether the VM connects to the bridge through the default VLAN. The default value is true.
    Note

    A Linux bridge network attachment definition is the most efficient method for connecting a virtual machine to a VLAN.

  2. Create the network attachment definition:

    $ oc create -f network-attachment-definition.yaml 1
    1
    Where network-attachment-definition.yaml is the file name of the network attachment definition manifest.

Verification

  • Verify that the network attachment definition was created by running the following command:

    $ oc get network-attachment-definition bridge-network

8.5.3. Configuring a VM network interface

You can configure a virtual machine (VM) network interface by using the OpenShift Container Platform web console or command line.

8.5.3.1. Configuring a VM network interface by using the web console

You can configure a network interface for a virtual machine (VM) by using the OpenShift Container Platform web console.

Prerequisites

  • You created a network attachment definition for the network.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Click a VM to view the VirtualMachine details page.
  3. On the Configuration tab, click the Network interfaces tab.
  4. Click Add network interface.
  5. Enter the interface name and select the network attachment definition from the Network list.
  6. Click Save.
  7. Restart the VM to apply the changes.
Networking fields
NameDescription

Name

Name for the network interface controller.

Model

Indicates the model of the network interface controller. Supported values are e1000e and virtio.

Network

List of available network attachment definitions.

Type

List of available binding methods. Select the binding method suitable for the network interface:

  • Default pod network: masquerade
  • Linux bridge network: bridge
  • SR-IOV network: SR-IOV

MAC Address

MAC address for the network interface controller. If a MAC address is not specified, one is assigned automatically.

8.5.3.2. Configuring a VM network interface by using the command line

You can configure a virtual machine (VM) network interface for a bridge network by using the command line.

Prerequisites

  • Shut down the virtual machine before editing the configuration. If you edit a running virtual machine, you must restart the virtual machine for the changes to take effect.

Procedure

  1. Add the bridge interface and the network attachment definition to the VM configuration as in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
    spec:
      template:
        spec:
          domain:
            devices:
              interfaces:
                - bridge: {}
                  name: bridge-net 1
    # ...
          networks:
            - name: bridge-net 2
              multus:
                networkName: a-bridge-network 3
    1
    The name of the bridge interface.
    2
    The name of the network. This value must match the name value of the corresponding spec.template.spec.domain.devices.interfaces entry.
    3
    The name of the network attachment definition.
  2. Apply the configuration:

    $ oc apply -f example-vm.yaml
  3. Optional: If you edited a running virtual machine, you must restart it for the changes to take effect.

8.6. Connecting a virtual machine to an SR-IOV network

You can connect a virtual machine (VM) to a Single Root I/O Virtualization (SR-IOV) network by performing the following steps:

8.6.1. Configuring SR-IOV network devices

The SR-IOV Network Operator adds the SriovNetworkNodePolicy.sriovnetwork.openshift.io CustomResourceDefinition to OpenShift Container Platform. You can configure an SR-IOV network device by creating a SriovNetworkNodePolicy custom resource (CR).

Note

When applying the configuration specified in a SriovNetworkNodePolicy object, the SR-IOV Operator might drain the nodes, and in some cases, reboot nodes. Reboot only happens in the following cases:

  • With Mellanox NICs (mlx5 driver) a node reboot happens every time the number of virtual functions (VFs) increase on a physical function (PF).
  • With Intel NICs, a reboot only happens if the kernel parameters do not include intel_iommu=on and iommu=pt.

It might take several minutes for a configuration change to apply.

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You have access to the cluster as a user with the cluster-admin role.
  • You have installed the SR-IOV Network Operator.
  • You have enough available nodes in your cluster to handle the evicted workload from drained nodes.
  • You have not selected any control plane nodes for SR-IOV network device configuration.

Procedure

  1. Create an SriovNetworkNodePolicy object, and then save the YAML in the <name>-sriov-node-network.yaml file. Replace <name> with the name for this configuration.

    apiVersion: sriovnetwork.openshift.io/v1
    kind: SriovNetworkNodePolicy
    metadata:
      name: <name> 1
      namespace: openshift-sriov-network-operator 2
    spec:
      resourceName: <sriov_resource_name> 3
      nodeSelector:
        feature.node.kubernetes.io/network-sriov.capable: "true" 4
      priority: <priority> 5
      mtu: <mtu> 6
      numVfs: <num> 7
      nicSelector: 8
        vendor: "<vendor_code>" 9
        deviceID: "<device_id>" 10
        pfNames: ["<pf_name>", ...] 11
        rootDevices: ["<pci_bus_id>", "..."] 12
      deviceType: vfio-pci 13
      isRdma: false 14
    1
    Specify a name for the CR object.
    2
    Specify the namespace where the SR-IOV Operator is installed.
    3
    Specify the resource name of the SR-IOV device plugin. You can create multiple SriovNetworkNodePolicy objects for a resource name.
    4
    Specify the node selector to select which nodes are configured. Only SR-IOV network devices on selected nodes are configured. The SR-IOV Container Network Interface (CNI) plugin and device plugin are deployed only on selected nodes.
    5
    Optional: Specify an integer value between 0 and 99. A smaller number gets higher priority, so a priority of 10 is higher than a priority of 99. The default value is 99.
    6
    Optional: Specify a value for the maximum transmission unit (MTU) of the virtual function. The maximum MTU value can vary for different NIC models.
    7
    Specify the number of the virtual functions (VF) to create for the SR-IOV physical network device. For an Intel network interface controller (NIC), the number of VFs cannot be larger than the total VFs supported by the device. For a Mellanox NIC, the number of VFs cannot be larger than 127.
    8
    The nicSelector mapping selects the Ethernet device for the Operator to configure. You do not need to specify values for all the parameters. It is recommended to identify the Ethernet adapter with enough precision to minimize the possibility of selecting an Ethernet device unintentionally. If you specify rootDevices, you must also specify a value for vendor, deviceID, or pfNames. If you specify both pfNames and rootDevices at the same time, ensure that they point to an identical device.
    9
    Optional: Specify the vendor hex code of the SR-IOV network device. The only allowed values are either 8086 or 15b3.
    10
    Optional: Specify the device hex code of SR-IOV network device. The only allowed values are 158b, 1015, 1017.
    11
    Optional: The parameter accepts an array of one or more physical function (PF) names for the Ethernet device.
    12
    The parameter accepts an array of one or more PCI bus addresses for the physical function of the Ethernet device. Provide the address in the following format: 0000:02:00.1.
    13
    The vfio-pci driver type is required for virtual functions in OpenShift Virtualization.
    14
    Optional: Specify whether to enable remote direct memory access (RDMA) mode. For a Mellanox card, set isRdma to false. The default value is false.
    Note

    If isRDMA flag is set to true, you can continue to use the RDMA enabled VF as a normal network device. A device can be used in either mode.

  2. Optional: Label the SR-IOV capable cluster nodes with SriovNetworkNodePolicy.Spec.NodeSelector if they are not already labeled. For more information about labeling nodes, see "Understanding how to update labels on nodes".
  3. Create the SriovNetworkNodePolicy object:

    $ oc create -f <name>-sriov-node-network.yaml

    where <name> specifies the name for this configuration.

    After applying the configuration update, all the pods in sriov-network-operator namespace transition to the Running status.

  4. To verify that the SR-IOV network device is configured, enter the following command. Replace <node_name> with the name of a node with the SR-IOV network device that you just configured.

    $ oc get sriovnetworknodestates -n openshift-sriov-network-operator <node_name> -o jsonpath='{.status.syncStatus}'

8.6.2. Configuring SR-IOV additional network

You can configure an additional network that uses SR-IOV hardware by creating an SriovNetwork object.

When you create an SriovNetwork object, the SR-IOV Network Operator automatically creates a NetworkAttachmentDefinition object.

Note

Do not modify or delete an SriovNetwork object if it is attached to pods or virtual machines in a running state.

Prerequisites

  • Install the OpenShift CLI (oc).
  • Log in as a user with cluster-admin privileges.

Procedure

  1. Create the following SriovNetwork object, and then save the YAML in the <name>-sriov-network.yaml file. Replace <name> with a name for this additional network.
apiVersion: sriovnetwork.openshift.io/v1
kind: SriovNetwork
metadata:
  name: <name> 1
  namespace: openshift-sriov-network-operator 2
spec:
  resourceName: <sriov_resource_name> 3
  networkNamespace: <target_namespace> 4
  vlan: <vlan> 5
  spoofChk: "<spoof_check>" 6
  linkState: <link_state> 7
  maxTxRate: <max_tx_rate> 8
  minTxRate: <min_rx_rate> 9
  vlanQoS: <vlan_qos> 10
  trust: "<trust_vf>" 11
  capabilities: <capabilities> 12
1
Replace <name> with a name for the object. The SR-IOV Network Operator creates a NetworkAttachmentDefinition object with same name.
2
Specify the namespace where the SR-IOV Network Operator is installed.
3
Replace <sriov_resource_name> with the value for the .spec.resourceName parameter from the SriovNetworkNodePolicy object that defines the SR-IOV hardware for this additional network.
4
Replace <target_namespace> with the target namespace for the SriovNetwork. Only pods or virtual machines in the target namespace can attach to the SriovNetwork.
5
Optional: Replace <vlan> with a Virtual LAN (VLAN) ID for the additional network. The integer value must be from 0 to 4095. The default value is 0.
6
Optional: Replace <spoof_check> with the spoof check mode of the VF. The allowed values are the strings "on" and "off".
Important

You must enclose the value you specify in quotes or the CR is rejected by the SR-IOV Network Operator.

7
Optional: Replace <link_state> with the link state of virtual function (VF). Allowed value are enable, disable and auto.
8
Optional: Replace <max_tx_rate> with a maximum transmission rate, in Mbps, for the VF.
9
Optional: Replace <min_tx_rate> with a minimum transmission rate, in Mbps, for the VF. This value should always be less than or equal to Maximum transmission rate.
Note

Intel NICs do not support the minTxRate parameter. For more information, see BZ#1772847.

10
Optional: Replace <vlan_qos> with an IEEE 802.1p priority level for the VF. The default value is 0.
11
Optional: Replace <trust_vf> with the trust mode of the VF. The allowed values are the strings "on" and "off".
Important

You must enclose the value you specify in quotes or the CR is rejected by the SR-IOV Network Operator.

12
Optional: Replace <capabilities> with the capabilities to configure for this network.
  1. To create the object, enter the following command. Replace <name> with a name for this additional network.

    $ oc create -f <name>-sriov-network.yaml
  2. Optional: To confirm that the NetworkAttachmentDefinition object associated with the SriovNetwork object that you created in the previous step exists, enter the following command. Replace <namespace> with the namespace you specified in the SriovNetwork object.

    $ oc get net-attach-def -n <namespace>

8.6.3. Connecting a virtual machine to an SR-IOV network by using the command line

You can connect the virtual machine (VM) to the SR-IOV network by including the network details in the VM configuration.

Procedure

  1. Add the SR-IOV network details to the spec.domain.devices.interfaces and spec.networks stanzas of the VM configuration as in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
    spec:
      domain:
        devices:
          interfaces:
          - name: nic1 1
            sriov: {}
      networks:
      - name: nic1 2
        multus:
            networkName: sriov-network 3
    # ...
    1
    Specify a unique name for the SR-IOV interface.
    2
    Specify the name of the SR-IOV interface. This must be the same as the interfaces.name that you defined earlier.
    3
    Specify the name of the SR-IOV network attachment definition.
  2. Apply the virtual machine configuration:

    $ oc apply -f <vm_sriov>.yaml 1
    1
    The name of the virtual machine YAML file.

8.6.4. Connecting a VM to an SR-IOV network by using the web console

You can connect a VM to the SR-IOV network by including the network details in the VM configuration.

Prerequisites

  • You must create a network attachment definition for the network.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Click a VM to view the VirtualMachine details page.
  3. On the Configuration tab, click the Network interfaces tab.
  4. Click Add network interface.
  5. Enter the interface name.
  6. Select an SR-IOV network attachment definition from the Network list.
  7. Select SR-IOV from the Type list.
  8. Optional: Add a network Model or Mac address.
  9. Click Save.
  10. Restart or live-migrate the VM to apply the changes.

8.6.5. Additional resources

8.7. Using DPDK with SR-IOV

The Data Plane Development Kit (DPDK) provides a set of libraries and drivers for fast packet processing.

You can configure clusters and virtual machines (VMs) to run DPDK workloads over SR-IOV networks.

8.7.1. Configuring a cluster for DPDK workloads

You can configure an OpenShift Container Platform cluster to run Data Plane Development Kit (DPDK) workloads for improved network performance.

Prerequisites

  • You have access to the cluster as a user with cluster-admin permissions.
  • You have installed the OpenShift CLI (oc).
  • You have installed the SR-IOV Network Operator.
  • You have installed the Node Tuning Operator.

Procedure

  1. Map your compute nodes topology to determine which Non-Uniform Memory Access (NUMA) CPUs are isolated for DPDK applications and which ones are reserved for the operating system (OS).
  2. If your OpenShift Container Platform cluster uses separate control plane and compute nodes for high-availability:

    1. Label a subset of the compute nodes with a custom role; for example, worker-dpdk:

      $ oc label node <node_name> node-role.kubernetes.io/worker-dpdk=""
    2. Create a new MachineConfigPool manifest that contains the worker-dpdk label in the spec.machineConfigSelector object:

      Example MachineConfigPool manifest

      apiVersion: machineconfiguration.openshift.io/v1
      kind: MachineConfigPool
      metadata:
        name: worker-dpdk
        labels:
          machineconfiguration.openshift.io/role: worker-dpdk
      spec:
        machineConfigSelector:
          matchExpressions:
            - key: machineconfiguration.openshift.io/role
              operator: In
              values:
                - worker
                - worker-dpdk
        nodeSelector:
          matchLabels:
            node-role.kubernetes.io/worker-dpdk: ""

  3. Create a PerformanceProfile manifest that applies to the labeled nodes and the machine config pool that you created in the previous steps. The performance profile specifies the CPUs that are isolated for DPDK applications and the CPUs that are reserved for house keeping.

    Example PerformanceProfile manifest

    apiVersion: performance.openshift.io/v2
    kind: PerformanceProfile
    metadata:
      name: profile-1
    spec:
      cpu:
        isolated: 4-39,44-79
        reserved: 0-3,40-43
      globallyDisableIrqLoadBalancing: true
      hugepages:
        defaultHugepagesSize: 1G
        pages:
        - count: 8
          node: 0
          size: 1G
      net:
        userLevelNetworking: true
      nodeSelector:
        node-role.kubernetes.io/worker-dpdk: ""
      numa:
        topologyPolicy: single-numa-node

    Note

    The compute nodes automatically restart after you apply the MachineConfigPool and PerformanceProfile manifests.

  4. Retrieve the name of the generated RuntimeClass resource from the status.runtimeClass field of the PerformanceProfile object:

    $ oc get performanceprofiles.performance.openshift.io profile-1 -o=jsonpath='{.status.runtimeClass}{"\n"}'
  5. Set the previously obtained RuntimeClass name as the default container runtime class for the virt-launcher pods by editing the HyperConverged custom resource (CR):

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
        --type='json' -p='[{"op": "add", "path": "/spec/defaultRuntimeClass", "value":"<runtimeclass-name>"}]'
    Note

    Editing the HyperConverged CR changes a global setting that affects all VMs that are created after the change is applied.

  6. If your DPDK-enabled compute nodes use Simultaneous multithreading (SMT), enable the AlignCPUs enabler by editing the HyperConverged CR:

    $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
        --type='json' -p='[{"op": "replace", "path": "/spec/featureGates/alignCPUs", "value": true}]'
    Note

    Enabling AlignCPUs allows OpenShift Virtualization to request up to two additional dedicated CPUs to bring the total CPU count to an even parity when using emulator thread isolation.

  7. Create an SriovNetworkNodePolicy object with the spec.deviceType field set to vfio-pci:

    Example SriovNetworkNodePolicy manifest

    apiVersion: sriovnetwork.openshift.io/v1
    kind: SriovNetworkNodePolicy
    metadata:
      name: policy-1
      namespace: openshift-sriov-network-operator
    spec:
      resourceName: intel_nics_dpdk
      deviceType: vfio-pci
      mtu: 9000
      numVfs: 4
      priority: 99
      nicSelector:
        vendor: "8086"
        deviceID: "1572"
        pfNames:
          - eno3
        rootDevices:
          - "0000:19:00.2"
      nodeSelector:
        feature.node.kubernetes.io/network-sriov.capable: "true"

8.7.1.1. Removing a custom machine config pool for high-availability clusters

You can delete a custom machine config pool that you previously created for your high-availability cluster.

Prerequisites

  • You have access to the cluster as a user with cluster-admin permissions.
  • You have installed the OpenShift CLI (oc).
  • You have created a custom machine config pool by labeling a subset of the compute nodes with a custom role and creating a MachineConfigPool manifest with that label.

Procedure

  1. Remove the worker-dpdk label from the compute nodes by running the following command:

    $ oc label node <node_name> node-role.kubernetes.io/worker-dpdk-
  2. Delete the MachineConfigPool manifest that contains the worker-dpdk label by entering the following command:

    $ oc delete mcp worker-dpdk

8.7.2. Configuring a project for DPDK workloads

You can configure the project to run DPDK workloads on SR-IOV hardware.

Prerequisites

  • Your cluster is configured to run DPDK workloads.

Procedure

  1. Create a namespace for your DPDK applications:

    $ oc create ns dpdk-checkup-ns
  2. Create an SriovNetwork object that references the SriovNetworkNodePolicy object. When you create an SriovNetwork object, the SR-IOV Network Operator automatically creates a NetworkAttachmentDefinition object.

    Example SriovNetwork manifest

    apiVersion: sriovnetwork.openshift.io/v1
    kind: SriovNetwork
    metadata:
      name: dpdk-sriovnetwork
      namespace: openshift-sriov-network-operator
    spec:
      ipam: |
        {
          "type": "host-local",
          "subnet": "10.56.217.0/24",
          "rangeStart": "10.56.217.171",
          "rangeEnd": "10.56.217.181",
          "routes": [{
            "dst": "0.0.0.0/0"
          }],
          "gateway": "10.56.217.1"
        }
      networkNamespace: dpdk-checkup-ns 1
      resourceName: intel_nics_dpdk 2
      spoofChk: "off"
      trust: "on"
      vlan: 1019

    1
    The namespace where the NetworkAttachmentDefinition object is deployed.
    2
    The value of the spec.resourceName attribute of the SriovNetworkNodePolicy object that was created when configuring the cluster for DPDK workloads.
  3. Optional: Run the virtual machine latency checkup to verify that the network is properly configured.
  4. Optional: Run the DPDK checkup to verify that the namespace is ready for DPDK workloads.

8.7.3. Configuring a virtual machine for DPDK workloads

You can run Data Packet Development Kit (DPDK) workloads on virtual machines (VMs) to achieve lower latency and higher throughput for faster packet processing in the user space. DPDK uses the SR-IOV network for hardware-based I/O sharing.

Prerequisites

  • Your cluster is configured to run DPDK workloads.
  • You have created and configured the project in which the VM will run.

Procedure

  1. Edit the VirtualMachine manifest to include information about the SR-IOV network interface, CPU topology, CRI-O annotations, and huge pages:

    Example VirtualMachine manifest

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: rhel-dpdk-vm
    spec:
      running: true
      template:
        metadata:
          annotations:
            cpu-load-balancing.crio.io: disable 1
            cpu-quota.crio.io: disable 2
            irq-load-balancing.crio.io: disable 3
        spec:
          domain:
            cpu:
              sockets: 1 4
              cores: 5 5
              threads: 2
              dedicatedCpuPlacement: true
              isolateEmulatorThread: true
            interfaces:
              - masquerade: {}
                name: default
              - model: virtio
                name: nic-east
                pciAddress: '0000:07:00.0'
                sriov: {}
              networkInterfaceMultiqueue: true
              rng: {}
          memory:
            hugepages:
              pageSize: 1Gi 6
              guest: 8Gi
          networks:
            - name: default
              pod: {}
            - multus:
                networkName: dpdk-net 7
              name: nic-east
    # ...

    1
    This annotation specifies that load balancing is disabled for CPUs that are used by the container.
    2
    This annotation specifies that the CPU quota is disabled for CPUs that are used by the container.
    3
    This annotation specifies that Interrupt Request (IRQ) load balancing is disabled for CPUs that are used by the container.
    4
    The number of sockets inside the VM. This field must be set to 1 for the CPUs to be scheduled from the same Non-Uniform Memory Access (NUMA) node.
    5
    The number of cores inside the VM. This must be a value greater than or equal to 1. In this example, the VM is scheduled with 5 hyper-threads or 10 CPUs.
    6
    The size of the huge pages. The possible values for x86-64 architecture are 1Gi and 2Mi. In this example, the request is for 8 huge pages of size 1Gi.
    7
    The name of the SR-IOV NetworkAttachmentDefinition object.
  2. Save and exit the editor.
  3. Apply the VirtualMachine manifest:

    $ oc apply -f <file_name>.yaml
  4. Configure the guest operating system. The following example shows the configuration steps for RHEL 9 operating system:

    1. Configure huge pages by using the GRUB bootloader command-line interface. In the following example, 8 1G huge pages are specified.

      $ grubby --update-kernel=ALL --args="default_hugepagesz=1GB hugepagesz=1G hugepages=8"
    2. To achieve low-latency tuning by using the cpu-partitioning profile in the TuneD application, run the following commands:

      $ dnf install -y tuned-profiles-cpu-partitioning
      $ echo isolated_cores=2-9 > /etc/tuned/cpu-partitioning-variables.conf

      The first two CPUs (0 and 1) are set aside for house keeping tasks and the rest are isolated for the DPDK application.

      $ tuned-adm profile cpu-partitioning
    3. Override the SR-IOV NIC driver by using the driverctl device driver control utility:

      $ dnf install -y driverctl
      $ driverctl set-override 0000:07:00.0 vfio-pci
  5. Restart the VM to apply the changes.

8.8. Connecting a virtual machine to an OVN-Kubernetes secondary network

You can connect a virtual machine (VM) to an OVN-Kubernetes secondary network. OpenShift Virtualization supports the layer2 and localnet topologies for OVN-Kubernetes.

  • A layer2 topology connects workloads by a cluster-wide logical switch. The OVN-Kubernetes Container Network Interface (CNI) plugin uses the Geneve (Generic Network Virtualization Encapsulation) protocol to create an overlay network between nodes. You can use this overlay network to connect VMs on different nodes, without having to configure any additional physical networking infrastructure.
  • A localnet topology connects the secondary network to the physical underlay. This enables both east-west cluster traffic and access to services running outside the cluster, but it requires additional configuration of the underlying Open vSwitch (OVS) system on cluster nodes.
Note

An OVN-Kubernetes secondary network is compatible with the multi-network policy API which provides the MultiNetworkPolicy custom resource definition (CRD) to control traffic flow to and from VMs. You can use the ipBlock attribute to define network policy ingress and egress rules for specific CIDR blocks.

To configure an OVN-Kubernetes secondary network and attach a VM to that network, perform the following steps:

  1. Configure an OVN-Kubernetes secondary network by creating a network attachment definition (NAD).

    Note

    For localnet topology, you must configure an OVS bridge by creating a NodeNetworkConfigurationPolicy object before creating the NAD.

  2. Connect the VM to the OVN-Kubernetes secondary network by adding the network details to the VM specification.

8.8.1. Creating an OVN-Kubernetes NAD

You can create an OVN-Kubernetes network attachment definition (NAD) by using the OpenShift Container Platform web console or the CLI.

Note

Configuring IP address management (IPAM) in a network attachment definition for virtual machines is not supported.

8.8.1.1. Creating a NAD for layer 2 topology using the CLI

You can create a network attachment definition (NAD) which describes how to attach a pod to the layer 2 overlay network.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.
  • You have installed the OpenShift CLI (oc).

Procedure

  1. Create a NetworkAttachmentDefinition object:

    apiVersion: k8s.cni.cncf.io/v1
    kind: NetworkAttachmentDefinition
    metadata:
      name: l2-network
      namespace: my-namespace
    spec:
      config: |-
        {
                "cniVersion": "0.3.1", 1
                "name": "my-namespace-l2-network", 2
                "type": "ovn-k8s-cni-overlay", 3
                "topology":"layer2", 4
                "mtu": 1300, 5
                "netAttachDefName": "my-namespace/l2-network" 6
        }
    1
    The CNI specification version. The required value is 0.3.1.
    2
    The name of the network. This attribute is not namespaced. For example, you can have a network named l2-network referenced from two different NetworkAttachmentDefinition objects that exist in two different namespaces. This feature is useful to connect VMs in different namespaces.
    3
    The name of the CNI plug-in to be configured. The required value is ovn-k8s-cni-overlay.
    4
    The topological configuration for the network. The required value is layer2.
    5
    Optional: The maximum transmission unit (MTU) value. The default value is automatically set by the kernel.
    6
    The value of the namespace and name fields in the metadata stanza of the NetworkAttachmentDefinition object.
    Note

    The above example configures a cluster-wide overlay without a subnet defined. This means that the logical switch implementing the network only provides layer 2 communication. You must configure an IP address when you create the virtual machine by either setting a static IP address or by deploying a DHCP server on the network for a dynamic IP address.

  2. Apply the manifest:

    $ oc apply -f <filename>.yaml
8.8.1.2. Creating a NAD for localnet topology using the CLI

You can create a network attachment definition (NAD) which describes how to attach a pod to the underlying physical network.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.
  • You have installed the OpenShift CLI (oc).
  • You have installed the Kubernetes NMState Operator.

Procedure

  1. Create a NodeNetworkConfigurationPolicy object to map the OVN-Kubernetes secondary network to an Open vSwitch (OVS) bridge:

    apiVersion: nmstate.io/v1
    kind: NodeNetworkConfigurationPolicy
    metadata:
      name: mapping 1
    spec:
      nodeSelector:
        node-role.kubernetes.io/worker: '' 2
      desiredState:
        ovn:
          bridge-mappings:
          - localnet: localnet-network 3
            bridge: br-ex 4
            state: present 5
    1
    The name of the configuration object.
    2
    Specifies the nodes to which the node network configuration policy is to be applied. The recommended node selector value is node-role.kubernetes.io/worker: ''.
    3
    The name of the additional network from which traffic is forwarded to the OVS bridge. This attribute must match the value of the spec.config.name field of the NetworkAttachmentDefinition object that defines the OVN-Kubernetes additional network.
    4
    The name of the OVS bridge on the node. This value is required if the state attribute is present.
    5
    The state of the mapping. Must be either present to add the mapping or absent to remove the mapping. The default value is present.
  2. Create a NetworkAttachmentDefinition object:

    apiVersion: k8s.cni.cncf.io/v1
    kind: NetworkAttachmentDefinition
    metadata:
      name: localnet-network
      namespace: default
    spec:
      config: |-
        {
                "cniVersion": "0.3.1", 1
                "name": "localnet-network", 2
                "type": "ovn-k8s-cni-overlay", 3
                "topology": "localnet", 4
                "netAttachDefName": "default/localnet-network" 5
        }
    1
    The CNI specification version. The required value is 0.3.1.
    2
    The name of the network. This attribute must match the value of the spec.desiredState.ovn.bridge-mappings.localnet field of the NodeNetworkConfigurationPolicy object that defines the OVS bridge mapping.
    3
    The name of the CNI plug-in to be configured. The required value is ovn-k8s-cni-overlay.
    4
    The topological configuration for the network. The required value is localnet.
    5
    The value of the namespace and name fields in the metadata stanza of the NetworkAttachmentDefinition object.
  3. Apply the manifest:

    $ oc apply -f <filename>.yaml
8.8.1.3. Creating a NAD for layer 2 topology by using the web console

You can create a network attachment definition (NAD) that describes how to attach a pod to the layer 2 overlay network.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.

Procedure

  1. Go to NetworkingNetworkAttachmentDefinitions in the web console.
  2. Click Create Network Attachment Definition. The network attachment definition must be in the same namespace as the pod or virtual machine using it.
  3. Enter a unique Name and optional Description.
  4. Select OVN Kubernetes L2 overlay network from the Network Type list.
  5. Click Create.
8.8.1.4. Creating a NAD for localnet topology using the web console

You can create a network attachment definition (NAD) to connect workloads to a physical network by using the OpenShift Container Platform web console.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.
  • Use nmstate to configure the localnet to OVS bridge mappings.

Procedure

  1. Navigate to NetworkingNetworkAttachmentDefinitions in the web console.
  2. Click Create Network Attachment Definition. The network attachment definition must be in the same namespace as the pod or virtual machine using it.
  3. Enter a unique Name and optional Description.
  4. Select OVN Kubernetes secondary localnet network from the Network Type list.
  5. Enter the name of your pre-configured localnet identifier in the Bridge mapping field.
  6. Optional: You can explicitly set MTU to the specified value. The default value is chosen by the kernel.
  7. Optional: Encapsulate the traffic in a VLAN. The default value is none.
  8. Click Create.

8.8.2. Attaching a virtual machine to the OVN-Kubernetes secondary network

You can attach a virtual machine (VM) to the OVN-Kubernetes secondary network interface by using the OpenShift Container Platform web console or the CLI.

8.8.2.1. Attaching a virtual machine to an OVN-Kubernetes secondary network using the CLI

You can connect a virtual machine (VM) to the OVN-Kubernetes secondary network by including the network details in the VM configuration.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges.
  • You have installed the OpenShift CLI (oc).

Procedure

  1. Edit the VirtualMachine manifest to add the OVN-Kubernetes secondary network interface details, as in the following example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-server
    spec:
      running: true
      template:
        spec:
          domain:
            devices:
              interfaces:
              - name: secondary 1
                bridge: {}
            resources:
              requests:
                memory: 1024Mi
          networks:
          - name: secondary  2
            multus:
              networkName: <nad_name> 3
          nodeSelector:
            node-role.kubernetes.io/worker: '' 4
    # ...
    1
    The name of the OVN-Kubernetes secondary interface.
    2
    The name of the network. This must match the value of the spec.template.spec.domain.devices.interfaces.name field.
    3
    The name of the NetworkAttachmentDefinition object.
    4
    Specifies the nodes on which the VM can be scheduled. The recommended node selector value is node-role.kubernetes.io/worker: ''.
  2. Apply the VirtualMachine manifest:

    $ oc apply -f <filename>.yaml
  3. Optional: If you edited a running virtual machine, you must restart it for the changes to take effect.

8.8.3. Additional resources

8.9. Hot plugging secondary network interfaces

You can add or remove secondary network interfaces without stopping your virtual machine (VM). OpenShift Virtualization supports hot plugging and hot unplugging for secondary interfaces that use bridge binding and the VirtIO device driver. OpenShift Virtualization also supports hot plugging secondary interfaces that use SR-IOV binding.

Note

Hot unplugging is not supported for Single Root I/O Virtualization (SR-IOV) interfaces.

8.9.1. VirtIO limitations

Each VirtIO interface uses one of the limited Peripheral Connect Interface (PCI) slots in the VM. There are a total of 32 slots available. The PCI slots are also used by other devices and must be reserved in advance, therefore slots might not be available on demand. OpenShift Virtualization reserves up to four slots for hot plugging interfaces. This includes any existing plugged network interfaces. For example, if your VM has two existing plugged interfaces, you can hot plug two more network interfaces.

Note

The actual number of slots available for hot plugging also depends on the machine type. For example, the default PCI topology for the q35 machine type supports hot plugging one additional PCIe device. For more information on PCI topology and hot plug support, see the libvirt documentation.

If you restart the VM after hot plugging an interface, that interface becomes part of the standard network interfaces.

8.9.2. Hot plugging a secondary network interface by using the CLI

Hot plug a secondary network interface to a virtual machine (VM) while the VM is running.

Prerequisites

  • A network attachment definition is configured in the same namespace as your VM.
  • You have installed the virtctl tool.
  • You have installed the OpenShift CLI (oc).

Procedure

  1. If the VM to which you want to hot plug the network interface is not running, start it by using the following command:

    $ virtctl start <vm_name> -n <namespace>
  2. Use the following command to add the new network interface to the running VM. Editing the VM specification adds the new network interface to the VM and virtual machine instance (VMI) configuration but does not attach it to the running VM.

    $ oc edit vm <vm_name>

    Example VM configuration

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-fedora
    template:
      spec:
        domain:
          devices:
            interfaces:
            - name: defaultnetwork
              masquerade: {}
            # new interface
            - name: <secondary_nic> 1
              bridge: {}
        networks:
        - name: defaultnetwork
          pod: {}
        # new network
        - name: <secondary_nic> 2
          multus:
            networkName: <nad_name> 3
    # ...

    1
    Specifies the name of the new network interface.
    2
    Specifies the name of the network. This must be the same as the name of the new network interface that you defined in the template.spec.domain.devices.interfaces list.
    3
    Specifies the name of the NetworkAttachmentDefinition object.
  3. To attach the network interface to the running VM, live migrate the VM by running the following command:

    $ virtctl migrate <vm_name>

Verification

  1. Verify that the VM live migration is successful by using the following command:

    $ oc get VirtualMachineInstanceMigration -w

    Example output

    NAME                        PHASE             VMI
    kubevirt-migrate-vm-lj62q   Scheduling        vm-fedora
    kubevirt-migrate-vm-lj62q   Scheduled         vm-fedora
    kubevirt-migrate-vm-lj62q   PreparingTarget   vm-fedora
    kubevirt-migrate-vm-lj62q   TargetReady       vm-fedora
    kubevirt-migrate-vm-lj62q   Running           vm-fedora
    kubevirt-migrate-vm-lj62q   Succeeded         vm-fedora

  2. Verify that the new interface is added to the VM by checking the VMI status:

    $ oc get vmi vm-fedora -ojsonpath="{ @.status.interfaces }"

    Example output

    [
      {
        "infoSource": "domain, guest-agent",
        "interfaceName": "eth0",
        "ipAddress": "10.130.0.195",
        "ipAddresses": [
          "10.130.0.195",
          "fd02:0:0:3::43c"
        ],
        "mac": "52:54:00:0e:ab:25",
        "name": "default",
        "queueCount": 1
      },
      {
        "infoSource": "domain, guest-agent, multus-status",
        "interfaceName": "eth1",
        "mac": "02:d8:b8:00:00:2a",
        "name": "bridge-interface", 1
        "queueCount": 1
      }
    ]

    1
    The hot plugged interface appears in the VMI status.

8.9.3. Hot unplugging a secondary network interface by using the CLI

You can remove a secondary network interface from a running virtual machine (VM).

Note

Hot unplugging is not supported for Single Root I/O Virtualization (SR-IOV) interfaces.

Prerequisites

  • Your VM must be running.
  • The VM must be created on a cluster running OpenShift Virtualization 4.14 or later.
  • The VM must have a bridge network interface attached.

Procedure

  1. Edit the VM specification to hot unplug a secondary network interface. Setting the interface state to absent detaches the network interface from the guest, but the interface still exists in the pod.

    $ oc edit vm <vm_name>

    Example VM configuration

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: vm-fedora
    template:
      spec:
        domain:
          devices:
            interfaces:
              - name: defaultnetwork
                masquerade: {}
              # set the interface state to absent
              - name: <secondary_nic>
                state: absent 1
                bridge: {}
        networks:
          - name: defaultnetwork
            pod: {}
          - name: <secondary_nic>
            multus:
              networkName: <nad_name>
    # ...

    1
    Set the interface state to absent to detach it from the running VM. Removing the interface details from the VM specification does not hot unplug the secondary network interface.
  2. Remove the interface from the pod by migrating the VM:

    $ virtctl migrate <vm_name>

8.9.4. Additional resources

8.10. Connecting a virtual machine to a service mesh

OpenShift Virtualization is now integrated with OpenShift Service Mesh. You can monitor, visualize, and control traffic between pods that run virtual machine workloads on the default pod network with IPv4.

8.10.1. Adding a virtual machine to a service mesh

To add a virtual machine (VM) workload to a service mesh, enable automatic sidecar injection in the VM configuration file by setting the sidecar.istio.io/inject annotation to true. Then expose your VM as a service to view your application in the mesh.

Important

To avoid port conflicts, do not use ports used by the Istio sidecar proxy. These include ports 15000, 15001, 15006, 15008, 15020, 15021, and 15090.

Prerequisites

  • You installed the Service Mesh Operators.
  • You created the Service Mesh control plane.
  • You added the VM project to the Service Mesh member roll.

Procedure

  1. Edit the VM configuration file to add the sidecar.istio.io/inject: "true" annotation:

    Example configuration file

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      labels:
        kubevirt.io/vm: vm-istio
      name: vm-istio
    spec:
      runStrategy: Always
      template:
        metadata:
          labels:
            kubevirt.io/vm: vm-istio
            app: vm-istio 1
          annotations:
            sidecar.istio.io/inject: "true" 2
        spec:
          domain:
            devices:
              interfaces:
              - name: default
                masquerade: {} 3
              disks:
              - disk:
                  bus: virtio
                name: containerdisk
              - disk:
                  bus: virtio
                name: cloudinitdisk
            resources:
              requests:
                memory: 1024M
          networks:
          - name: default
            pod: {}
          terminationGracePeriodSeconds: 180
          volumes:
          - containerDisk:
              image: registry:5000/kubevirt/fedora-cloud-container-disk-demo:devel
            name: containerdisk

    1
    The key/value pair (label) that must be matched to the service selector attribute.
    2
    The annotation to enable automatic sidecar injection.
    3
    The binding method (masquerade mode) for use with the default pod network.
  2. Apply the VM configuration:

    $ oc apply -f <vm_name>.yaml 1
    1
    The name of the virtual machine YAML file.
  3. Create a Service object to expose your VM to the service mesh.

    apiVersion: v1
    kind: Service
    metadata:
      name: vm-istio
    spec:
      selector:
        app: vm-istio 1
      ports:
        - port: 8080
          name: http
          protocol: TCP
    1
    The service selector that determines the set of pods targeted by a service. This attribute corresponds to the spec.metadata.labels field in the VM configuration file. In the above example, the Service object named vm-istio targets TCP port 8080 on any pod with the label app=vm-istio.
  4. Create the service:

    $ oc create -f <service_name>.yaml 1
    1
    The name of the service YAML file.

8.10.2. Additional resources

8.11. Configuring a dedicated network for live migration

You can configure a dedicated Multus network for live migration. A dedicated network minimizes the effects of network saturation on tenant workloads during live migration.

8.11.1. Configuring a dedicated secondary network for live migration

To configure a dedicated secondary network for live migration, you must first create a bridge network attachment definition (NAD) by using the CLI. Then, you add the name of the NetworkAttachmentDefinition object to the HyperConverged custom resource (CR).

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You logged in to the cluster as a user with the cluster-admin role.
  • Each node has at least two Network Interface Cards (NICs).
  • The NICs for live migration are connected to the same VLAN.

Procedure

  1. Create a NetworkAttachmentDefinition manifest according to the following example:

    Example configuration file

    apiVersion: "k8s.cni.cncf.io/v1"
    kind: NetworkAttachmentDefinition
    metadata:
      name: my-secondary-network 1
      namespace: openshift-cnv
    spec:
      config: '{
        "cniVersion": "0.3.1",
        "name": "migration-bridge",
        "type": "macvlan",
        "master": "eth1", 2
        "mode": "bridge",
        "ipam": {
          "type": "whereabouts", 3
          "range": "10.200.5.0/24" 4
        }
      }'

    1
    Specify the name of the NetworkAttachmentDefinition object.
    2
    Specify the name of the NIC to be used for live migration.
    3
    Specify the name of the CNI plugin that provides the network for the NAD.
    4
    Specify an IP address range for the secondary network. This range must not overlap the IP addresses of the main network.
  2. Open the HyperConverged CR in your default editor by running the following command:

    oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  3. Add the name of the NetworkAttachmentDefinition object to the spec.liveMigrationConfig stanza of the HyperConverged CR:

    Example HyperConverged manifest

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      liveMigrationConfig:
        completionTimeoutPerGiB: 800
        network: <network> 1
        parallelMigrationsPerCluster: 5
        parallelOutboundMigrationsPerNode: 2
        progressTimeout: 150
    # ...

    1
    Specify the name of the Multus NetworkAttachmentDefinition object to be used for live migrations.
  4. Save your changes and exit the editor. The virt-handler pods restart and connect to the secondary network.

Verification

  • When the node that the virtual machine runs on is placed into maintenance mode, the VM automatically migrates to another node in the cluster. You can verify that the migration occurred over the secondary network and not the default pod network by checking the target IP address in the virtual machine instance (VMI) metadata.

    $ oc get vmi <vmi_name> -o jsonpath='{.status.migrationState.targetNodeAddress}'

8.11.2. Selecting a dedicated network by using the web console

You can select a dedicated network for live migration by using the OpenShift Container Platform web console.

Prerequisites

  • You configured a Multus network for live migration.

Procedure

  1. Navigate to Virtualization > Overview in the OpenShift Container Platform web console.
  2. Click the Settings tab and then click Live migration.
  3. Select the network from the Live migration network list.

8.11.3. Additional resources

8.12. Configuring and viewing IP addresses

You can configure an IP address when you create a virtual machine (VM). The IP address is provisioned with cloud-init.

You can view the IP address of a VM by using the OpenShift Container Platform web console or the command line. The network information is collected by the QEMU guest agent.

8.12.1. Configuring IP addresses for virtual machines

You can configure a static IP address when you create a virtual machine (VM) by using the web console or the command line.

You can configure a dynamic IP address when you create a VM by using the command line.

The IP address is provisioned with cloud-init.

8.12.1.1. Configuring an IP address when creating a virtual machine by using the command line

You can configure a static or dynamic IP address when you create a virtual machine (VM). The IP address is provisioned with cloud-init.

Note

If the VM is connected to the pod network, the pod network interface is the default route unless you update it.

Prerequisites

  • The virtual machine is connected to a secondary network.
  • You have a DHCP server available on the secondary network to configure a dynamic IP for the virtual machine.

Procedure

  • Edit the spec.template.spec.volumes.cloudInitNoCloud.networkData stanza of the virtual machine configuration:

    • To configure a dynamic IP address, specify the interface name and enable DHCP:

      kind: VirtualMachine
      spec:
      # ...
        template:
        # ...
          spec:
            volumes:
            - cloudInitNoCloud:
                networkData: |
                  version: 2
                  ethernets:
                    eth1: 1
                      dhcp4: true
      1
      Specify the interface name.
    • To configure a static IP, specify the interface name and the IP address:

      kind: VirtualMachine
      spec:
      # ...
        template:
        # ...
          spec:
            volumes:
            - cloudInitNoCloud:
                networkData: |
                  version: 2
                  ethernets:
                    eth1: 1
                      addresses:
                      - 10.10.10.14/24 2
      1
      Specify the interface name.
      2
      Specify the static IP address.

8.12.2. Viewing IP addresses of virtual machines

You can view the IP address of a VM by using the OpenShift Container Platform web console or the command line.

The network information is collected by the QEMU guest agent.

8.12.2.1. Viewing the IP address of a virtual machine by using the web console

You can view the IP address of a virtual machine (VM) by using the OpenShift Container Platform web console.

Note

You must install the QEMU guest agent on a VM to view the IP address of a secondary network interface. A pod network interface does not require the QEMU guest agent.

Procedure

  1. In the OpenShift Container Platform console, click VirtualizationVirtualMachines from the side menu.
  2. Select a VM to open the VirtualMachine details page.
  3. Click the Details tab to view the IP address.
8.12.2.2. Viewing the IP address of a virtual machine by using the command line

You can view the IP address of a virtual machine (VM) by using the command line.

Note

You must install the QEMU guest agent on a VM to view the IP address of a secondary network interface. A pod network interface does not require the QEMU guest agent.

Procedure

  • Obtain the virtual machine instance configuration by running the following command:

    $ oc describe vmi <vmi_name>

    Example output

    # ...
    Interfaces:
       Interface Name:  eth0
       Ip Address:      10.244.0.37/24
       Ip Addresses:
         10.244.0.37/24
         fe80::858:aff:fef4:25/64
       Mac:             0a:58:0a:f4:00:25
       Name:            default
       Interface Name:  v2
       Ip Address:      1.1.1.7/24
       Ip Addresses:
         1.1.1.7/24
         fe80::f4d9:70ff:fe13:9089/64
       Mac:             f6:d9:70:13:90:89
       Interface Name:  v1
       Ip Address:      1.1.1.1/24
       Ip Addresses:
         1.1.1.1/24
         1.1.1.2/24
         1.1.1.4/24
         2001:de7:0:f101::1/64
         2001:db8:0:f101::1/64
         fe80::1420:84ff:fe10:17aa/64
       Mac:             16:20:84:10:17:aa

8.12.3. Additional resources

8.13. Accessing a virtual machine by using its external FQDN

You can access a virtual machine (VM) that is attached to a secondary network interface from outside the cluster by using its fully qualified domain name (FQDN).

Important

Accessing a VM from outside the cluster by using its FQDN is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

8.13.1. Configuring a DNS server for secondary networks

The Cluster Network Addons Operator (CNAO) deploys a Domain Name Server (DNS) server and monitoring components when you enable the deployKubeSecondaryDNS feature gate in the HyperConverged custom resource (CR).

Prerequisites

  • You installed the OpenShift CLI (oc).
  • You configured a load balancer for the cluster.
  • You logged in to the cluster with cluster-admin permissions.

Procedure

  1. Edit the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Enable the DNS server and monitoring components according to the following example:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
        featureGates:
          deployKubeSecondaryDNS: true 1
    # ...
    1
    Enables the DNS server
  3. Save the file and exit the editor.
  4. Create a load balancer service to expose the DNS server outside the cluster by running the oc expose command according to the following example:

    $ oc expose -n openshift-cnv deployment/secondary-dns --name=dns-lb \
      --type=LoadBalancer --port=53 --target-port=5353 --protocol='UDP'
  5. Retrieve the external IP address by running the following command:

    $ oc get service -n openshift-cnv

    Example output

    NAME       TYPE             CLUSTER-IP     EXTERNAL-IP      PORT(S)          AGE
    dns-lb     LoadBalancer     172.30.27.5    10.46.41.94      53:31829/TCP     5s

  6. Edit the HyperConverged CR again:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  7. Add the external IP address that you previously retrieved to the kubeSecondaryDNSNameServerIP field in the enterprise DNS server records. For example:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      featureGates:
        deployKubeSecondaryDNS: true
      kubeSecondaryDNSNameServerIP: "10.46.41.94" 1
    # ...
    1
    Specify the external IP address exposed by the load balancer service.
  8. Save the file and exit the editor.
  9. Retrieve the cluster FQDN by running the following command:

     $ oc get dnses.config.openshift.io cluster -o jsonpath='{.spec.baseDomain}'

    Example output

    openshift.example.com

  10. Point to the DNS server. To do so, add the kubeSecondaryDNSNameServerIP value and the cluster FQDN to the enterprise DNS server records. For example:

    vm.<FQDN>. IN NS ns.vm.<FQDN>.
    ns.vm.<FQDN>. IN A <kubeSecondaryDNSNameServerIP>

8.13.2. Connecting to a VM on a secondary network by using the cluster FQDN

You can access a running virtual machine (VM) attached to a secondary network interface by using the fully qualified domain name (FQDN) of the cluster.

Prerequisites

  • You installed the QEMU guest agent on the VM.
  • The IP address of the VM is public.
  • You configured the DNS server for secondary networks.
  • You retrieved the fully qualified domain name (FQDN) of the cluster.

    To obtain the FQDN, use the oc get command as follows:

    $ oc get dnses.config.openshift.io cluster -o json | jq .spec.baseDomain

Procedure

  1. Retrieve the network interface name from the VM configuration by running the following command:

    $ oc get vm -n <namespace> <vm_name> -o yaml

    Example output

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
      namespace: example-namespace
    spec:
      running: true
      template:
        spec:
          domain:
            devices:
              interfaces:
                - bridge: {}
                  name: example-nic
    # ...
          networks:
          - multus:
              networkName: bridge-conf
            name: example-nic 1

    1
    Note the name of the network interface.
  2. Connect to the VM by using the ssh command:

    $ ssh <user_name>@<interface_name>.<vm_name>.<namespace>.vm.<cluster_fqdn>

8.13.3. Additional resources

8.14. Managing MAC address pools for network interfaces

The KubeMacPool component allocates MAC addresses for virtual machine (VM) network interfaces from a shared MAC address pool. This ensures that each network interface is assigned a unique MAC address.

A virtual machine instance created from that VM retains the assigned MAC address across reboots.

Note

KubeMacPool does not handle virtual machine instances created independently from a virtual machine.

8.14.1. Managing KubeMacPool by using the command line

You can disable and re-enable KubeMacPool by using the command line.

KubeMacPool is enabled by default.

Procedure

  • To disable KubeMacPool in two namespaces, run the following command:

    $ oc label namespace <namespace1> <namespace2> mutatevirtualmachines.kubemacpool.io=ignore
  • To re-enable KubeMacPool in two namespaces, run the following command:

    $ oc label namespace <namespace1> <namespace2> mutatevirtualmachines.kubemacpool.io-

Chapter 9. Storage

9.1. Storage configuration overview

You can configure a default storage class, storage profiles, Containerized Data Importer (CDI), data volumes, and automatic boot source updates.

9.1.1. Storage

The following storage configuration tasks are mandatory:

Configure a default storage class
You must configure a default storage class for your cluster. Otherwise, the cluster cannot receive automated boot source updates.
Configure storage profiles
You must configure storage profiles if your storage provider is not recognized by CDI. A storage profile provides recommended storage settings based on the associated storage class.

The following storage configuration tasks are optional:

Reserve additional PVC space for file system overhead
By default, 5.5% of a file system PVC is reserved for overhead, reducing the space available for VM disks by that amount. You can configure a different overhead value.
Configure local storage by using the hostpath provisioner
You can configure local storage for virtual machines by using the hostpath provisioner (HPP). When you install the OpenShift Virtualization Operator, the HPP Operator is automatically installed.
Configure user permissions to clone data volumes between namespaces
You can configure RBAC roles to enable users to clone data volumes between namespaces.

9.1.2. Containerized Data Importer

You can perform the following Containerized Data Importer (CDI) configuration tasks:

Override the resource request limits of a namespace
You can configure CDI to import, upload, and clone VM disks into namespaces that are subject to CPU and memory resource restrictions.
Configure CDI scratch space
CDI requires scratch space (temporary storage) to complete some operations, such as importing and uploading VM images. During this process, CDI provisions a scratch space PVC equal to the size of the PVC backing the destination data volume (DV).

9.1.3. Data volumes

You can perform the following data volume configuration tasks:

Enable preallocation for data volumes
CDI can preallocate disk space to improve write performance when creating data volumes. You can enable preallocation for specific data volumes.
Manage data volume annotations
Data volume annotations allow you to manage pod behavior. You can add one or more annotations to a data volume, which then propagates to the created importer pods.

9.1.4. Boot source updates

You can perform the following boot source update configuration task:

Manage automatic boot source updates
Boot sources can make virtual machine (VM) creation more accessible and efficient for users. If automatic boot source updates are enabled, CDI imports, polls, and updates the images so that they are ready to be cloned for new VMs. By default, CDI automatically updates Red Hat boot sources. You can enable automatic updates for custom boot sources.

9.2. Configuring storage profiles

A storage profile provides recommended storage settings based on the associated storage class. A storage profile is allocated for each storage class.

The Containerized Data Importer (CDI) recognizes a storage provider if it has been configured to identify and interact with the storage provider’s capabilities.

For recognized storage types, the CDI provides values that optimize the creation of PVCs. You can also configure automatic settings for the storage class by customizing the storage profile. If the CDI does not recognize your storage provider, you must configure storage profiles.

Important

When using OpenShift Virtualization with Red Hat OpenShift Data Foundation, specify RBD block mode persistent volume claims (PVCs) when creating virtual machine disks. RBD block mode volumes are more efficient and provide better performance than Ceph FS or RBD filesystem-mode PVCs.

To specify RBD block mode PVCs, use the 'ocs-storagecluster-ceph-rbd' storage class and VolumeMode: Block.

9.2.1. Customizing the storage profile

You can specify default parameters by editing the StorageProfile object for the provisioner’s storage class. These default parameters only apply to the persistent volume claim (PVC) if they are not configured in the DataVolume object.

You cannot modify storage class parameters. To make changes, delete and re-create the storage class. You must then reapply any customizations that were previously made to the storage profile.

An empty status section in a storage profile indicates that a storage provisioner is not recognized by the Containerized Data Interface (CDI). Customizing a storage profile is necessary if you have a storage provisioner that is not recognized by CDI. In this case, the administrator sets appropriate values in the storage profile to ensure successful allocations.

Warning

If you create a data volume and omit YAML attributes and these attributes are not defined in the storage profile, then the requested storage will not be allocated and the underlying persistent volume claim (PVC) will not be created.

Prerequisites

  • Ensure that your planned configuration is supported by the storage class and its provider. Specifying an incompatible configuration in a storage profile causes volume provisioning to fail.

Procedure

  1. Edit the storage profile. In this example, the provisioner is not recognized by CDI.

    $ oc edit storageprofile <storage_class>

    Example storage profile

    apiVersion: cdi.kubevirt.io/v1beta1
    kind: StorageProfile
    metadata:
      name: <unknown_provisioner_class>
    # ...
    spec: {}
    status:
      provisioner: <unknown_provisioner>
      storageClass: <unknown_provisioner_class>

  2. Provide the needed attribute values in the storage profile:

    Example storage profile

    apiVersion: cdi.kubevirt.io/v1beta1
    kind: StorageProfile
    metadata:
      name: <unknown_provisioner_class>
    # ...
    spec:
      claimPropertySets:
      - accessModes:
        - ReadWriteOnce 1
        volumeMode:
          Filesystem 2
    status:
      provisioner: <unknown_provisioner>
      storageClass: <unknown_provisioner_class>

    1
    The accessModes that you select.
    2
    The volumeMode that you select.

    After you save your changes, the selected values appear in the storage profile status element.

9.2.1.1. Setting a default cloning strategy using a storage profile

You can use storage profiles to set a default cloning method for a storage class, creating a cloning strategy. Setting cloning strategies can be helpful, for example, if your storage vendor only supports certain cloning methods. It also allows you to select a method that limits resource usage or maximizes performance.

Cloning strategies can be specified by setting the cloneStrategy attribute in a storage profile to one of these values:

  • snapshot is used by default when snapshots are configured. The CDI will use the snapshot method if it recognizes the storage provider and the provider supports Container Storage Interface (CSI) snapshots. This cloning strategy uses a temporary volume snapshot to clone the volume.
  • copy uses a source pod and a target pod to copy data from the source volume to the target volume. Host-assisted cloning is the least efficient method of cloning.
  • csi-clone uses the CSI clone API to efficiently clone an existing volume without using an interim volume snapshot. Unlike snapshot or copy, which are used by default if no storage profile is defined, CSI volume cloning is only used when you specify it in the StorageProfile object for the provisioner’s storage class.
Note

You can also set clone strategies using the CLI without modifying the default claimPropertySets in your YAML spec section.

Example storage profile

apiVersion: cdi.kubevirt.io/v1beta1
kind: StorageProfile
metadata:
  name: <provisioner_class>
# ...
spec:
  claimPropertySets:
  - accessModes:
    - ReadWriteOnce 1
    volumeMode:
      Filesystem 2
  cloneStrategy: csi-clone 3
status:
  provisioner: <provisioner>
  storageClass: <provisioner_class>

1
Specify the access mode.
2
Specify the volume mode.
3
Specify the default cloning strategy.
Table 9.1. Storage providers and default behaviors
Storage providerDefault behavior

rook-ceph.rbd.csi.ceph.com

Snapshot

openshift-storage.rbd.csi.ceph.com

Snapshot

csi-vxflexos.dellemc.com

CSI Clone

csi-isilon.dellemc.com

CSI Clone

csi-powermax.dellemc.com

CSI Clone

csi-powerstore.dellemc.com

CSI Clone

hspc.csi.hitachi.com

CSI Clone

csi.hpe.com

CSI Clone

spectrumscale.csi.ibm.com

CSI Clone

rook-ceph.rbd.csi.ceph.com

CSI Clone

openshift-storage.rbd.csi.ceph.com

CSI Clone

cephfs.csi.ceph.com

CSI Clone

openshift-storage.cephfs.csi.ceph.com

CSI Clone

9.3. Managing automatic boot source updates

You can manage automatic updates for the following boot sources:

Boot sources can make virtual machine (VM) creation more accessible and efficient for users. If automatic boot source updates are enabled, the Containerized Data Importer (CDI) imports, polls, and updates the images so that they are ready to be cloned for new VMs. By default, CDI automatically updates Red Hat boot sources.

9.3.1. Managing Red Hat boot source updates

You can opt out of automatic updates for all system-defined boot sources by disabling the enableCommonBootImageImport feature gate. If you disable this feature gate, all DataImportCron objects are deleted. This does not remove previously imported boot source objects that store operating system images, though administrators can delete them manually.

When the enableCommonBootImageImport feature gate is disabled, DataSource objects are reset so that they no longer point to the original boot source. An administrator can manually provide a boot source by creating a new persistent volume claim (PVC) or volume snapshot for the DataSource object, then populating it with an operating system image.

9.3.1.1. Managing automatic updates for all system-defined boot sources

Disabling automatic boot source imports and updates can lower resource usage. In disconnected environments, disabling automatic boot source updates prevents CDIDataImportCronOutdated alerts from filling up logs.

To disable automatic updates for all system-defined boot sources, turn off the enableCommonBootImageImport feature gate by setting the value to false. Setting this value to true re-enables the feature gate and turns automatic updates back on.

Note

Custom boot sources are not affected by this setting.

Procedure

  • Toggle the feature gate for automatic boot source updates by editing the HyperConverged custom resource (CR).

    • To disable automatic boot source updates, set the spec.featureGates.enableCommonBootImageImport field in the HyperConverged CR to false. For example:

      $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
        --type json -p '[{"op": "replace", "path": \
        "/spec/featureGates/enableCommonBootImageImport", \
        "value": false}]'
    • To re-enable automatic boot source updates, set the spec.featureGates.enableCommonBootImageImport field in the HyperConverged CR to true. For example:

      $ oc patch hyperconverged kubevirt-hyperconverged -n openshift-cnv \
        --type json -p '[{"op": "replace", "path": \
        "/spec/featureGates/enableCommonBootImageImport", \
        "value": true}]'

9.3.2. Managing custom boot source updates

Custom boot sources that are not provided by OpenShift Virtualization are not controlled by the feature gate. You must manage them individually by editing the HyperConverged custom resource (CR).

Important

You must configure a storage class. Otherwise, the cluster cannot receive automated updates for custom boot sources. See Defining a storage class for details.

9.3.2.1. Configuring a storage class for custom boot source updates

You can override the default storage class by editing the HyperConverged custom resource (CR).

Important

Boot sources are created from storage using the default storage class. If your cluster does not have a default storage class, you must define one before configuring automatic updates for custom boot sources.

Procedure

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Define a new storage class by entering a value in the storageClassName field:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      dataImportCronTemplates:
      - metadata:
          name: rhel8-image-cron
        spec:
          template:
            spec:
              storageClassName: <new_storage_class> 1
          schedule: "0 */12 * * *" 2
          managedDataSource: <data_source> 3
    # ...
    1
    Define the storage class.
    2
    Required: Schedule for the job specified in cron format.
    3
    Required: The data source to use.
    For the custom image to be detected as an available boot source, the value of the `spec.dataVolumeTemplates.spec.sourceRef.name` parameter in the VM template must match this value.
  3. Remove the storageclass.kubernetes.io/is-default-class annotation from the current default storage class.

    1. Retrieve the name of the current default storage class by running the following command:

      $ oc get storageclass

      Example output

      NAME                          PROVISIONER                      RECLAIMPOLICY  VOLUMEBINDINGMODE    ALLOWVOLUMEEXPANSION  AGE
      csi-manila-ceph               manila.csi.openstack.org         Delete         Immediate            false                 11d
      hostpath-csi-basic (default)  kubevirt.io.hostpath-provisioner Delete         WaitForFirstConsumer false                 11d 1

      1
      In this example, the current default storage class is named hostpath-csi-basic.
    2. Remove the annotation from the current default storage class by running the following command:

      $ oc patch storageclass <current_default_storage_class> -p '{"metadata": {"annotations":{"storageclass.kubernetes.io/is-default-class":"false"}}}' 1
      1
      Replace <current_default_storage_class> with the storageClassName value of the default storage class.
  4. Set the new storage class as the default by running the following command:

    $ oc patch storageclass <new_storage_class> -p '{"metadata":{"annotations":{"storageclass.kubernetes.io/is-default-class":"true"}}}' 1
    1
    Replace <new_storage_class> with the storageClassName value that you added to the HyperConverged CR.
9.3.2.2. Enabling automatic updates for custom boot sources

OpenShift Virtualization automatically updates system-defined boot sources by default, but does not automatically update custom boot sources. You must manually enable automatic updates by editing the HyperConverged custom resource (CR).

Prerequisites

  • The cluster has a default storage class.

Procedure

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Edit the HyperConverged CR, adding the appropriate template and boot source in the dataImportCronTemplates section. For example:

    Example custom resource

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      dataImportCronTemplates:
      - metadata:
          name: centos7-image-cron
          annotations:
            cdi.kubevirt.io/storage.bind.immediate.requested: "true" 1
          labels:
            instancetype.kubevirt.io/default-preference: centos.7
            instancetype.kubevirt.io/default-instancetype: u1.medium
        spec:
          schedule: "0 */12 * * *" 2
          template:
            spec:
              source:
                registry: 3
                  url: docker://quay.io/containerdisks/centos:7-2009
              storage:
                resources:
                  requests:
                    storage: 30Gi
          garbageCollect: Outdated
          managedDataSource: centos7 4

    1
    This annotation is required for storage classes with volumeBindingMode set to WaitForFirstConsumer.
    2
    Schedule for the job specified in cron format.
    3
    Use to create a data volume from a registry source. Use the default pod pullMethod and not node pullMethod, which is based on the node docker cache. The node docker cache is useful when a registry image is available via Container.Image, but the CDI importer is not authorized to access it.
    4
    For the custom image to be detected as an available boot source, the name of the image’s managedDataSource must match the name of the template’s DataSource, which is found under spec.dataVolumeTemplates.spec.sourceRef.name in the VM template YAML file.
  3. Save the file.
9.3.2.3. Enabling volume snapshot boot sources

Enable volume snapshot boot sources by setting the parameter in the StorageProfile associated with the storage class that stores operating system base images. Although DataImportCron was originally designed to maintain only PVC sources, VolumeSnapshot sources scale better than PVC sources for certain storage types.

Note

Use volume snapshots on a storage profile that is proven to scale better when cloning from a single snapshot.

Prerequisites

  • You must have access to a volume snapshot with the operating system image.
  • The storage must support snapshotting.

Procedure

  1. Open the storage profile object that corresponds to the storage class used to provision boot sources by running the following command:

    $ oc edit storageprofile <storage_class>
  2. Review the dataImportCronSourceFormat specification of the StorageProfile to confirm whether or not the VM is using PVC or volume snapshot by default.
  3. Edit the storage profile, if needed, by updating the dataImportCronSourceFormat specification to snapshot.

    Example storage profile

    apiVersion: cdi.kubevirt.io/v1beta1
    kind: StorageProfile
    metadata:
    # ...
    spec:
      dataImportCronSourceFormat: snapshot

Verification

  1. Open the storage profile object that corresponds to the storage class used to provision boot sources.

    $ oc get storageprofile <storage_class>  -oyaml
  2. Confirm that the dataImportCronSourceFormat specification of the StorageProfile is set to 'snapshot', and that any DataSource objects that the DataImportCron points to now reference volume snapshots.

You can now use these boot sources to create virtual machines.

9.3.3. Disabling automatic updates for a single boot source

You can disable automatic updates for an individual boot source, whether it is custom or system-defined, by editing the HyperConverged custom resource (CR).

Procedure

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Disable automatic updates for an individual boot source by editing the spec.dataImportCronTemplates field.

    Custom boot source
    • Remove the boot source from the spec.dataImportCronTemplates field. Automatic updates are disabled for custom boot sources by default.
    System-defined boot source
    1. Add the boot source to spec.dataImportCronTemplates.

      Note

      Automatic updates are enabled by default for system-defined boot sources, but these boot sources are not listed in the CR unless you add them.

    2. Set the value of the dataimportcrontemplate.kubevirt.io/enable annotation to 'false'.

      For example:

      apiVersion: hco.kubevirt.io/v1beta1
      kind: HyperConverged
      metadata:
        name: kubevirt-hyperconverged
      spec:
        dataImportCronTemplates:
        - metadata:
            annotations:
              dataimportcrontemplate.kubevirt.io/enable: 'false'
            name: rhel8-image-cron
      # ...
  3. Save the file.

9.3.4. Verifying the status of a boot source

You can determine if a boot source is system-defined or custom by viewing the HyperConverged custom resource (CR).

Procedure

  1. View the contents of the HyperConverged CR by running the following command:

    $ oc get hyperconverged kubevirt-hyperconverged -n openshift-cnv -o yaml

    Example output

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
    # ...
    status:
    # ...
      dataImportCronTemplates:
      - metadata:
          annotations:
            cdi.kubevirt.io/storage.bind.immediate.requested: "true"
          name: centos-7-image-cron
        spec:
          garbageCollect: Outdated
          managedDataSource: centos7
          schedule: 55 8/12 * * *
          template:
            metadata: {}
            spec:
              source:
                registry:
                  url: docker://quay.io/containerdisks/centos:7-2009
              storage:
                resources:
                  requests:
                    storage: 30Gi
            status: {}
        status:
          commonTemplate: true 1
    # ...
      - metadata:
          annotations:
            cdi.kubevirt.io/storage.bind.immediate.requested: "true"
          name: user-defined-dic
        spec:
          garbageCollect: Outdated
          managedDataSource: user-defined-centos-stream8
          schedule: 55 8/12 * * *
          template:
            metadata: {}
            spec:
              source:
                registry:
                  pullMethod: node
                  url: docker://quay.io/containerdisks/centos-stream:8
              storage:
                resources:
                  requests:
                    storage: 30Gi
            status: {}
        status: {} 2
    # ...

    1
    Indicates a system-defined boot source.
    2
    Indicates a custom boot source.
  2. Verify the status of the boot source by reviewing the status.dataImportCronTemplates.status field.

    • If the field contains commonTemplate: true, it is a system-defined boot source.
    • If the status.dataImportCronTemplates.status field has the value {}, it is a custom boot source.

9.4. Reserving PVC space for file system overhead

When you add a virtual machine disk to a persistent volume claim (PVC) that uses the Filesystem volume mode, you must ensure that there is enough space on the PVC for the VM disk and for file system overhead, such as metadata.

By default, OpenShift Virtualization reserves 5.5% of the PVC space for overhead, reducing the space available for virtual machine disks by that amount.

You can configure a different overhead value by editing the HCO object. You can change the value globally and you can specify values for specific storage classes.

9.4.1. Overriding the default file system overhead value

Change the amount of persistent volume claim (PVC) space that the OpenShift Virtualization reserves for file system overhead by editing the spec.filesystemOverhead attribute of the HCO object.

Prerequisites

  • Install the OpenShift CLI (oc).

Procedure

  1. Open the HCO object for editing by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Edit the spec.filesystemOverhead fields, populating them with your chosen values:

    # ...
    spec:
      filesystemOverhead:
        global: "<new_global_value>" 1
        storageClass:
          <storage_class_name>: "<new_value_for_this_storage_class>" 2
    1
    The default file system overhead percentage used for any storage classes that do not already have a set value. For example, global: "0.07" reserves 7% of the PVC for file system overhead.
    2
    The file system overhead percentage for the specified storage class. For example, mystorageclass: "0.04" changes the default overhead value for PVCs in the mystorageclass storage class to 4%.
  3. Save and exit the editor to update the HCO object.

Verification

  • View the CDIConfig status and verify your changes by running one of the following commands:

    To generally verify changes to CDIConfig:

    $ oc get cdiconfig -o yaml

    To view your specific changes to CDIConfig:

    $ oc get cdiconfig -o jsonpath='{.items..status.filesystemOverhead}'

9.5. Configuring local storage by using the hostpath provisioner

You can configure local storage for virtual machines by using the hostpath provisioner (HPP).

When you install the OpenShift Virtualization Operator, the Hostpath Provisioner Operator is automatically installed. HPP is a local storage provisioner designed for OpenShift Virtualization that is created by the Hostpath Provisioner Operator. To use HPP, you create an HPP custom resource (CR) with a basic storage pool.

9.5.1. Creating a hostpath provisioner with a basic storage pool

You configure a hostpath provisioner (HPP) with a basic storage pool by creating an HPP custom resource (CR) with a storagePools stanza. The storage pool specifies the name and path used by the CSI driver.

Important

Do not create storage pools in the same partition as the operating system. Otherwise, the operating system partition might become filled to capacity, which will impact performance or cause the node to become unstable or unusable.

Prerequisites

  • The directories specified in spec.storagePools.path must have read/write access.

Procedure

  1. Create an hpp_cr.yaml file with a storagePools stanza as in the following example:

    apiVersion: hostpathprovisioner.kubevirt.io/v1beta1
    kind: HostPathProvisioner
    metadata:
      name: hostpath-provisioner
    spec:
      imagePullPolicy: IfNotPresent
      storagePools: 1
      - name: any_name
        path: "/var/myvolumes" 2
    workload:
      nodeSelector:
        kubernetes.io/os: linux
    1
    The storagePools stanza is an array to which you can add multiple entries.
    2
    Specify the storage pool directories under this node path.
  2. Save the file and exit.
  3. Create the HPP by running the following command:

    $ oc create -f hpp_cr.yaml
9.5.1.1. About creating storage classes

When you create a storage class, you set parameters that affect the dynamic provisioning of persistent volumes (PVs) that belong to that storage class. You cannot update a StorageClass object’s parameters after you create it.

In order to use the hostpath provisioner (HPP) you must create an associated storage class for the CSI driver with the storagePools stanza.

Note

Virtual machines use data volumes that are based on local PVs. Local PVs are bound to specific nodes. While the disk image is prepared for consumption by the virtual machine, it is possible that the virtual machine cannot be scheduled to the node where the local storage PV was previously pinned.

To solve this problem, use the Kubernetes pod scheduler to bind the persistent volume claim (PVC) to a PV on the correct node. By using the StorageClass value with volumeBindingMode parameter set to WaitForFirstConsumer, the binding and provisioning of the PV is delayed until a pod is created using the PVC.

9.5.1.2. Creating a storage class for the CSI driver with the storagePools stanza

To use the hostpath provisioner (HPP) you must create an associated storage class for the Container Storage Interface (CSI) driver.

When you create a storage class, you set parameters that affect the dynamic provisioning of persistent volumes (PVs) that belong to that storage class. You cannot update a StorageClass object’s parameters after you create it.

Note

Virtual machines use data volumes that are based on local PVs. Local PVs are bound to specific nodes. While a disk image is prepared for consumption by the virtual machine, it is possible that the virtual machine cannot be scheduled to the node where the local storage PV was previously pinned.

To solve this problem, use the Kubernetes pod scheduler to bind the persistent volume claim (PVC) to a PV on the correct node. By using the StorageClass value with volumeBindingMode parameter set to WaitForFirstConsumer, the binding and provisioning of the PV is delayed until a pod is created using the PVC.

Procedure

  1. Create a storageclass_csi.yaml file to define the storage class:

    apiVersion: storage.k8s.io/v1
    kind: StorageClass
    metadata:
      name: hostpath-csi
    provisioner: kubevirt.io.hostpath-provisioner
    reclaimPolicy: Delete 1
    volumeBindingMode: WaitForFirstConsumer 2
    parameters:
      storagePool: my-storage-pool 3
    1
    The two possible reclaimPolicy values are Delete and Retain. If you do not specify a value, the default value is Delete.
    2
    The volumeBindingMode parameter determines when dynamic provisioning and volume binding occur. Specify WaitForFirstConsumer to delay the binding and provisioning of a persistent volume (PV) until after a pod that uses the persistent volume claim (PVC) is created. This ensures that the PV meets the pod’s scheduling requirements.
    3
    Specify the name of the storage pool defined in the HPP CR.
  2. Save the file and exit.
  3. Create the StorageClass object by running the following command:

    $ oc create -f storageclass_csi.yaml

9.5.2. About storage pools created with PVC templates

If you have a single, large persistent volume (PV), you can create a storage pool by defining a PVC template in the hostpath provisioner (HPP) custom resource (CR).

A storage pool created with a PVC template can contain multiple HPP volumes. Splitting a PV into smaller volumes provides greater flexibility for data allocation.

The PVC template is based on the spec stanza of the PersistentVolumeClaim object:

Example PersistentVolumeClaim object

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: iso-pvc
spec:
  volumeMode: Block 1
  storageClassName: my-storage-class
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi

1
This value is only required for block volume mode PVs.

You define a storage pool using a pvcTemplate specification in the HPP CR. The Operator creates a PVC from the pvcTemplate specification for each node containing the HPP CSI driver. The PVC created from the PVC template consumes the single large PV, allowing the HPP to create smaller dynamic volumes.

You can combine basic storage pools with storage pools created from PVC templates.

9.5.2.1. Creating a storage pool with a PVC template

You can create a storage pool for multiple hostpath provisioner (HPP) volumes by specifying a PVC template in the HPP custom resource (CR).

Important

Do not create storage pools in the same partition as the operating system. Otherwise, the operating system partition might become filled to capacity, which will impact performance or cause the node to become unstable or unusable.

Prerequisites

  • The directories specified in spec.storagePools.path must have read/write access.

Procedure

  1. Create an hpp_pvc_template_pool.yaml file for the HPP CR that specifies a persistent volume (PVC) template in the storagePools stanza according to the following example:

    apiVersion: hostpathprovisioner.kubevirt.io/v1beta1
    kind: HostPathProvisioner
    metadata:
      name: hostpath-provisioner
    spec:
      imagePullPolicy: IfNotPresent
      storagePools: 1
      - name: my-storage-pool
        path: "/var/myvolumes" 2
        pvcTemplate:
          volumeMode: Block 3
          storageClassName: my-storage-class 4
          accessModes:
          - ReadWriteOnce
          resources:
            requests:
              storage: 5Gi 5
      workload:
        nodeSelector:
          kubernetes.io/os: linux
    1
    The storagePools stanza is an array that can contain both basic and PVC template storage pools.
    2
    Specify the storage pool directories under this node path.
    3
    Optional: The volumeMode parameter can be either Block or Filesystem as long as it matches the provisioned volume format. If no value is specified, the default is Filesystem. If the volumeMode is Block, the mounting pod creates an XFS file system on the block volume before mounting it.
    4
    If the storageClassName parameter is omitted, the default storage class is used to create PVCs. If you omit storageClassName, ensure that the HPP storage class is not the default storage class.
    5
    You can specify statically or dynamically provisioned storage. In either case, ensure the requested storage size is appropriate for the volume you want to virtually divide or the PVC cannot be bound to the large PV. If the storage class you are using uses dynamically provisioned storage, pick an allocation size that matches the size of a typical request.
  2. Save the file and exit.
  3. Create the HPP with a storage pool by running the following command:

    $ oc create -f hpp_pvc_template_pool.yaml

9.6. Enabling user permissions to clone data volumes across namespaces

The isolating nature of namespaces means that users cannot by default clone resources between namespaces.

To enable a user to clone a virtual machine to another namespace, a user with the cluster-admin role must create a new cluster role. Bind this cluster role to a user to enable them to clone virtual machines to the destination namespace.

9.6.1. Creating RBAC resources for cloning data volumes

Create a new cluster role that enables permissions for all actions for the datavolumes resource.

Prerequisites

  • You must have cluster admin privileges.

Procedure

  1. Create a ClusterRole manifest:

    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRole
    metadata:
      name: <datavolume-cloner> 1
    rules:
    - apiGroups: ["cdi.kubevirt.io"]
      resources: ["datavolumes/source"]
      verbs: ["*"]
    1
    Unique name for the cluster role.
  2. Create the cluster role in the cluster:

    $ oc create -f <datavolume-cloner.yaml> 1
    1
    The file name of the ClusterRole manifest created in the previous step.
  3. Create a RoleBinding manifest that applies to both the source and destination namespaces and references the cluster role created in the previous step.

    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: <allow-clone-to-user> 1
      namespace: <Source namespace> 2
    subjects:
    - kind: ServiceAccount
      name: default
      namespace: <Destination namespace> 3
    roleRef:
      kind: ClusterRole
      name: datavolume-cloner 4
      apiGroup: rbac.authorization.k8s.io
    1
    Unique name for the role binding.
    2
    The namespace for the source data volume.
    3
    The namespace to which the data volume is cloned.
    4
    The name of the cluster role created in the previous step.
  4. Create the role binding in the cluster:

    $ oc create -f <datavolume-cloner.yaml> 1
    1
    The file name of the RoleBinding manifest created in the previous step.

9.7. Configuring CDI to override CPU and memory quotas

You can configure the Containerized Data Importer (CDI) to import, upload, and clone virtual machine disks into namespaces that are subject to CPU and memory resource restrictions.

9.7.1. About CPU and memory quotas in a namespace

A resource quota, defined by the ResourceQuota object, imposes restrictions on a namespace that limit the total amount of compute resources that can be consumed by resources within that namespace.

The HyperConverged custom resource (CR) defines the user configuration for the Containerized Data Importer (CDI). The CPU and memory request and limit values are set to a default value of 0. This ensures that pods created by CDI that do not specify compute resource requirements are given the default values and are allowed to run in a namespace that is restricted with a quota.

When the AutoResourceLimits feature gate is enabled, OpenShift Virtualization automatically manages CPU and memory limits. If a namespace has both CPU and memory quotas, the memory limit is set to double the base allocation and the CPU limit is one per vCPU.

9.7.2. Overriding CPU and memory defaults

Modify the default settings for CPU and memory requests and limits for your use case by adding the spec.resourceRequirements.storageWorkloads stanza to the HyperConverged custom resource (CR).

Prerequisites

  • Install the OpenShift CLI (oc).

Procedure

  1. Edit the HyperConverged CR by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Add the spec.resourceRequirements.storageWorkloads stanza to the CR, setting the values based on your use case. For example:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      resourceRequirements:
        storageWorkloads:
          limits:
            cpu: "500m"
            memory: "2Gi"
          requests:
            cpu: "250m"
            memory: "1Gi"
  3. Save and exit the editor to update the HyperConverged CR.

9.7.3. Additional resources

9.8. Preparing CDI scratch space

9.8.1. About scratch space

The Containerized Data Importer (CDI) requires scratch space (temporary storage) to complete some operations, such as importing and uploading virtual machine images. During this process, CDI provisions a scratch space PVC equal to the size of the PVC backing the destination data volume (DV). The scratch space PVC is deleted after the operation completes or aborts.

You can define the storage class that is used to bind the scratch space PVC in the spec.scratchSpaceStorageClass field of the HyperConverged custom resource.

If the defined storage class does not match a storage class in the cluster, then the default storage class defined for the cluster is used. If there is no default storage class defined in the cluster, the storage class used to provision the original DV or PVC is used.

Note

CDI requires requesting scratch space with a file volume mode, regardless of the PVC backing the origin data volume. If the origin PVC is backed by block volume mode, you must define a storage class capable of provisioning file volume mode PVCs.

Manual provisioning

If there are no storage classes, CDI uses any PVCs in the project that match the size requirements for the image. If there are no PVCs that match these requirements, the CDI import pod remains in a Pending state until an appropriate PVC is made available or until a timeout function kills the pod.

9.8.2. CDI operations that require scratch space

TypeReason

Registry imports

CDI must download the image to a scratch space and extract the layers to find the image file. The image file is then passed to QEMU-IMG for conversion to a raw disk.

Upload image

QEMU-IMG does not accept input from STDIN. Instead, the image to upload is saved in scratch space before it can be passed to QEMU-IMG for conversion.

HTTP imports of archived images

QEMU-IMG does not know how to handle the archive formats CDI supports. Instead, the image is unarchived and saved into scratch space before it is passed to QEMU-IMG.

HTTP imports of authenticated images

QEMU-IMG inadequately handles authentication. Instead, the image is saved to scratch space and authenticated before it is passed to QEMU-IMG.

HTTP imports of custom certificates

QEMU-IMG inadequately handles custom certificates of HTTPS endpoints. Instead, CDI downloads the image to scratch space before passing the file to QEMU-IMG.

9.8.3. Defining a storage class

You can define the storage class that the Containerized Data Importer (CDI) uses when allocating scratch space by adding the spec.scratchSpaceStorageClass field to the HyperConverged custom resource (CR).

Prerequisites

  • Install the OpenShift CLI (oc).

Procedure

  1. Edit the HyperConverged CR by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Add the spec.scratchSpaceStorageClass field to the CR, setting the value to the name of a storage class that exists in the cluster:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      scratchSpaceStorageClass: "<storage_class>" 1
    1
    If you do not specify a storage class, CDI uses the storage class of the persistent volume claim that is being populated.
  3. Save and exit your default editor to update the HyperConverged CR.

9.8.4. CDI supported operations matrix

This matrix shows the supported CDI operations for content types against endpoints, and which of these operations requires scratch space.

Content typesHTTPHTTPSHTTP basic authRegistryUpload

KubeVirt (QCOW2)

✓ QCOW2
✓ GZ*
✓ XZ*

✓ QCOW2**
✓ GZ*
✓ XZ*

✓ QCOW2
✓ GZ*
✓ XZ*

✓ QCOW2*
□ GZ
□ XZ

✓ QCOW2*
✓ GZ*
✓ XZ*

KubeVirt (RAW)

✓ RAW
✓ GZ
✓ XZ

✓ RAW
✓ GZ
✓ XZ

✓ RAW
✓ GZ
✓ XZ

✓ RAW*
□ GZ
□ XZ

✓ RAW*
✓ GZ*
✓ XZ*

✓ Supported operation

□ Unsupported operation

* Requires scratch space

** Requires scratch space if a custom certificate authority is required

9.8.5. Additional resources

9.9. Using preallocation for data volumes

The Containerized Data Importer can preallocate disk space to improve write performance when creating data volumes.

You can enable preallocation for specific data volumes.

9.9.1. About preallocation

The Containerized Data Importer (CDI) can use the QEMU preallocate mode for data volumes to improve write performance. You can use preallocation mode for importing and uploading operations and when creating blank data volumes.

If preallocation is enabled, CDI uses the better preallocation method depending on the underlying file system and device type:

fallocate
If the file system supports it, CDI uses the operating system’s fallocate call to preallocate space by using the posix_fallocate function, which allocates blocks and marks them as uninitialized.
full
If fallocate mode cannot be used, full mode allocates space for the image by writing data to the underlying storage. Depending on the storage location, all the empty allocated space might be zeroed.

9.9.2. Enabling preallocation for a data volume

You can enable preallocation for specific data volumes by including the spec.preallocation field in the data volume manifest. You can enable preallocation mode in either the web console or by using the OpenShift CLI (oc).

Preallocation mode is supported for all CDI source types.

Procedure

  • Specify the spec.preallocation field in the data volume manifest:

    apiVersion: cdi.kubevirt.io/v1beta1
    kind: DataVolume
    metadata:
      name: preallocated-datavolume
    spec:
      source: 1
        registry:
          url: <image_url> 2
      storage:
        resources:
          requests:
            storage: 1Gi
      preallocation: true
    # ...
    1
    All CDI source types support preallocation. However, preallocation is ignored for cloning operations.
    2
    Specify the URL of the data source in your registry.

9.10. Managing data volume annotations

Data volume (DV) annotations allow you to manage pod behavior. You can add one or more annotations to a data volume, which then propagates to the created importer pods.

9.10.1. Example: Data volume annotations

This example shows how you can configure data volume (DV) annotations to control which network the importer pod uses. The v1.multus-cni.io/default-network: bridge-network annotation causes the pod to use the multus network named bridge-network as its default network. If you want the importer pod to use both the default network from the cluster and the secondary multus network, use the k8s.v1.cni.cncf.io/networks: <network_name> annotation.

Multus network annotation example

apiVersion: cdi.kubevirt.io/v1beta1
kind: DataVolume
metadata:
  name: datavolume-example
  annotations:
    v1.multus-cni.io/default-network: bridge-network 1
# ...

1
Multus network annotation

Chapter 10. Live migration

10.1. About live migration

Live migration is the process of moving a running virtual machine (VM) to another node in the cluster without interrupting the virtual workload. Live migration enables smooth transitions during cluster upgrades or any time a node needs to be drained for maintenance or configuration changes.

By default, live migration traffic is encrypted using Transport Layer Security (TLS).

10.1.1. Live migration requirements

Live migration has the following requirements:

  • The cluster must have shared storage with ReadWriteMany (RWX) access mode.
  • The cluster must have sufficient RAM and network bandwidth.

    Note

    You must ensure that there is enough memory request capacity in the cluster to support node drains that result in live migrations. You can determine the approximate required spare memory by using the following calculation:

    Product of (Maximum number of nodes that can drain in parallel) and (Highest total VM memory request allocations across nodes)

    The default number of migrations that can run in parallel in the cluster is 5.

  • If a VM uses a host model CPU, the nodes must support the CPU.
  • Configuring a dedicated Multus network for live migration is highly recommended. A dedicated network minimizes the effects of network saturation on tenant workloads during migration.

10.1.2. VM migration tuning

You can adjust your cluster-wide live migration settings based on the type of workload and migration scenario. This enables you to control how many VMs migrate at the same time, the network bandwidth you want to use for each migration, and how long OpenShift Virtualization attempts to complete the migration before canceling the process. Configure these settings in the HyperConverged custom resource (CR).

If you are migrating multiple VMs per node at the same time, set a bandwidthPerMigration limit to prevent a large or busy VM from using a large portion of the node’s network bandwidth. By default, the bandwidthPerMigration value is 0, which means unlimited.

A large VM running a heavy workload (for example, database processing), with higher memory dirty rates, requires a higher bandwidth to complete the migration.

Note

Post copy mode, when enabled, triggers if the initial pre-copy phase does not complete within the defined timeout. During post copy, the VM CPUs pause on the source host while transferring the minimum required memory pages. Then the VM CPUs activate on the destination host, and the remaining memory pages transfer into the destination node at runtime. This can impact performance during the transfer.

Post copy mode should not be used for critical data, or with unstable networks.

10.1.3. Common live migration tasks

You can perform the following live migration tasks:

10.1.4. Additional resources

10.2. Configuring live migration

You can configure live migration settings to ensure that the migration processes do not overwhelm the cluster.

You can configure live migration policies to apply different migration configurations to groups of virtual machines (VMs).

10.2.1. Configuring live migration limits and timeouts

Configure live migration limits and timeouts for the cluster by updating the HyperConverged custom resource (CR), which is located in the openshift-cnv namespace.

Procedure

  • Edit the HyperConverged CR and add the necessary live migration parameters:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

    Example configuration file

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      liveMigrationConfig:
        bandwidthPerMigration: 64Mi 1
        completionTimeoutPerGiB: 800 2
        parallelMigrationsPerCluster: 5 3
        parallelOutboundMigrationsPerNode: 2 4
        progressTimeout: 150 5
        allowPostCopy: false 6

    1
    Bandwidth limit of each migration, where the value is the quantity of bytes per second. For example, a value of 2048Mi means 2048 MiB/s. Default: 0, which is unlimited.
    2
    The migration is canceled if it has not completed in this time, in seconds per GiB of memory. For example, a VM with 6GiB memory times out if it has not completed migration in 4800 seconds. If the Migration Method is BlockMigration, the size of the migrating disks is included in the calculation.
    3
    Number of migrations running in parallel in the cluster. Default: 5.
    4
    Maximum number of outbound migrations per node. Default: 2.
    5
    The migration is canceled if memory copy fails to make progress in this time, in seconds. Default: 150.
    6
    If a VM is running a heavy workload and the memory dirty rate is too high, this can prevent the migration from one node to another from converging. To prevent this, you can enable post copy mode. By default, allowPostCopy is set to false.
Note

You can restore the default value for any spec.liveMigrationConfig field by deleting that key/value pair and saving the file. For example, delete progressTimeout: <value> to restore the default progressTimeout: 150.

10.2.2. Configure live migration for heavy workloads

When migrating a VM running a heavy workload (for example, database processing) with higher memory dirty rates, you need a higher bandwidth to complete the migration.

If the dirty rate is too high, the migration from one node to another does not converge. To prevent this, enable post copy mode.

Post copy mode triggers if the initial pre-copy phase does not complete within the defined timeout. During post copy, the VM CPUs pause on the source host while transferring the minimum required memory pages. Then the VM CPUs activate on the destination host, and the remaining memory pages transfer into the destination node at runtime.

Configure live migration for heavy workloads by updating the HyperConverged custom resource (CR), which is located in the openshift-cnv namespace.

Procedure

  1. Edit the HyperConverged CR and add the necessary parameters for migrating heavy workloads:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv

    Example configuration file

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      liveMigrationConfig:
        bandwidthPerMigration: 0Mi 1
        completionTimeoutPerGiB: 150 2
        parallelMigrationsPerCluster: 5 3
        parallelOutboundMigrationsPerNode: 1 4
        progressTimeout: 150 5
        allowPostCopy: true 6

    1
    Bandwidth limit of each migration, where the value is the quantity of bytes per second. The default is 0, which is unlimited.
    2
    The migration is canceled if it is not completed in this time, and triggers post copy mode, when post copy is enabled. This value is measured in seconds per GiB of memory. You can lower completionTimeoutPerGiB to trigger post copy mode earlier in the migration process, or raise the completionTimeoutPerGiB to trigger post copy mode later in the migration process.
    3
    Number of migrations running in parallel in the cluster. The default is 5. Keeping the parallelMigrationsPerCluster setting low is better when migrating heavy workloads.
    4
    Maximum number of outbound migrations per node. Configure a single VM per node for heavy workloads.
    5
    The migration is canceled if memory copy fails to make progress in this time. This value is measured in seconds. Increase this parameter for large memory sizes running heavy workloads.
    6
    Use post copy mode when memory dirty rates are high to ensure the migration converges. Set allowPostCopy to true to enable post copy mode.
  2. Optional: If your main network is too busy for the migration, configure a secondary, dedicated migration network.
Note

Post copy mode can impact performance during the transfer, and should not be used for critical data, or with unstable networks.

10.2.3. Additional resources

10.2.4. Live migration policies

You can create live migration policies to apply different migration configurations to groups of VMs that are defined by VM or project labels.

Tip

You can create live migration policies by using the OpenShift Virtualization web console.

10.2.4.1. Creating a live migration policy by using the command line

You can create a live migration policy by using the command line. KubeVirt applies the live migration policy to selected virtual machines (VMs) by using any combination of labels:

  • VM labels such as size, os, or gpu
  • Project labels such as priority, bandwidth, or hpc-workload

For the policy to apply to a specific group of VMs, all labels on the group of VMs must match the labels of the policy.

Note

If multiple live migration policies apply to a VM, the policy with the greatest number of matching labels takes precedence.

If multiple policies meet this criteria, the policies are sorted by alphabetical order of the matching label keys, and the first one in that order takes precedence.

Procedure

  1. Edit the VM object to which you want to apply a live migration policy, and add the corresponding VM labels.

    1. Open the YAML configuration of the resource:

      $ oc edit vm <vm_name>
    2. Adjust the required label values in the .spec.template.metadata.labels section of the configuration. For example, to mark the VM as a production VM for the purposes of migration policies, add the kubevirt.io/environment: production line:

      apiVersion: migrations.kubevirt.io/v1alpha1
      kind: VirtualMachine
      metadata:
        name: <vm_name>
        namespace: default
        labels:
          app: my-app
          environment: production
      spec:
        template:
          metadata:
            labels:
              kubevirt.io/domain: <vm_name>
              kubevirt.io/size: large
              kubevirt.io/environment: production
      # ...
    3. Save and exit the configuration.
  2. Configure a MigrationPolicy object with the corresponding labels. The following example configures a policy that applies to all VMs that are labeled as production:

    apiVersion: migrations.kubevirt.io/v1alpha1
    kind: MigrationPolicy
    metadata:
      name: <migration_policy>
    spec:
      selectors:
        namespaceSelector: 1
          hpc-workloads: "True"
          xyz-workloads-type: ""
        virtualMachineInstanceSelector: 2
          kubevirt.io/environment: "production"
    1
    Specify project labels.
    2
    Specify VM labels.
  3. Create the migration policy by running the following command:

    $ oc create migrationpolicy -f <migration_policy>.yaml

10.2.5. Additional resources

10.3. Initiating and canceling live migration

You can initiate the live migration of a virtual machine (VM) to another node by using the OpenShift Container Platform web console or the command line.

You can cancel a live migration by using the web console or the command line. The VM remains on its original node.

Tip

You can also initiate and cancel live migration by using the virtctl migrate <vm_name> and virtctl migrate-cancel <vm_name> commands.

10.3.1. Initiating live migration

10.3.1.1. Initiating live migration by using the web console

You can live migrate a running virtual machine (VM) to a different node in the cluster by using the OpenShift Container Platform web console.

Note

The Migrate action is visible to all users but only cluster administrators can initiate a live migration.

Prerequisites

  • The VM must be migratable.
  • If the VM is configured with a host model CPU, the cluster must have an available node that supports the CPU model.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select Migrate from the Options menu kebab beside a VM.
  3. Click Migrate.
10.3.1.2. Initiating live migration by using the command line

You can initiate the live migration of a running virtual machine (VM) by using the command line to create a VirtualMachineInstanceMigration object for the VM.

Procedure

  1. Create a VirtualMachineInstanceMigration manifest for the VM that you want to migrate:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachineInstanceMigration
    metadata:
      name: <migration_name>
    spec:
      vmiName: <vm_name>
  2. Create the object by running the following command:

    $ oc create -f <migration_name>.yaml

    The VirtualMachineInstanceMigration object triggers a live migration of the VM. This object exists in the cluster for as long as the virtual machine instance is running, unless manually deleted.

Verification

  • Obtain the VM status by running the following command:

    $ oc describe vmi <vm_name> -n <namespace>

    Example output

    # ...
    Status:
      Conditions:
        Last Probe Time:       <nil>
        Last Transition Time:  <nil>
        Status:                True
        Type:                  LiveMigratable
      Migration Method:  LiveMigration
      Migration State:
        Completed:                    true
        End Timestamp:                2018-12-24T06:19:42Z
        Migration UID:                d78c8962-0743-11e9-a540-fa163e0c69f1
        Source Node:                  node2.example.com
        Start Timestamp:              2018-12-24T06:19:35Z
        Target Node:                  node1.example.com
        Target Node Address:          10.9.0.18:43891
        Target Node Domain Detected:  true

10.3.2. Canceling live migration

10.3.2.1. Canceling live migration by using the web console

You can cancel the live migration of a virtual machine (VM) by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select Cancel Migration on the Options menu kebab beside a VM.
10.3.2.2. Canceling live migration by using the command line

Cancel the live migration of a virtual machine by deleting the VirtualMachineInstanceMigration object associated with the migration.

Procedure

  • Delete the VirtualMachineInstanceMigration object that triggered the live migration, migration-job in this example:

    $ oc delete vmim migration-job

Chapter 11. Nodes

11.1. Node maintenance

Nodes can be placed into maintenance mode by using the oc adm utility or NodeMaintenance custom resources (CRs).

Note

The node-maintenance-operator (NMO) is no longer shipped with OpenShift Virtualization. It is deployed as a standalone Operator from the OperatorHub in the OpenShift Container Platform web console or by using the OpenShift CLI (oc).

For more information on remediation, fencing, and maintaining nodes, see the Workload Availability for Red Hat OpenShift documentation.

Important

Virtual machines (VMs) must have a persistent volume claim (PVC) with a shared ReadWriteMany (RWX) access mode to be live migrated.

The Node Maintenance Operator watches for new or deleted NodeMaintenance CRs. When a new NodeMaintenance CR is detected, no new workloads are scheduled and the node is cordoned off from the rest of the cluster. All pods that can be evicted are evicted from the node. When a NodeMaintenance CR is deleted, the node that is referenced in the CR is made available for new workloads.

Note

Using a NodeMaintenance CR for node maintenance tasks achieves the same results as the oc adm cordon and oc adm drain commands using standard OpenShift Container Platform custom resource processing.

11.1.1. Eviction strategies

Placing a node into maintenance marks the node as unschedulable and drains all the VMs and pods from it.

You can configure eviction strategies for virtual machines (VMs) or for the cluster.

VM eviction strategy

The VM LiveMigrate eviction strategy ensures that a virtual machine instance (VMI) is not interrupted if the node is placed into maintenance or drained. VMIs with this eviction strategy will be live migrated to another node.

You can configure eviction strategies for virtual machines (VMs) by using the OpenShift Virtualization web console or the command line.

Important

The default eviction strategy is LiveMigrate. A non-migratable VM with a LiveMigrate eviction strategy might prevent nodes from draining or block an infrastructure upgrade because the VM is not evicted from the node. This situation causes a migration to remain in a Pending or Scheduling state unless you shut down the VM manually.

You must set the eviction strategy of non-migratable VMs to LiveMigrateIfPossible, which does not block an upgrade, or to None, for VMs that should not be migrated.

Cluster eviction strategy
You can configure an eviction strategy for the cluster to prioritize workload continuity or infrastructure upgrade.
Table 11.1. Cluster eviction strategies
Eviction strategyDescriptionInterrupts workflowBlocks upgrades

LiveMigrate 1

Prioritizes workload continuity over upgrades.

No

Yes 2

LiveMigrateIfPossible

Prioritizes upgrades over workload continuity to ensure that the environment is updated.

Yes

No

None 3

Shuts down VMs with no eviction strategy.

Yes

No

  1. Default eviction strategy for multi-node clusters.
  2. If a VM blocks an upgrade, you must shut down the VM manually.
  3. Default eviction strategy for single-node OpenShift.
11.1.1.1. Configuring a VM eviction strategy using the command line

You can configure an eviction strategy for a virtual machine (VM) by using the command line.

Important

The default eviction strategy is LiveMigrate. A non-migratable VM with a LiveMigrate eviction strategy might prevent nodes from draining or block an infrastructure upgrade because the VM is not evicted from the node. This situation causes a migration to remain in a Pending or Scheduling state unless you shut down the VM manually.

You must set the eviction strategy of non-migratable VMs to LiveMigrateIfPossible, which does not block an upgrade, or to None, for VMs that should not be migrated.

Procedure

  1. Edit the VirtualMachine resource by running the following command:

    $ oc edit vm <vm_name> -n <namespace>

    Example eviction strategy

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: <vm_name>
    spec:
      template:
        spec:
          evictionStrategy: LiveMigrateIfPossible 1
    # ...

    1
    Specify the eviction strategy. The default value is LiveMigrate.
  2. Restart the VM to apply the changes:

    $ virtctl restart <vm_name> -n <namespace>
11.1.1.2. Configuring a cluster eviction strategy by using the command line

You can configure an eviction strategy for a cluster by using the command line.

Procedure

  1. Edit the hyperconverged resource by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Set the cluster eviction strategy as shown in the following example:

    Example cluster eviction strategy

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      evictionStrategy: LiveMigrate
    # ...

11.1.2. Run strategies

A virtual machine (VM) configured with spec.running: true is immediately restarted. The spec.runStrategy key provides greater flexibility for determining how a VM behaves under certain conditions.

Important

The spec.runStrategy and spec.running keys are mutually exclusive. Only one of them can be used.

A VM configuration with both keys is invalid.

11.1.2.1. Run strategies

The spec.runStrategy key has four possible values:

Always
The virtual machine instance (VMI) is always present when a virtual machine (VM) is created on another node. A new VMI is created if the original stops for any reason. This is the same behavior as running: true.
RerunOnFailure
The VMI is re-created on another node if the previous instance fails. The instance is not re-created if the VM stops successfully, such as when it is shut down.
Manual
You control the VMI state manually with the start, stop, and restart virtctl client commands. The VM is not automatically restarted.
Halted
No VMI is present when a VM is created. This is the same behavior as running: false.

Different combinations of the virtctl start, stop and restart commands affect the run strategy.

The following table describes a VM’s transition between states. The first column shows the VM’s initial run strategy. The remaining columns show a virtctl command and the new run strategy after that command is run.

Table 11.2. Run strategy before and after virtctl commands
Initial run strategyStartStopRestart

Always

-

Halted

Always

RerunOnFailure

-

Halted

RerunOnFailure

Manual

Manual

Manual

Manual

Halted

Always

-

-

Note

If a node in a cluster installed by using installer-provisioned infrastructure fails the machine health check and is unavailable, VMs with runStrategy: Always or runStrategy: RerunOnFailure are rescheduled on a new node.

11.1.2.2. Configuring a VM run strategy by using the command line

You can configure a run strategy for a virtual machine (VM) by using the command line.

Important

The spec.runStrategy and spec.running keys are mutually exclusive. A VM configuration that contains values for both keys is invalid.

Procedure

  • Edit the VirtualMachine resource by running the following command:

    $ oc edit vm <vm_name> -n <namespace>

    Example run strategy

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    spec:
      runStrategy: Always
    # ...

11.1.3. Maintaining bare metal nodes

When you deploy OpenShift Container Platform on bare metal infrastructure, there are additional considerations that must be taken into account compared to deploying on cloud infrastructure. Unlike in cloud environments where the cluster nodes are considered ephemeral, re-provisioning a bare metal node requires significantly more time and effort for maintenance tasks.

When a bare metal node fails, for example, if a fatal kernel error happens or a NIC card hardware failure occurs, workloads on the failed node need to be restarted elsewhere else on the cluster while the problem node is repaired or replaced. Node maintenance mode allows cluster administrators to gracefully power down nodes, moving workloads to other parts of the cluster and ensuring workloads do not get interrupted. Detailed progress and node status details are provided during maintenance.

11.1.4. Additional resources

11.2. Managing node labeling for obsolete CPU models

You can schedule a virtual machine (VM) on a node as long as the VM CPU model and policy are supported by the node.

11.2.1. About node labeling for obsolete CPU models

The OpenShift Virtualization Operator uses a predefined list of obsolete CPU models to ensure that a node supports only valid CPU models for scheduled VMs.

By default, the following CPU models are eliminated from the list of labels generated for the node:

Example 11.1. Obsolete CPU models

"486"
Conroe
athlon
core2duo
coreduo
kvm32
kvm64
n270
pentium
pentium2
pentium3
pentiumpro
phenom
qemu32
qemu64

This predefined list is not visible in the HyperConverged CR. You cannot remove CPU models from this list, but you can add to the list by editing the spec.obsoleteCPUs.cpuModels field of the HyperConverged CR.

11.2.2. About node labeling for CPU features

Through the process of iteration, the base CPU features in the minimum CPU model are eliminated from the list of labels generated for the node.

For example:

  • An environment might have two supported CPU models: Penryn and Haswell.
  • If Penryn is specified as the CPU model for minCPU, each base CPU feature for Penryn is compared to the list of CPU features supported by Haswell.

    Example 11.2. CPU features supported by Penryn

    apic
    clflush
    cmov
    cx16
    cx8
    de
    fpu
    fxsr
    lahf_lm
    lm
    mca
    mce
    mmx
    msr
    mtrr
    nx
    pae
    pat
    pge
    pni
    pse
    pse36
    sep
    sse
    sse2
    sse4.1
    ssse3
    syscall
    tsc

    Example 11.3. CPU features supported by Haswell

    aes
    apic
    avx
    avx2
    bmi1
    bmi2
    clflush
    cmov
    cx16
    cx8
    de
    erms
    fma
    fpu
    fsgsbase
    fxsr
    hle
    invpcid
    lahf_lm
    lm
    mca
    mce
    mmx
    movbe
    msr
    mtrr
    nx
    pae
    pat
    pcid
    pclmuldq
    pge
    pni
    popcnt
    pse
    pse36
    rdtscp
    rtm
    sep
    smep
    sse
    sse2
    sse4.1
    sse4.2
    ssse3
    syscall
    tsc
    tsc-deadline
    x2apic
    xsave
  • If both Penryn and Haswell support a specific CPU feature, a label is not created for that feature. Labels are generated for CPU features that are supported only by Haswell and not by Penryn.

    Example 11.4. Node labels created for CPU features after iteration

    aes
    avx
    avx2
    bmi1
    bmi2
    erms
    fma
    fsgsbase
    hle
    invpcid
    movbe
    pcid
    pclmuldq
    popcnt
    rdtscp
    rtm
    sse4.2
    tsc-deadline
    x2apic
    xsave

11.2.3. Configuring obsolete CPU models

You can configure a list of obsolete CPU models by editing the HyperConverged custom resource (CR).

Procedure

  • Edit the HyperConverged custom resource, specifying the obsolete CPU models in the obsoleteCPUs array. For example:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
      namespace: openshift-cnv
    spec:
      obsoleteCPUs:
        cpuModels: 1
          - "<obsolete_cpu_1>"
          - "<obsolete_cpu_2>"
        minCPUModel: "<minimum_cpu_model>" 2
    1
    Replace the example values in the cpuModels array with obsolete CPU models. Any value that you specify is added to a predefined list of obsolete CPU models. The predefined list is not visible in the CR.
    2
    Replace this value with the minimum CPU model that you want to use for basic CPU features. If you do not specify a value, Penryn is used by default.

11.3. Preventing node reconciliation

Use skip-node annotation to prevent the node-labeller from reconciling a node.

11.3.1. Using skip-node annotation

If you want the node-labeller to skip a node, annotate that node by using the oc CLI.

Prerequisites

  • You have installed the OpenShift CLI (oc).

Procedure

  • Annotate the node that you want to skip by running the following command:

    $ oc annotate node <node_name> node-labeller.kubevirt.io/skip-node=true 1
    1
    Replace <node_name> with the name of the relevant node to skip.

    Reconciliation resumes on the next cycle after the node annotation is removed or set to false.

11.3.2. Additional resources

11.4. Deleting a failed node to trigger virtual machine failover

If a node fails and node health checks are not deployed on your cluster, virtual machines (VMs) with runStrategy: Always configured are not automatically relocated to healthy nodes.

11.4.1. Prerequisites

  • A node where a virtual machine was running has the NotReady condition.
  • The virtual machine that was running on the failed node has runStrategy set to Always.
  • You have installed the OpenShift CLI (oc).

11.4.2. Deleting nodes from a bare metal cluster

When you delete a node using the CLI, the node object is deleted in Kubernetes, but the pods that exist on the node are not deleted. Any bare pods not backed by a replication controller become inaccessible to OpenShift Container Platform. Pods backed by replication controllers are rescheduled to other available nodes. You must delete local manifest pods.

Procedure

Delete a node from an OpenShift Container Platform cluster running on bare metal by completing the following steps:

  1. Mark the node as unschedulable:

    $ oc adm cordon <node_name>
  2. Drain all pods on the node:

    $ oc adm drain <node_name> --force=true

    This step might fail if the node is offline or unresponsive. Even if the node does not respond, it might still be running a workload that writes to shared storage. To avoid data corruption, power down the physical hardware before you proceed.

  3. Delete the node from the cluster:

    $ oc delete node <node_name>

    Although the node object is now deleted from the cluster, it can still rejoin the cluster after reboot or if the kubelet service is restarted. To permanently delete the node and all its data, you must decommission the node.

  4. If you powered down the physical hardware, turn it back on so that the node can rejoin the cluster.

11.4.3. Verifying virtual machine failover

After all resources are terminated on the unhealthy node, a new virtual machine instance (VMI) is automatically created on a healthy node for each relocated VM. To confirm that the VMI was created, view all VMIs by using the oc CLI.

11.4.3.1. Listing all virtual machine instances using the CLI

You can list all virtual machine instances (VMIs) in your cluster, including standalone VMIs and those owned by virtual machines, by using the oc command-line interface (CLI).

Procedure

  • List all VMIs by running the following command:

    $ oc get vmis -A

Chapter 12. Monitoring

12.1. Monitoring overview

You can monitor the health of your cluster and virtual machines (VMs) with the following tools:

Monitoring OpenShift Virtualization VM health status
View the overall health of your OpenShift Virtualization environment in the web console by navigating to the HomeOverview page in the OpenShift Container Platform web console. The Status card displays the overall health of OpenShift Virtualization based on the alerts and conditions.
OpenShift Container Platform cluster checkup framework

Run automated tests on your cluster with the OpenShift Container Platform cluster checkup framework to check the following conditions:

  • Network connectivity and latency between two VMs attached to a secondary network interface
  • VM running a Data Plane Development Kit (DPDK) workload with zero packet loss
  • Cluster storage is optimally configured for OpenShift Virtualization
Prometheus queries for virtual resources
Query vCPU, network, storage, and guest memory swapping usage and live migration progress.
VM custom metrics
Configure the node-exporter service to expose internal VM metrics and processes.
VM health checks
Configure readiness, liveness, and guest agent ping probes and a watchdog for VMs.
Runbooks
Diagnose and resolve issues that trigger OpenShift Virtualization alerts in the OpenShift Container Platform web console.

12.2. OpenShift Virtualization cluster checkup framework

OpenShift Virtualization includes the following predefined checkups that can be used for cluster maintenance and troubleshooting:

  • Latency checkup, which verifies network connectivity and measures latency between two virtual machines (VMs) that are attached to a secondary network interface.

    Important

    Before you run a latency checkup, you must first create a bridge interface on the cluster nodes to connect the VM’s secondary interface to any interface on the node. If you do not create a bridge interface, the VMs do not start and the job fails.

  • Storage checkup, which verifies if the cluster storage is optimally configured for OpenShift Virtualization.
  • DPDK checkup, which verifies that a node can run a VM with a Data Plane Development Kit (DPDK) workload with zero packet loss.
Important

The OpenShift Virtualization cluster checkup framework is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

12.2.1. About the OpenShift Virtualization cluster checkup framework

A checkup is an automated test workload that allows you to verify if a specific cluster functionality works as expected. The cluster checkup framework uses native Kubernetes resources to configure and execute the checkup.

By using predefined checkups, cluster administrators and developers can improve cluster maintainability, troubleshoot unexpected behavior, minimize errors, and save time. They can also review the results of the checkup and share them with experts for further analysis. Vendors can write and publish checkups for features or services that they provide and verify that their customer environments are configured correctly.

Running a predefined checkup in an existing namespace involves setting up a service account for the checkup, creating the Role and RoleBinding objects for the service account, enabling permissions for the checkup, and creating the input config map and the checkup job. You can run a checkup multiple times.

Important

You must always:

  • Verify that the checkup image is from a trustworthy source before applying it.
  • Review the checkup permissions before creating the Role and RoleBinding objects.

12.2.2. Running checkups by using the web console

Use the following procedures the first time you run checkups by using the web console. For additional checkups, click Run checkup on either checkup tab, and select the appropriate checkup from the drop down menu.

12.2.2.1. Running a latency checkup by using the web console

Run a latency checkup to verify network connectivity and measure the latency between two virtual machines attached to a secondary network interface.

Prerequisites

  • You must add a NetworkAttachmentDefinition to the namespace.

Procedure

  1. Navigate to VirtualizationCheckups in the web console.
  2. Click the Network latency tab.
  3. Click Install permissions.
  4. Click Run checkup.
  5. Enter a name for the checkup in the Name field.
  6. Select a NetworkAttachmentDefinition from the drop-down menu.
  7. Optional: Set a duration for the latency sample in the Sample duration (seconds) field.
  8. Optional: Define a maximum latency time interval by enabling Set maximum desired latency (milliseconds) and defining the time interval.
  9. Optional: Target specific nodes by enabling Select nodes and specifying the Source node and Target node.
  10. Click Run.

You can view the status of the latency checkup in the Checkups list on the Latency checkup tab. Click on the name of the checkup for more details.

12.2.2.2. Running a storage checkup by using the web console

Run a storage checkup to validate that storage is working correctly for virtual machines.

Procedure

  1. Navigate to VirtualizationCheckups in the web console.
  2. Click the Storage tab.
  3. Click Install permissions.
  4. Click Run checkup.
  5. Enter a name for the checkup in the Name field.
  6. Enter a timeout value for the checkup in the Timeout (minutes) fields.
  7. Click Run.

You can view the status of the storage checkup in the Checkups list on the Storage tab. Click on the name of the checkup for more details.

12.2.3. Running checkups by using the command line

Use the following procedures the first time you run checkups by using the command line.

12.2.3.1. Running a latency checkup by using the command line

You use a predefined checkup to verify network connectivity and measure latency between two virtual machines (VMs) that are attached to a secondary network interface. The latency checkup uses the ping utility.

You run a latency checkup by performing the following steps:

  1. Create a service account, roles, and rolebindings to provide cluster access permissions to the latency checkup.
  2. Create a config map to provide the input to run the checkup and to store the results.
  3. Create a job to run the checkup.
  4. Review the results in the config map.
  5. Optional: To rerun the checkup, delete the existing config map and job and then create a new config map and job.
  6. When you are finished, delete the latency checkup resources.

Prerequisites

  • You installed the OpenShift CLI (oc).
  • The cluster has at least two worker nodes.
  • You configured a network attachment definition for a namespace.

Procedure

  1. Create a ServiceAccount, Role, and RoleBinding manifest for the latency checkup:

    Example 12.1. Example role manifest file

    ---
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      name: vm-latency-checkup-sa
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: Role
    metadata:
      name: kubevirt-vm-latency-checker
    rules:
    - apiGroups: ["kubevirt.io"]
      resources: ["virtualmachineinstances"]
      verbs: ["get", "create", "delete"]
    - apiGroups: ["subresources.kubevirt.io"]
      resources: ["virtualmachineinstances/console"]
      verbs: ["get"]
    - apiGroups: ["k8s.cni.cncf.io"]
      resources: ["network-attachment-definitions"]
      verbs: ["get"]
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: kubevirt-vm-latency-checker
    subjects:
    - kind: ServiceAccount
      name: vm-latency-checkup-sa
    roleRef:
      kind: Role
      name: kubevirt-vm-latency-checker
      apiGroup: rbac.authorization.k8s.io
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: Role
    metadata:
      name: kiagnose-configmap-access
    rules:
    - apiGroups: [ "" ]
      resources: [ "configmaps" ]
      verbs: ["get", "update"]
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: kiagnose-configmap-access
    subjects:
    - kind: ServiceAccount
      name: vm-latency-checkup-sa
    roleRef:
      kind: Role
      name: kiagnose-configmap-access
      apiGroup: rbac.authorization.k8s.io
  2. Apply the ServiceAccount, Role, and RoleBinding manifest:

    $ oc apply -n <target_namespace> -f <latency_sa_roles_rolebinding>.yaml 1
    1
    <target_namespace> is the namespace where the checkup is to be run. This must be an existing namespace where the NetworkAttachmentDefinition object resides.
  3. Create a ConfigMap manifest that contains the input parameters for the checkup:

    Example input config map

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: kubevirt-vm-latency-checkup-config
      labels:
        kiagnose/checkup-type: kubevirt-vm-latency
    data:
      spec.timeout: 5m
      spec.param.networkAttachmentDefinitionNamespace: <target_namespace>
      spec.param.networkAttachmentDefinitionName: "blue-network" 1
      spec.param.maxDesiredLatencyMilliseconds: "10" 2
      spec.param.sampleDurationSeconds: "5" 3
      spec.param.sourceNode: "worker1" 4
      spec.param.targetNode: "worker2" 5

    1
    The name of the NetworkAttachmentDefinition object.
    2
    Optional: The maximum desired latency, in milliseconds, between the virtual machines. If the measured latency exceeds this value, the checkup fails.
    3
    Optional: The duration of the latency check, in seconds.
    4
    Optional: When specified, latency is measured from this node to the target node. If the source node is specified, the spec.param.targetNode field cannot be empty.
    5
    Optional: When specified, latency is measured from the source node to this node.
  4. Apply the config map manifest in the target namespace:

    $ oc apply -n <target_namespace> -f <latency_config_map>.yaml
  5. Create a Job manifest to run the checkup:

    Example job manifest

    apiVersion: batch/v1
    kind: Job
    metadata:
      name: kubevirt-vm-latency-checkup
      labels:
        kiagnose/checkup-type: kubevirt-vm-latency
    spec:
      backoffLimit: 0
      template:
        spec:
          serviceAccountName: vm-latency-checkup-sa
          restartPolicy: Never
          containers:
            - name: vm-latency-checkup
              image: registry.redhat.io/container-native-virtualization/vm-network-latency-checkup-rhel9:v4.17.0
              securityContext:
                allowPrivilegeEscalation: false
                capabilities:
                  drop: ["ALL"]
                runAsNonRoot: true
                seccompProfile:
                  type: "RuntimeDefault"
              env:
                - name: CONFIGMAP_NAMESPACE
                  value: <target_namespace>
                - name: CONFIGMAP_NAME
                  value: kubevirt-vm-latency-checkup-config
                - name: POD_UID
                  valueFrom:
                    fieldRef:
                      fieldPath: metadata.uid

  6. Apply the Job manifest:

    $ oc apply -n <target_namespace> -f <latency_job>.yaml
  7. Wait for the job to complete:

    $ oc wait job kubevirt-vm-latency-checkup -n <target_namespace> --for condition=complete --timeout 6m
  8. Review the results of the latency checkup by running the following command. If the maximum measured latency is greater than the value of the spec.param.maxDesiredLatencyMilliseconds attribute, the checkup fails and returns an error.

    $ oc get configmap kubevirt-vm-latency-checkup-config -n <target_namespace> -o yaml

    Example output config map (success)

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: kubevirt-vm-latency-checkup-config
      namespace: <target_namespace>
      labels:
        kiagnose/checkup-type: kubevirt-vm-latency
    data:
      spec.timeout: 5m
      spec.param.networkAttachmentDefinitionNamespace: <target_namespace>
      spec.param.networkAttachmentDefinitionName: "blue-network"
      spec.param.maxDesiredLatencyMilliseconds: "10"
      spec.param.sampleDurationSeconds: "5"
      spec.param.sourceNode: "worker1"
      spec.param.targetNode: "worker2"
      status.succeeded: "true"
      status.failureReason: ""
      status.completionTimestamp: "2022-01-01T09:00:00Z"
      status.startTimestamp: "2022-01-01T09:00:07Z"
      status.result.avgLatencyNanoSec: "177000"
      status.result.maxLatencyNanoSec: "244000" 1
      status.result.measurementDurationSec: "5"
      status.result.minLatencyNanoSec: "135000"
      status.result.sourceNode: "worker1"
      status.result.targetNode: "worker2"

    1
    The maximum measured latency in nanoseconds.
  9. Optional: To view the detailed job log in case of checkup failure, use the following command:

    $ oc logs job.batch/kubevirt-vm-latency-checkup -n <target_namespace>
  10. Delete the job and config map that you previously created by running the following commands:

    $ oc delete job -n <target_namespace> kubevirt-vm-latency-checkup
    $ oc delete config-map -n <target_namespace> kubevirt-vm-latency-checkup-config
  11. Optional: If you do not plan to run another checkup, delete the roles manifest:

    $ oc delete -f <latency_sa_roles_rolebinding>.yaml
12.2.3.2. Running a storage checkup by using the command line

Use a predefined checkup to verify that the OpenShift Container Platform cluster storage is configured optimally to run OpenShift Virtualization workloads.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • The cluster administrator has created the required cluster-reader permissions for the storage checkup service account and namespace, such as in the following example:

    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRoleBinding
    metadata:
      name: kubevirt-storage-checkup-clustereader
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: ClusterRole
      name: cluster-reader
    subjects:
    - kind: ServiceAccount
      name: storage-checkup-sa
      namespace: <target_namespace> 1
    1
    The namespace where the checkup is to be run.

Procedure

  1. Create a ServiceAccount, Role, and RoleBinding manifest file for the storage checkup:

    Example 12.2. Example service account, role, and rolebinding manifest

    ---
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      name: storage-checkup-sa
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: Role
    metadata:
      name: storage-checkup-role
    rules:
      - apiGroups: [ "" ]
        resources: [ "configmaps" ]
        verbs: ["get", "update"]
      - apiGroups: [ "kubevirt.io" ]
        resources: [ "virtualmachines" ]
        verbs: [ "create", "delete" ]
      - apiGroups: [ "kubevirt.io" ]
        resources: [ "virtualmachineinstances" ]
        verbs: [ "get" ]
      - apiGroups: [ "subresources.kubevirt.io" ]
        resources: [ "virtualmachineinstances/addvolume", "virtualmachineinstances/removevolume" ]
        verbs: [ "update" ]
      - apiGroups: [ "kubevirt.io" ]
        resources: [ "virtualmachineinstancemigrations" ]
        verbs: [ "create" ]
      - apiGroups: [ "cdi.kubevirt.io" ]
        resources: [ "datavolumes" ]
        verbs: [ "create", "delete" ]
      - apiGroups: [ "" ]
        resources: [ "persistentvolumeclaims" ]
        verbs: [ "delete" ]
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: storage-checkup-role
    subjects:
      - kind: ServiceAccount
        name: storage-checkup-sa
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: Role
      name: storage-checkup-role
  2. Apply the ServiceAccount, Role, and RoleBinding manifest in the target namespace:

    $ oc apply -n <target_namespace> -f <storage_sa_roles_rolebinding>.yaml
  3. Create a ConfigMap and Job manifest file. The config map contains the input parameters for the checkup job.

    Example input config map and job manifest

    ---
    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: storage-checkup-config
      namespace: $CHECKUP_NAMESPACE
    data:
      spec.timeout: 10m
      spec.param.storageClass: ocs-storagecluster-ceph-rbd-virtualization
      spec.param.vmiTimeout: 3m
    ---
    apiVersion: batch/v1
    kind: Job
    metadata:
      name: storage-checkup
      namespace: $CHECKUP_NAMESPACE
    spec:
      backoffLimit: 0
      template:
        spec:
          serviceAccount: storage-checkup-sa
          restartPolicy: Never
          containers:
            - name: storage-checkup
              image: quay.io/kiagnose/kubevirt-storage-checkup:main
              imagePullPolicy: Always
              env:
                - name: CONFIGMAP_NAMESPACE
                  value: $CHECKUP_NAMESPACE
                - name: CONFIGMAP_NAME
                  value: storage-checkup-config

  4. Apply the ConfigMap and Job manifest file in the target namespace to run the checkup:

    $ oc apply -n <target_namespace> -f <storage_configmap_job>.yaml
  5. Wait for the job to complete:

    $ oc wait job storage-checkup -n <target_namespace> --for condition=complete --timeout 10m
  6. Review the results of the checkup by running the following command:

    $ oc get configmap storage-checkup-config -n <target_namespace> -o yaml

    Example output config map (success)

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: storage-checkup-config
      labels:
        kiagnose/checkup-type: kubevirt-storage
    data:
      spec.timeout: 10m
      status.succeeded: "true" 1
      status.failureReason: "" 2
      status.startTimestamp: "2023-07-31T13:14:38Z" 3
      status.completionTimestamp: "2023-07-31T13:19:41Z" 4
      status.result.cnvVersion: 4.17.2 5
      status.result.defaultStorageClass: trident-nfs 6
      status.result.goldenImagesNoDataSource: <data_import_cron_list> 7
      status.result.goldenImagesNotUpToDate: <data_import_cron_list> 8
      status.result.ocpVersion: 4.17.0 9
      status.result.pvcBound: "true" 10
      status.result.storageProfileMissingVolumeSnapshotClass: <storage_class_list> 11
      status.result.storageProfilesWithEmptyClaimPropertySets: <storage_profile_list> 12
      status.result.storageProfilesWithSmartClone: <storage_profile_list> 13
      status.result.storageProfilesWithSpecClaimPropertySets: <storage_profile_list> 14
      status.result.storageProfilesWithRWX: |-
        ocs-storagecluster-ceph-rbd
        ocs-storagecluster-ceph-rbd-virtualization
        ocs-storagecluster-cephfs
        trident-iscsi
        trident-minio
        trident-nfs
        windows-vms
      status.result.vmBootFromGoldenImage: VMI "vmi-under-test-dhkb8" successfully booted
      status.result.vmHotplugVolume: |-
        VMI "vmi-under-test-dhkb8" hotplug volume ready
        VMI "vmi-under-test-dhkb8" hotplug volume removed
      status.result.vmLiveMigration: VMI "vmi-under-test-dhkb8" migration completed
      status.result.vmVolumeClone: 'DV cloneType: "csi-clone"'
      status.result.vmsWithNonVirtRbdStorageClass: <vm_list> 15
      status.result.vmsWithUnsetEfsStorageClass: <vm_list> 16

    1
    Specifies if the checkup is successful (true) or not (false).
    2
    The reason for failure if the checkup fails.
    3
    The time when the checkup started, in RFC 3339 time format.
    4
    The time when the checkup has completed, in RFC 3339 time format.
    5
    The OpenShift Virtualization version.
    6
    Specifies if there is a default storage class.
    7
    The list of golden images whose data source is not ready.
    8
    The list of golden images whose data import cron is not up-to-date.
    9
    The OpenShift Container Platform version.
    10
    Specifies if a PVC of 10Mi has been created and bound by the provisioner.
    11
    The list of storage profiles using snapshot-based clone but missing VolumeSnapshotClass.
    12
    The list of storage profiles with unknown provisioners.
    13
    The list of storage profiles with smart clone support (CSI/snapshot).
    14
    The list of storage profiles spec-overriden claimPropertySets.
    15
    The list of virtual machines that use the Ceph RBD storage class when the virtualization storage class exists.
    16
    The list of virtual machines that use an Elastic File Store (EFS) storage class where the GID and UID are not set in the storage class.
  7. Delete the job and config map that you previously created by running the following commands:

    $ oc delete job -n <target_namespace> storage-checkup
    $ oc delete config-map -n <target_namespace> storage-checkup-config
  8. Optional: If you do not plan to run another checkup, delete the ServiceAccount, Role, and RoleBinding manifest:

    $ oc delete -f <storage_sa_roles_rolebinding>.yaml
12.2.3.3. Running a DPDK checkup by using the command line

Use a predefined checkup to verify that your OpenShift Container Platform cluster node can run a virtual machine (VM) with a Data Plane Development Kit (DPDK) workload with zero packet loss. The DPDK checkup runs traffic between a traffic generator and a VM running a test DPDK application.

You run a DPDK checkup by performing the following steps:

  1. Create a service account, role, and role bindings for the DPDK checkup.
  2. Create a config map to provide the input to run the checkup and to store the results.
  3. Create a job to run the checkup.
  4. Review the results in the config map.
  5. Optional: To rerun the checkup, delete the existing config map and job and then create a new config map and job.
  6. When you are finished, delete the DPDK checkup resources.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • The cluster is configured to run DPDK applications.
  • The project is configured to run DPDK applications.

Procedure

  1. Create a ServiceAccount, Role, and RoleBinding manifest for the DPDK checkup:

    Example 12.3. Example service account, role, and rolebinding manifest file

    ---
    apiVersion: v1
    kind: ServiceAccount
    metadata:
      name: dpdk-checkup-sa
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: Role
    metadata:
      name: kiagnose-configmap-access
    rules:
      - apiGroups: [ "" ]
        resources: [ "configmaps" ]
        verbs: [ "get", "update" ]
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: kiagnose-configmap-access
    subjects:
      - kind: ServiceAccount
        name: dpdk-checkup-sa
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: Role
      name: kiagnose-configmap-access
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: Role
    metadata:
      name: kubevirt-dpdk-checker
    rules:
      - apiGroups: [ "kubevirt.io" ]
        resources: [ "virtualmachineinstances" ]
        verbs: [ "create", "get", "delete" ]
      - apiGroups: [ "subresources.kubevirt.io" ]
        resources: [ "virtualmachineinstances/console" ]
        verbs: [ "get" ]
      - apiGroups: [ "" ]
        resources: [ "configmaps" ]
        verbs: [ "create", "delete" ]
    ---
    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: kubevirt-dpdk-checker
    subjects:
      - kind: ServiceAccount
        name: dpdk-checkup-sa
    roleRef:
      apiGroup: rbac.authorization.k8s.io
      kind: Role
      name: kubevirt-dpdk-checker
  2. Apply the ServiceAccount, Role, and RoleBinding manifest:

    $ oc apply -n <target_namespace> -f <dpdk_sa_roles_rolebinding>.yaml
  3. Create a ConfigMap manifest that contains the input parameters for the checkup:

    Example input config map

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: dpdk-checkup-config
      labels:
        kiagnose/checkup-type: kubevirt-dpdk
    data:
      spec.timeout: 10m
      spec.param.networkAttachmentDefinitionName: <network_name> 1
      spec.param.trafficGenContainerDiskImage: "quay.io/kiagnose/kubevirt-dpdk-checkup-traffic-gen:v0.4.0 2
      spec.param.vmUnderTestContainerDiskImage: "quay.io/kiagnose/kubevirt-dpdk-checkup-vm:v0.4.0" 3

    1
    The name of the NetworkAttachmentDefinition object.
    2
    The container disk image for the traffic generator. In this example, the image is pulled from the upstream Project Quay Container Registry.
    3
    The container disk image for the VM under test. In this example, the image is pulled from the upstream Project Quay Container Registry.
  4. Apply the ConfigMap manifest in the target namespace:

    $ oc apply -n <target_namespace> -f <dpdk_config_map>.yaml
  5. Create a Job manifest to run the checkup:

    Example job manifest

    apiVersion: batch/v1
    kind: Job
    metadata:
      name: dpdk-checkup
      labels:
        kiagnose/checkup-type: kubevirt-dpdk
    spec:
      backoffLimit: 0
      template:
        spec:
          serviceAccountName: dpdk-checkup-sa
          restartPolicy: Never
          containers:
            - name: dpdk-checkup
              image: registry.redhat.io/container-native-virtualization/kubevirt-dpdk-checkup-rhel9:v4.17.0
              imagePullPolicy: Always
              securityContext:
                allowPrivilegeEscalation: false
                capabilities:
                  drop: ["ALL"]
                runAsNonRoot: true
                seccompProfile:
                  type: "RuntimeDefault"
              env:
                - name: CONFIGMAP_NAMESPACE
                  value: <target-namespace>
                - name: CONFIGMAP_NAME
                  value: dpdk-checkup-config
                - name: POD_UID
                  valueFrom:
                    fieldRef:
                      fieldPath: metadata.uid

  6. Apply the Job manifest:

    $ oc apply -n <target_namespace> -f <dpdk_job>.yaml
  7. Wait for the job to complete:

    $ oc wait job dpdk-checkup -n <target_namespace> --for condition=complete --timeout 10m
  8. Review the results of the checkup by running the following command:

    $ oc get configmap dpdk-checkup-config -n <target_namespace> -o yaml

    Example output config map (success)

    apiVersion: v1
    kind: ConfigMap
    metadata:
      name: dpdk-checkup-config
      labels:
        kiagnose/checkup-type: kubevirt-dpdk
    data:
      spec.timeout: 10m
      spec.param.NetworkAttachmentDefinitionName: "dpdk-network-1"
      spec.param.trafficGenContainerDiskImage: "quay.io/kiagnose/kubevirt-dpdk-checkup-traffic-gen:v0.4.0"
      spec.param.vmUnderTestContainerDiskImage: "quay.io/kiagnose/kubevirt-dpdk-checkup-vm:v0.4.0"
      status.succeeded: "true" 1
      status.failureReason: "" 2
      status.startTimestamp: "2023-07-31T13:14:38Z" 3
      status.completionTimestamp: "2023-07-31T13:19:41Z" 4
      status.result.trafficGenSentPackets: "480000000" 5
      status.result.trafficGenOutputErrorPackets: "0" 6
      status.result.trafficGenInputErrorPackets: "0" 7
      status.result.trafficGenActualNodeName: worker-dpdk1 8
      status.result.vmUnderTestActualNodeName: worker-dpdk2 9
      status.result.vmUnderTestReceivedPackets: "480000000" 10
      status.result.vmUnderTestRxDroppedPackets: "0" 11
      status.result.vmUnderTestTxDroppedPackets: "0" 12

    1
    Specifies if the checkup is successful (true) or not (false).
    2
    The reason for failure if the checkup fails.
    3
    The time when the checkup started, in RFC 3339 time format.
    4
    The time when the checkup has completed, in RFC 3339 time format.
    5
    The number of packets sent from the traffic generator.
    6
    The number of error packets sent from the traffic generator.
    7
    The number of error packets received by the traffic generator.
    8
    The node on which the traffic generator VM was scheduled.
    9
    The node on which the VM under test was scheduled.
    10
    The number of packets received on the VM under test.
    11
    The ingress traffic packets that were dropped by the DPDK application.
    12
    The egress traffic packets that were dropped from the DPDK application.
  9. Delete the job and config map that you previously created by running the following commands:

    $ oc delete job -n <target_namespace> dpdk-checkup
    $ oc delete config-map -n <target_namespace> dpdk-checkup-config
  10. Optional: If you do not plan to run another checkup, delete the ServiceAccount, Role, and RoleBinding manifest:

    $ oc delete -f <dpdk_sa_roles_rolebinding>.yaml
12.2.3.3.1. DPDK checkup config map parameters

The following table shows the mandatory and optional parameters that you can set in the data stanza of the input ConfigMap manifest when you run a cluster DPDK readiness checkup:

Table 12.1. DPDK checkup config map input parameters
ParameterDescriptionIs Mandatory

spec.timeout

The time, in minutes, before the checkup fails.

True

spec.param.networkAttachmentDefinitionName

The name of the NetworkAttachmentDefinition object of the SR-IOV NICs connected.

True

spec.param.trafficGenContainerDiskImage

The container disk image for the traffic generator.

True

spec.param.trafficGenTargetNodeName

The node on which the traffic generator VM is to be scheduled. The node should be configured to allow DPDK traffic.

False

spec.param.trafficGenPacketsPerSecond

The number of packets per second, in kilo (k) or million(m). The default value is 8m.

False

spec.param.vmUnderTestContainerDiskImage

The container disk image for the VM under test.

True

spec.param.vmUnderTestTargetNodeName

The node on which the VM under test is to be scheduled. The node should be configured to allow DPDK traffic.

False

spec.param.testDuration

The duration, in minutes, for which the traffic generator runs. The default value is 5 minutes.

False

spec.param.portBandwidthGbps

The maximum bandwidth of the SR-IOV NIC. The default value is 10Gbps.

False

spec.param.verbose

When set to true, it increases the verbosity of the checkup log. The default value is false.

False

12.2.3.3.2. Building a container disk image for RHEL virtual machines

You can build a custom Red Hat Enterprise Linux (RHEL) 9 OS image in qcow2 format and use it to create a container disk image. You can store the container disk image in a registry that is accessible from your cluster and specify the image location in the spec.param.vmContainerDiskImage attribute of the DPDK checkup config map.

To build a container disk image, you must create an image builder virtual machine (VM). The image builder VM is a RHEL 9 VM that can be used to build custom RHEL images.

Prerequisites

  • The image builder VM must run RHEL 9.4 and must have a minimum of 2 CPU cores, 4 GiB RAM, and 20 GB of free space in the /var directory.
  • You have installed the image builder tool and its CLI (composer-cli) on the VM. For more information, see "Additional resources".
  • You have installed the virt-customize tool:

    # dnf install guestfs-tools
  • You have installed the Podman CLI tool (podman).

Procedure

  1. Verify that you can build a RHEL 9.4 image:

    # composer-cli distros list
    Note

    To run the composer-cli commands as non-root, add your user to the weldr or root groups:

    # usermod -a -G weldr <user>
    $ newgrp weldr
  2. Enter the following command to create an image blueprint file in TOML format that contains the packages to be installed, kernel customizations, and the services to be disabled during boot time:

    $ cat << EOF > dpdk-vm.toml
    name = "dpdk_image"
    description = "Image to use with the DPDK checkup"
    version = "0.0.1"
    distro = "rhel-9.4"
    
    [[customizations.user]]
    name = "root"
    password = "redhat"
    
    [[packages]]
    name = "dpdk"
    
    [[packages]]
    name = "dpdk-tools"
    
    [[packages]]
    name = "driverctl"
    
    [[packages]]
    name = "tuned-profiles-cpu-partitioning"
    
    [customizations.kernel]
    append = "default_hugepagesz=1GB hugepagesz=1G hugepages=1"
    
    [customizations.services]
    disabled = ["NetworkManager-wait-online", "sshd"]
    EOF
  3. Push the blueprint file to the image builder tool by running the following command:

    # composer-cli blueprints push dpdk-vm.toml
  4. Generate the system image by specifying the blueprint name and output file format. The Universally Unique Identifier (UUID) of the image is displayed when you start the compose process.

    # composer-cli compose start dpdk_image qcow2
  5. Wait for the compose process to complete. The compose status must show FINISHED before you can continue to the next step.

    # composer-cli compose status
  6. Enter the following command to download the qcow2 image file by specifying its UUID:

    # composer-cli compose image <UUID>
  7. Create the customization scripts by running the following commands:

    $ cat <<EOF >customize-vm
    #!/bin/bash
    
    # Setup hugepages mount
    mkdir -p /mnt/huge
    echo "hugetlbfs /mnt/huge hugetlbfs defaults,pagesize=1GB 0 0" >> /etc/fstab
    
    # Create vfio-noiommu.conf
    echo "options vfio enable_unsafe_noiommu_mode=1" > /etc/modprobe.d/vfio-noiommu.conf
    
    # Enable guest-exec,guest-exec-status on the qemu-guest-agent configuration
    sed -i 's/\(--allow-rpcs=[^"]*\)/\1,guest-exec-status,guest-exec/' /etc/sysconfig/qemu-ga
    
    # Disable Bracketed-paste mode
    echo "set enable-bracketed-paste off" >> /root/.inputrc
    EOF
  8. Use the virt-customize tool to customize the image generated by the image builder tool:

    $ virt-customize -a <UUID>-disk.qcow2 --run=customize-vm --selinux-relabel
  9. To create a Dockerfile that contains all the commands to build the container disk image, enter the following command:

    $ cat << EOF > Dockerfile
    FROM scratch
    COPY --chown=107:107 <UUID>-disk.qcow2 /disk/
    EOF

    where:

    <UUID>-disk.qcow2
    Specifies the name of the custom image in qcow2 format.
  10. Build and tag the container by running the following command:

    $ podman build . -t dpdk-rhel:latest
  11. Push the container disk image to a registry that is accessible from your cluster by running the following command:

    $ podman push dpdk-rhel:latest
  12. Provide a link to the container disk image in the spec.param.vmUnderTestContainerDiskImage attribute in the DPDK checkup config map.

12.2.4. Additional resources

12.3. Prometheus queries for virtual resources

OpenShift Virtualization provides metrics that you can use to monitor the consumption of cluster infrastructure resources, including vCPU, network, storage, and guest memory swapping. You can also use metrics to query live migration status.

12.3.1. Prerequisites

  • To use the vCPU metric, the schedstats=enable kernel argument must be applied to the MachineConfig object. This kernel argument enables scheduler statistics used for debugging and performance tuning and adds a minor additional load to the scheduler. For more information, see Adding kernel arguments to nodes.
  • For guest memory swapping queries to return data, memory swapping must be enabled on the virtual guests.

12.3.2. Querying metrics

The OpenShift Container Platform monitoring dashboard enables you to run Prometheus Query Language (PromQL) queries to examine metrics visualized on a plot. This functionality provides information about the state of a cluster and any user-defined workloads that you are monitoring.

As a cluster administrator, you can query metrics for all core OpenShift Container Platform and user-defined projects.

As a developer, you must specify a project name when querying metrics. You must have the required privileges to view metrics for the selected project.

12.3.2.1. Querying metrics for all projects as a cluster administrator

As a cluster administrator or as a user with view permissions for all projects, you can access metrics for all default OpenShift Container Platform and user-defined projects in the Metrics UI.

Prerequisites

  • You have access to the cluster as a user with the cluster-admin cluster role or with view permissions for all projects.
  • You have installed the OpenShift CLI (oc).

Procedure

  1. From the Administrator perspective in the OpenShift Container Platform web console, select ObserveMetrics.
  2. To add one or more queries, do any of the following:

    OptionDescription

    Create a custom query.

    Add your Prometheus Query Language (PromQL) query to the Expression field.

    As you type a PromQL expression, autocomplete suggestions appear in a drop-down list. These suggestions include functions, metrics, labels, and time tokens. You can use the keyboard arrows to select one of these suggested items and then press Enter to add the item to your expression. You can also move your mouse pointer over a suggested item to view a brief description of that item.

    Add multiple queries.

    Select Add query.

    Duplicate an existing query.

    Select the Options menu kebab next to the query, then choose Duplicate query.

    Disable a query from being run.

    Select the Options menu kebab next to the query and choose Disable query.

  3. To run queries that you created, select Run queries. The metrics from the queries are visualized on the plot. If a query is invalid, the UI shows an error message.

    Note

    Queries that operate on large amounts of data might time out or overload the browser when drawing time series graphs. To avoid this, select Hide graph and calibrate your query using only the metrics table. Then, after finding a feasible query, enable the plot to draw the graphs.

    Note

    By default, the query table shows an expanded view that lists every metric and its current value. You can select ˅ to minimize the expanded view for a query.

  4. Optional: The page URL now contains the queries you ran. To use this set of queries again in the future, save this URL.
  5. Explore the visualized metrics. Initially, all metrics from all enabled queries are shown on the plot. You can select which metrics are shown by doing any of the following:

    OptionDescription

    Hide all metrics from a query.

    Click the Options menu kebab for the query and click Hide all series.

    Hide a specific metric.

    Go to the query table and click the colored square near the metric name.

    Zoom into the plot and change the time range.

    Either:

    • Visually select the time range by clicking and dragging on the plot horizontally.
    • Use the menu in the left upper corner to select the time range.

    Reset the time range.

    Select Reset zoom.

    Display outputs for all queries at a specific point in time.

    Hold the mouse cursor on the plot at that point. The query outputs will appear in a pop-up box.

    Hide the plot.

    Select Hide graph.

12.3.2.2. Querying metrics for user-defined projects as a developer

You can access metrics for a user-defined project as a developer or as a user with view permissions for the project.

In the Developer perspective, the Metrics UI includes some predefined CPU, memory, bandwidth, and network packet queries for the selected project. You can also run custom Prometheus Query Language (PromQL) queries for CPU, memory, bandwidth, network packet and application metrics for the project.

Note

Developers can only use the Developer perspective and not the Administrator perspective. As a developer, you can only query metrics for one project at a time.

Prerequisites

  • You have access to the cluster as a developer or as a user with view permissions for the project that you are viewing metrics for.
  • You have enabled monitoring for user-defined projects.
  • You have deployed a service in a user-defined project.
  • You have created a ServiceMonitor custom resource definition (CRD) for the service to define how the service is monitored.

Procedure

  1. From the Developer perspective in the OpenShift Container Platform web console, select ObserveMetrics.
  2. Select the project that you want to view metrics for in the Project: list.
  3. Select a query from the Select query list, or create a custom PromQL query based on the selected query by selecting Show PromQL. The metrics from the queries are visualized on the plot.

    Note

    In the Developer perspective, you can only run one query at a time.

  4. Explore the visualized metrics by doing any of the following:

    OptionDescription

    Zoom into the plot and change the time range.

    Either:

    • Visually select the time range by clicking and dragging on the plot horizontally.
    • Use the menu in the left upper corner to select the time range.

    Reset the time range.

    Select Reset zoom.

    Display outputs for all queries at a specific point in time.

    Hold the mouse cursor on the plot at that point. The query outputs appear in a pop-up box.

12.3.3. Virtualization metrics

The following metric descriptions include example Prometheus Query Language (PromQL) queries. These metrics are not an API and might change between versions. For a complete list of virtualization metrics, see KubeVirt components metrics.

Note

The following examples use topk queries that specify a time period. If virtual machines are deleted during that time period, they can still appear in the query output.

12.3.3.1. vCPU metrics

The following query can identify virtual machines that are waiting for Input/Output (I/O):

kubevirt_vmi_vcpu_wait_seconds_total
Returns the wait time (in seconds) for a virtual machine’s vCPU. Type: Counter.

A value above '0' means that the vCPU wants to run, but the host scheduler cannot run it yet. This inability to run indicates that there is an issue with I/O.

Note

To query the vCPU metric, the schedstats=enable kernel argument must first be applied to the MachineConfig object. This kernel argument enables scheduler statistics used for debugging and performance tuning and adds a minor additional load to the scheduler.

Example vCPU wait time query

topk(3, sum by (name, namespace) (rate(kubevirt_vmi_vcpu_wait_seconds_total[6m]))) > 0 1

1
This query returns the top 3 VMs waiting for I/O at every given moment over a six-minute time period.
12.3.3.2. Network metrics

The following queries can identify virtual machines that are saturating the network:

kubevirt_vmi_network_receive_bytes_total
Returns the total amount of traffic received (in bytes) on the virtual machine’s network. Type: Counter.
kubevirt_vmi_network_transmit_bytes_total
Returns the total amount of traffic transmitted (in bytes) on the virtual machine’s network. Type: Counter.

Example network traffic query

topk(3, sum by (name, namespace) (rate(kubevirt_vmi_network_receive_bytes_total[6m])) + sum by (name, namespace) (rate(kubevirt_vmi_network_transmit_bytes_total[6m]))) > 0 1

1
This query returns the top 3 VMs transmitting the most network traffic at every given moment over a six-minute time period.
12.3.3.3. Storage metrics
12.3.3.3.1. Storage-related traffic

The following queries can identify VMs that are writing large amounts of data:

kubevirt_vmi_storage_read_traffic_bytes_total
Returns the total amount (in bytes) of the virtual machine’s storage-related traffic. Type: Counter.
kubevirt_vmi_storage_write_traffic_bytes_total
Returns the total amount of storage writes (in bytes) of the virtual machine’s storage-related traffic. Type: Counter.

Example storage-related traffic query

topk(3, sum by (name, namespace) (rate(kubevirt_vmi_storage_read_traffic_bytes_total[6m])) + sum by (name, namespace) (rate(kubevirt_vmi_storage_write_traffic_bytes_total[6m]))) > 0 1

1
This query returns the top 3 VMs performing the most storage traffic at every given moment over a six-minute time period.
12.3.3.3.2. Storage snapshot data
kubevirt_vmsnapshot_disks_restored_from_source
Returns the total number of virtual machine disks restored from the source virtual machine. Type: Gauge.
kubevirt_vmsnapshot_disks_restored_from_source_bytes
Returns the amount of space in bytes restored from the source virtual machine. Type: Gauge.

Examples of storage snapshot data queries

kubevirt_vmsnapshot_disks_restored_from_source{vm_name="simple-vm", vm_namespace="default"} 1

1
This query returns the total number of virtual machine disks restored from the source virtual machine.
kubevirt_vmsnapshot_disks_restored_from_source_bytes{vm_name="simple-vm", vm_namespace="default"} 1
1
This query returns the amount of space in bytes restored from the source virtual machine.
12.3.3.3.3. I/O performance

The following queries can determine the I/O performance of storage devices:

kubevirt_vmi_storage_iops_read_total
Returns the amount of write I/O operations the virtual machine is performing per second. Type: Counter.
kubevirt_vmi_storage_iops_write_total
Returns the amount of read I/O operations the virtual machine is performing per second. Type: Counter.

Example I/O performance query

topk(3, sum by (name, namespace) (rate(kubevirt_vmi_storage_iops_read_total[6m])) + sum by (name, namespace) (rate(kubevirt_vmi_storage_iops_write_total[6m]))) > 0 1

1
This query returns the top 3 VMs performing the most I/O operations per second at every given moment over a six-minute time period.
12.3.3.4. Guest memory swapping metrics

The following queries can identify which swap-enabled guests are performing the most memory swapping:

kubevirt_vmi_memory_swap_in_traffic_bytes
Returns the total amount (in bytes) of memory the virtual guest is swapping in. Type: Gauge.
kubevirt_vmi_memory_swap_out_traffic_bytes
Returns the total amount (in bytes) of memory the virtual guest is swapping out. Type: Gauge.

Example memory swapping query

topk(3, sum by (name, namespace) (rate(kubevirt_vmi_memory_swap_in_traffic_bytes[6m])) + sum by (name, namespace) (rate(kubevirt_vmi_memory_swap_out_traffic_bytes[6m]))) > 0 1

1
This query returns the top 3 VMs where the guest is performing the most memory swapping at every given moment over a six-minute time period.
Note

Memory swapping indicates that the virtual machine is under memory pressure. Increasing the memory allocation of the virtual machine can mitigate this issue.

12.3.3.5. Live migration metrics

The following metrics can be queried to show live migration status:

kubevirt_vmi_migration_data_processed_bytes
The amount of guest operating system data that has migrated to the new virtual machine (VM). Type: Gauge.
kubevirt_vmi_migration_data_remaining_bytes
The amount of guest operating system data that remains to be migrated. Type: Gauge.
kubevirt_vmi_migration_memory_transfer_rate_bytes
The rate at which memory is becoming dirty in the guest operating system. Dirty memory is data that has been changed but not yet written to disk. Type: Gauge.
kubevirt_vmi_migrations_in_pending_phase
The number of pending migrations. Type: Gauge.
kubevirt_vmi_migrations_in_scheduling_phase
The number of scheduling migrations. Type: Gauge.
kubevirt_vmi_migrations_in_running_phase
The number of running migrations. Type: Gauge.
kubevirt_vmi_migration_succeeded
The number of successfully completed migrations. Type: Gauge.
kubevirt_vmi_migration_failed
The number of failed migrations. Type: Gauge.

12.3.4. Additional resources

12.4. Exposing custom metrics for virtual machines

OpenShift Container Platform includes a preconfigured, preinstalled, and self-updating monitoring stack that provides monitoring for core platform components. This monitoring stack is based on the Prometheus monitoring system. Prometheus is a time-series database and a rule evaluation engine for metrics.

In addition to using the OpenShift Container Platform monitoring stack, you can enable monitoring for user-defined projects by using the CLI and query custom metrics that are exposed for virtual machines through the node-exporter service.

12.4.1. Configuring the node exporter service

The node-exporter agent is deployed on every virtual machine in the cluster from which you want to collect metrics. Configure the node-exporter agent as a service to expose internal metrics and processes that are associated with virtual machines.

Prerequisites

  • Install the OpenShift Container Platform CLI oc.
  • Log in to the cluster as a user with cluster-admin privileges.
  • Create the cluster-monitoring-config ConfigMap object in the openshift-monitoring project.
  • Configure the user-workload-monitoring-config ConfigMap object in the openshift-user-workload-monitoring project by setting enableUserWorkload to true.

Procedure

  1. Create the Service YAML file. In the following example, the file is called node-exporter-service.yaml.

    kind: Service
    apiVersion: v1
    metadata:
      name: node-exporter-service 1
      namespace: dynamation 2
      labels:
        servicetype: metrics 3
    spec:
      ports:
        - name: exmet 4
          protocol: TCP
          port: 9100 5
          targetPort: 9100 6
      type: ClusterIP
      selector:
        monitor: metrics 7
    1
    The node-exporter service that exposes the metrics from the virtual machines.
    2
    The namespace where the service is created.
    3
    The label for the service. The ServiceMonitor uses this label to match this service.
    4
    The name given to the port that exposes metrics on port 9100 for the ClusterIP service.
    5
    The target port used by node-exporter-service to listen for requests.
    6
    The TCP port number of the virtual machine that is configured with the monitor label.
    7
    The label used to match the virtual machine’s pods. In this example, any virtual machine’s pod with the label monitor and a value of metrics will be matched.
  2. Create the node-exporter service:

    $ oc create -f node-exporter-service.yaml

12.4.2. Configuring a virtual machine with the node exporter service

Download the node-exporter file on to the virtual machine. Then, create a systemd service that runs the node-exporter service when the virtual machine boots.

Prerequisites

  • The pods for the component are running in the openshift-user-workload-monitoring project.
  • Grant the monitoring-edit role to users who need to monitor this user-defined project.

Procedure

  1. Log on to the virtual machine.
  2. Download the node-exporter file on to the virtual machine by using the directory path that applies to the version of node-exporter file.

    $ wget https://github.com/prometheus/node_exporter/releases/download/v1.3.1/node_exporter-1.3.1.linux-amd64.tar.gz
  3. Extract the executable and place it in the /usr/bin directory.

    $ sudo tar xvf node_exporter-1.3.1.linux-amd64.tar.gz \
        --directory /usr/bin --strip 1 "*/node_exporter"
  4. Create a node_exporter.service file in this directory path: /etc/systemd/system. This systemd service file runs the node-exporter service when the virtual machine reboots.

    [Unit]
    Description=Prometheus Metrics Exporter
    After=network.target
    StartLimitIntervalSec=0
    
    [Service]
    Type=simple
    Restart=always
    RestartSec=1
    User=root
    ExecStart=/usr/bin/node_exporter
    
    [Install]
    WantedBy=multi-user.target
  5. Enable and start the systemd service.

    $ sudo systemctl enable node_exporter.service
    $ sudo systemctl start node_exporter.service

Verification

  • Verify that the node-exporter agent is reporting metrics from the virtual machine.

    $ curl http://localhost:9100/metrics

    Example output

    go_gc_duration_seconds{quantile="0"} 1.5244e-05
    go_gc_duration_seconds{quantile="0.25"} 3.0449e-05
    go_gc_duration_seconds{quantile="0.5"} 3.7913e-05

12.4.3. Creating a custom monitoring label for virtual machines

To enable queries to multiple virtual machines from a single service, add a custom label in the virtual machine’s YAML file.

Prerequisites

  • Install the OpenShift Container Platform CLI oc.
  • Log in as a user with cluster-admin privileges.
  • Access to the web console for stop and restart a virtual machine.

Procedure

  1. Edit the template spec of your virtual machine configuration file. In this example, the label monitor has the value metrics.

    spec:
      template:
        metadata:
          labels:
            monitor: metrics
  2. Stop and restart the virtual machine to create a new pod with the label name given to the monitor label.
12.4.3.1. Querying the node-exporter service for metrics

Metrics are exposed for virtual machines through an HTTP service endpoint under the /metrics canonical name. When you query for metrics, Prometheus directly scrapes the metrics from the metrics endpoint exposed by the virtual machines and presents these metrics for viewing.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges or the monitoring-edit role.
  • You have enabled monitoring for the user-defined project by configuring the node-exporter service.

Procedure

  1. Obtain the HTTP service endpoint by specifying the namespace for the service:

    $ oc get service -n <namespace> <node-exporter-service>
  2. To list all available metrics for the node-exporter service, query the metrics resource.

    $ curl http://<172.30.226.162:9100>/metrics | grep -vE "^#|^$"

    Example output

    node_arp_entries{device="eth0"} 1
    node_boot_time_seconds 1.643153218e+09
    node_context_switches_total 4.4938158e+07
    node_cooling_device_cur_state{name="0",type="Processor"} 0
    node_cooling_device_max_state{name="0",type="Processor"} 0
    node_cpu_guest_seconds_total{cpu="0",mode="nice"} 0
    node_cpu_guest_seconds_total{cpu="0",mode="user"} 0
    node_cpu_seconds_total{cpu="0",mode="idle"} 1.10586485e+06
    node_cpu_seconds_total{cpu="0",mode="iowait"} 37.61
    node_cpu_seconds_total{cpu="0",mode="irq"} 233.91
    node_cpu_seconds_total{cpu="0",mode="nice"} 551.47
    node_cpu_seconds_total{cpu="0",mode="softirq"} 87.3
    node_cpu_seconds_total{cpu="0",mode="steal"} 86.12
    node_cpu_seconds_total{cpu="0",mode="system"} 464.15
    node_cpu_seconds_total{cpu="0",mode="user"} 1075.2
    node_disk_discard_time_seconds_total{device="vda"} 0
    node_disk_discard_time_seconds_total{device="vdb"} 0
    node_disk_discarded_sectors_total{device="vda"} 0
    node_disk_discarded_sectors_total{device="vdb"} 0
    node_disk_discards_completed_total{device="vda"} 0
    node_disk_discards_completed_total{device="vdb"} 0
    node_disk_discards_merged_total{device="vda"} 0
    node_disk_discards_merged_total{device="vdb"} 0
    node_disk_info{device="vda",major="252",minor="0"} 1
    node_disk_info{device="vdb",major="252",minor="16"} 1
    node_disk_io_now{device="vda"} 0
    node_disk_io_now{device="vdb"} 0
    node_disk_io_time_seconds_total{device="vda"} 174
    node_disk_io_time_seconds_total{device="vdb"} 0.054
    node_disk_io_time_weighted_seconds_total{device="vda"} 259.79200000000003
    node_disk_io_time_weighted_seconds_total{device="vdb"} 0.039
    node_disk_read_bytes_total{device="vda"} 3.71867136e+08
    node_disk_read_bytes_total{device="vdb"} 366592
    node_disk_read_time_seconds_total{device="vda"} 19.128
    node_disk_read_time_seconds_total{device="vdb"} 0.039
    node_disk_reads_completed_total{device="vda"} 5619
    node_disk_reads_completed_total{device="vdb"} 96
    node_disk_reads_merged_total{device="vda"} 5
    node_disk_reads_merged_total{device="vdb"} 0
    node_disk_write_time_seconds_total{device="vda"} 240.66400000000002
    node_disk_write_time_seconds_total{device="vdb"} 0
    node_disk_writes_completed_total{device="vda"} 71584
    node_disk_writes_completed_total{device="vdb"} 0
    node_disk_writes_merged_total{device="vda"} 19761
    node_disk_writes_merged_total{device="vdb"} 0
    node_disk_written_bytes_total{device="vda"} 2.007924224e+09
    node_disk_written_bytes_total{device="vdb"} 0

12.4.4. Creating a ServiceMonitor resource for the node exporter service

You can use a Prometheus client library and scrape metrics from the /metrics endpoint to access and view the metrics exposed by the node-exporter service. Use a ServiceMonitor custom resource definition (CRD) to monitor the node exporter service.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges or the monitoring-edit role.
  • You have enabled monitoring for the user-defined project by configuring the node-exporter service.

Procedure

  1. Create a YAML file for the ServiceMonitor resource configuration. In this example, the service monitor matches any service with the label metrics and queries the exmet port every 30 seconds.

    apiVersion: monitoring.coreos.com/v1
    kind: ServiceMonitor
    metadata:
      labels:
        k8s-app: node-exporter-metrics-monitor
      name: node-exporter-metrics-monitor 1
      namespace: dynamation 2
    spec:
      endpoints:
      - interval: 30s 3
        port: exmet 4
        scheme: http
      selector:
        matchLabels:
          servicetype: metrics
    1
    The name of the ServiceMonitor.
    2
    The namespace where the ServiceMonitor is created.
    3
    The interval at which the port will be queried.
    4
    The name of the port that is queried every 30 seconds
  2. Create the ServiceMonitor configuration for the node-exporter service.

    $ oc create -f node-exporter-metrics-monitor.yaml
12.4.4.1. Accessing the node exporter service outside the cluster

You can access the node-exporter service outside the cluster and view the exposed metrics.

Prerequisites

  • You have access to the cluster as a user with cluster-admin privileges or the monitoring-edit role.
  • You have enabled monitoring for the user-defined project by configuring the node-exporter service.

Procedure

  1. Expose the node-exporter service.

    $ oc expose service -n <namespace> <node_exporter_service_name>
  2. Obtain the FQDN (Fully Qualified Domain Name) for the route.

    $ oc get route -o=custom-columns=NAME:.metadata.name,DNS:.spec.host

    Example output

    NAME                    DNS
    node-exporter-service   node-exporter-service-dynamation.apps.cluster.example.org

  3. Use the curl command to display metrics for the node-exporter service.

    $ curl -s http://node-exporter-service-dynamation.apps.cluster.example.org/metrics

    Example output

    go_gc_duration_seconds{quantile="0"} 1.5382e-05
    go_gc_duration_seconds{quantile="0.25"} 3.1163e-05
    go_gc_duration_seconds{quantile="0.5"} 3.8546e-05
    go_gc_duration_seconds{quantile="0.75"} 4.9139e-05
    go_gc_duration_seconds{quantile="1"} 0.000189423

12.4.5. Additional resources

12.5. Exposing downward metrics for virtual machines

As an administrator, you can expose a limited set of host and virtual machine (VM) metrics to a guest VM by first enabling a downwardMetrics feature gate and then configuring a downwardMetrics device.

Users can view the metrics results by using the command line or the vm-dump-metrics tool.

Note

On Red Hat Enterprise Linux (RHEL) 9, use the command line to view downward metrics. See Viewing downward metrics by using the command line.

The vm-dump-metrics tool is not supported on the Red Hat Enterprise Linux (RHEL) 9 platform.

12.5.1. Enabling or disabling the downwardMetrics feature gate

You can enable or disable the downwardMetrics feature gate by performing either of the following actions:

  • Editing the HyperConverged custom resource (CR) in your default editor
  • Using the command line
12.5.1.1. Enabling or disabling the downward metrics feature gate in a YAML file

To expose downward metrics for a host virtual machine, you can enable the downwardMetrics feature gate by editing a YAML file.

Prerequisites

  • You must have administrator privileges to enable the feature gate.

Procedure

  1. Open the HyperConverged custom resource (CR) in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Choose to enable or disable the downwardMetrics feature gate as follows:

    • To enable the downwardMetrics feature gate, add and then set spec.featureGates.downwardMetrics to true. For example:

      apiVersion: hco.kubevirt.io/v1beta1
      kind: HyperConverged
      metadata:
        name: kubevirt-hyperconverged
        namespace: openshift-cnv
      spec:
          featureGates:
            downwardMetrics: true
      # ...
    • To disable the downwardMetrics feature gate, set spec.featureGates.downwardMetrics to false. For example:

      apiVersion: hco.kubevirt.io/v1beta1
      kind: HyperConverged
      metadata:
        name: kubevirt-hyperconverged
        namespace: openshift-cnv
      spec:
          featureGates:
            downwardMetrics: false
      # ...
12.5.1.2. Enabling or disabling the downward metrics feature gate from the command line

To expose downward metrics for a host virtual machine, you can enable the downwardMetrics feature gate by using the command line.

Prerequisites

  • You must have administrator privileges to enable the feature gate.

Procedure

  • Choose to enable or disable the downwardMetrics feature gate as follows:

    • Enable the downwardMetrics feature gate by running the command shown in the following example:

      $ oc patch hco kubevirt-hyperconverged -n openshift-cnv \
        --type json -p '[{"op": "replace", "path": \
        "/spec/featureGates/downwardMetrics" \
        "value": true}]'
    • Disable the downwardMetrics feature gate by running the command shown in the following example:

      $ oc patch hco kubevirt-hyperconverged -n openshift-cnv \
        --type json -p '[{"op": "replace", "path": \
        "/spec/featureGates/downwardMetrics" \
        "value": false}]'

12.5.2. Configuring a downward metrics device

You enable the capturing of downward metrics for a host VM by creating a configuration file that includes a downwardMetrics device. Adding this device establishes that the metrics are exposed through a virtio-serial port.

Prerequisites

  • You must first enable the downwardMetrics feature gate.

Procedure

  • Edit or create a YAML file that includes a downwardMetrics device, as shown in the following example:

    Example downwardMetrics configuration file

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: fedora
      namespace: default
    spec:
      dataVolumeTemplates:
        - metadata:
            name: fedora-volume
          spec:
            sourceRef:
              kind: DataSource
              name: fedora
              namespace: openshift-virtualization-os-images
            storage:
              resources: {}
              storageClassName: hostpath-csi-basic
      instancetype:
        name: u1.medium
      preference:
        name: fedora
      running: true
      template:
        metadata:
          labels:
            app.kubernetes.io/name: headless
        spec:
          domain:
            devices:
              downwardMetrics: {} 1
          subdomain: headless
          volumes:
            - dataVolume:
                name: fedora-volume
              name: rootdisk
            - cloudInitNoCloud:
                userData: |
                  #cloud-config
                  chpasswd:
                    expire: false
                  password: '<password>' 2
                  user: fedora
              name: cloudinitdisk

    1
    The downwardMetrics device.
    2
    The password for the fedora user.

12.5.3. Viewing downward metrics

You can view downward metrics by using either of the following options:

  • The command line interface (CLI)
  • The vm-dump-metrics tool
Note

On Red Hat Enterprise Linux (RHEL) 9, use the command line to view downward metrics. The vm-dump-metrics tool is not supported on the Red Hat Enterprise Linux (RHEL) 9 platform.

12.5.3.1. Viewing downward metrics by using the command line

You can view downward metrics by entering a command from inside a guest virtual machine (VM).

Procedure

  • Run the following commands:

    $ sudo sh -c 'printf "GET /metrics/XML\n\n" > /dev/virtio-ports/org.github.vhostmd.1'
    $ sudo cat /dev/virtio-ports/org.github.vhostmd.1
12.5.3.2. Viewing downward metrics by using the vm-dump-metrics tool

To view downward metrics, install the vm-dump-metrics tool and then use the tool to expose the metrics results.

Note

On Red Hat Enterprise Linux (RHEL) 9, use the command line to view downward metrics. The vm-dump-metrics tool is not supported on the Red Hat Enterprise Linux (RHEL) 9 platform.

Procedure

  1. Install the vm-dump-metrics tool by running the following command:

    $ sudo dnf install -y vm-dump-metrics
  2. Retrieve the metrics results by running the following command:

    $ sudo vm-dump-metrics

    Example output

    <metrics>
      <metric type="string" context="host">
        <name>HostName</name>
        <value>node01</value>
    [...]
      <metric type="int64" context="host" unit="s">
        <name>Time</name>
        <value>1619008605</value>
      </metric>
      <metric type="string" context="host">
        <name>VirtualizationVendor</name>
        <value>kubevirt.io</value>
      </metric>
    </metrics>

12.6. Virtual machine health checks

You can configure virtual machine (VM) health checks by defining readiness and liveness probes in the VirtualMachine resource.

12.6.1. About readiness and liveness probes

Use readiness and liveness probes to detect and handle unhealthy virtual machines (VMs). You can include one or more probes in the specification of the VM to ensure that traffic does not reach a VM that is not ready for it and that a new VM is created when a VM becomes unresponsive.

A readiness probe determines whether a VM is ready to accept service requests. If the probe fails, the VM is removed from the list of available endpoints until the VM is ready.

A liveness probe determines whether a VM is responsive. If the probe fails, the VM is deleted and a new VM is created to restore responsiveness.

You can configure readiness and liveness probes by setting the spec.readinessProbe and the spec.livenessProbe fields of the VirtualMachine object. These fields support the following tests:

HTTP GET
The probe determines the health of the VM by using a web hook. The test is successful if the HTTP response code is between 200 and 399. You can use an HTTP GET test with applications that return HTTP status codes when they are completely initialized.
TCP socket
The probe attempts to open a socket to the VM. The VM is only considered healthy if the probe can establish a connection. You can use a TCP socket test with applications that do not start listening until initialization is complete.
Guest agent ping
The probe uses the guest-ping command to determine if the QEMU guest agent is running on the virtual machine.
12.6.1.1. Defining an HTTP readiness probe

Define an HTTP readiness probe by setting the spec.readinessProbe.httpGet field of the virtual machine (VM) configuration.

Procedure

  1. Include details of the readiness probe in the VM configuration file.

    Sample readiness probe with an HTTP GET test

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      annotations:
      name: fedora-vm
      namespace: example-namespace
    # ...
    spec:
      template:
        spec:
          readinessProbe:
            httpGet: 1
              port: 1500 2
              path: /healthz 3
              httpHeaders:
              - name: Custom-Header
                value: Awesome
            initialDelaySeconds: 120 4
            periodSeconds: 20 5
            timeoutSeconds: 10 6
            failureThreshold: 3 7
            successThreshold: 3 8
    # ...

    1
    The HTTP GET request to perform to connect to the VM.
    2
    The port of the VM that the probe queries. In the above example, the probe queries port 1500.
    3
    The path to access on the HTTP server. In the above example, if the handler for the server’s /healthz path returns a success code, the VM is considered to be healthy. If the handler returns a failure code, the VM is removed from the list of available endpoints.
    4
    The time, in seconds, after the VM starts before the readiness probe is initiated.
    5
    The delay, in seconds, between performing probes. The default delay is 10 seconds. This value must be greater than timeoutSeconds.
    6
    The number of seconds of inactivity after which the probe times out and the VM is assumed to have failed. The default value is 1. This value must be lower than periodSeconds.
    7
    The number of times that the probe is allowed to fail. The default is 3. After the specified number of attempts, the pod is marked Unready.
    8
    The number of times that the probe must report success, after a failure, to be considered successful. The default is 1.
  2. Create the VM by running the following command:

    $ oc create -f <file_name>.yaml
12.6.1.2. Defining a TCP readiness probe

Define a TCP readiness probe by setting the spec.readinessProbe.tcpSocket field of the virtual machine (VM) configuration.

Procedure

  1. Include details of the TCP readiness probe in the VM configuration file.

    Sample readiness probe with a TCP socket test

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      annotations:
      name: fedora-vm
      namespace: example-namespace
    # ...
    spec:
      template:
        spec:
          readinessProbe:
            initialDelaySeconds: 120 1
            periodSeconds: 20 2
            tcpSocket: 3
              port: 1500 4
            timeoutSeconds: 10 5
    # ...

    1
    The time, in seconds, after the VM starts before the readiness probe is initiated.
    2
    The delay, in seconds, between performing probes. The default delay is 10 seconds. This value must be greater than timeoutSeconds.
    3
    The TCP action to perform.
    4
    The port of the VM that the probe queries.
    5
    The number of seconds of inactivity after which the probe times out and the VM is assumed to have failed. The default value is 1. This value must be lower than periodSeconds.
  2. Create the VM by running the following command:

    $ oc create -f <file_name>.yaml
12.6.1.3. Defining an HTTP liveness probe

Define an HTTP liveness probe by setting the spec.livenessProbe.httpGet field of the virtual machine (VM) configuration. You can define both HTTP and TCP tests for liveness probes in the same way as readiness probes. This procedure configures a sample liveness probe with an HTTP GET test.

Procedure

  1. Include details of the HTTP liveness probe in the VM configuration file.

    Sample liveness probe with an HTTP GET test

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      annotations:
      name: fedora-vm
      namespace: example-namespace
    # ...
    spec:
      template:
        spec:
          livenessProbe:
            initialDelaySeconds: 120 1
            periodSeconds: 20 2
            httpGet: 3
              port: 1500 4
              path: /healthz 5
              httpHeaders:
              - name: Custom-Header
                value: Awesome
            timeoutSeconds: 10 6
    # ...

    1
    The time, in seconds, after the VM starts before the liveness probe is initiated.
    2
    The delay, in seconds, between performing probes. The default delay is 10 seconds. This value must be greater than timeoutSeconds.
    3
    The HTTP GET request to perform to connect to the VM.
    4
    The port of the VM that the probe queries. In the above example, the probe queries port 1500. The VM installs and runs a minimal HTTP server on port 1500 via cloud-init.
    5
    The path to access on the HTTP server. In the above example, if the handler for the server’s /healthz path returns a success code, the VM is considered to be healthy. If the handler returns a failure code, the VM is deleted and a new VM is created.
    6
    The number of seconds of inactivity after which the probe times out and the VM is assumed to have failed. The default value is 1. This value must be lower than periodSeconds.
  2. Create the VM by running the following command:

    $ oc create -f <file_name>.yaml

12.6.2. Defining a watchdog

You can define a watchdog to monitor the health of the guest operating system by performing the following steps:

  1. Configure a watchdog device for the virtual machine (VM).
  2. Install the watchdog agent on the guest.

The watchdog device monitors the agent and performs one of the following actions if the guest operating system is unresponsive:

  • poweroff: The VM powers down immediately. If spec.running is set to true or spec.runStrategy is not set to manual, then the VM reboots.
  • reset: The VM reboots in place and the guest operating system cannot react.

    Note

    The reboot time might cause liveness probes to time out. If cluster-level protections detect a failed liveness probe, the VM might be forcibly rescheduled, increasing the reboot time.

  • shutdown: The VM gracefully powers down by stopping all services.
Note

Watchdog is not available for Windows VMs.

12.6.2.1. Configuring a watchdog device for the virtual machine

You configure a watchdog device for the virtual machine (VM).

Prerequisites

  • The VM must have kernel support for an i6300esb watchdog device. Red Hat Enterprise Linux (RHEL) images support i6300esb.

Procedure

  1. Create a YAML file with the following contents:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      labels:
        kubevirt.io/vm: vm2-rhel84-watchdog
      name: <vm-name>
    spec:
      running: false
      template:
        metadata:
          labels:
            kubevirt.io/vm: vm2-rhel84-watchdog
        spec:
          domain:
            devices:
              watchdog:
                name: <watchdog>
                i6300esb:
                  action: "poweroff" 1
    # ...
    1
    Specify poweroff, reset, or shutdown.

    The example above configures the i6300esb watchdog device on a RHEL8 VM with the poweroff action and exposes the device as /dev/watchdog.

    This device can now be used by the watchdog binary.

  2. Apply the YAML file to your cluster by running the following command:

    $ oc apply -f <file_name>.yaml
Important

This procedure is provided for testing watchdog functionality only and must not be run on production machines.

  1. Run the following command to verify that the VM is connected to the watchdog device:

    $ lspci | grep watchdog -i
  2. Run one of the following commands to confirm the watchdog is active:

    • Trigger a kernel panic:

      # echo c > /proc/sysrq-trigger
    • Stop the watchdog service:

      # pkill -9 watchdog
12.6.2.2. Installing the watchdog agent on the guest

You install the watchdog agent on the guest and start the watchdog service.

Procedure

  1. Log in to the virtual machine as root user.
  2. Install the watchdog package and its dependencies:

    # yum install watchdog
  3. Uncomment the following line in the /etc/watchdog.conf file and save the changes:

    #watchdog-device = /dev/watchdog
  4. Enable the watchdog service to start on boot:

    # systemctl enable --now watchdog.service

12.6.3. Defining a guest agent ping probe

Define a guest agent ping probe by setting the spec.readinessProbe.guestAgentPing field of the virtual machine (VM) configuration.

Important

The guest agent ping probe is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

Prerequisites

  • The QEMU guest agent must be installed and enabled on the virtual machine.

Procedure

  1. Include details of the guest agent ping probe in the VM configuration file. For example:

    Sample guest agent ping probe

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      annotations:
      name: fedora-vm
      namespace: example-namespace
    # ...
    spec:
      template:
        spec:
          readinessProbe:
            guestAgentPing: {} 1
            initialDelaySeconds: 120 2
            periodSeconds: 20 3
            timeoutSeconds: 10 4
            failureThreshold: 3 5
            successThreshold: 3 6
    # ...

    1
    The guest agent ping probe to connect to the VM.
    2
    Optional: The time, in seconds, after the VM starts before the guest agent probe is initiated.
    3
    Optional: The delay, in seconds, between performing probes. The default delay is 10 seconds. This value must be greater than timeoutSeconds.
    4
    Optional: The number of seconds of inactivity after which the probe times out and the VM is assumed to have failed. The default value is 1. This value must be lower than periodSeconds.
    5
    Optional: The number of times that the probe is allowed to fail. The default is 3. After the specified number of attempts, the pod is marked Unready.
    6
    Optional: The number of times that the probe must report success, after a failure, to be considered successful. The default is 1.
  2. Create the VM by running the following command:

    $ oc create -f <file_name>.yaml

12.6.4. Additional resources

12.7. OpenShift Virtualization runbooks

To diagnose and resolve issues that trigger OpenShift Virtualization alerts, follow the procedures in the runbooks for the OpenShift Virtualization Operator. Triggered OpenShift Virtualization alerts can be viewed in the main ObserveAlerts tab in the web console, and also in the VirtualizationOverview tab.

Runbooks for the OpenShift Virtualization Operator are maintained in the openshift/runbooks Git repository, and you can view them on GitHub.

12.7.1. CDIDataImportCronOutdated

12.7.2. CDIDataVolumeUnusualRestartCount

12.7.3. CDIDefaultStorageClassDegraded

12.7.4. CDIMultipleDefaultVirtStorageClasses

12.7.5. CDINoDefaultStorageClass

12.7.6. CDINotReady

12.7.7. CDIOperatorDown

12.7.8. CDIStorageProfilesIncomplete

12.7.9. CnaoDown

12.7.10. CnaoNMstateMigration

12.7.11. HCOInstallationIncomplete

12.7.12. HPPNotReady

12.7.13. HPPOperatorDown

12.7.14. HPPSharingPoolPathWithOS

12.7.15. KubemacpoolDown

12.7.16. KubeMacPoolDuplicateMacsFound

12.7.17. KubeVirtComponentExceedsRequestedCPU

  • The KubeVirtComponentExceedsRequestedCPU alert is deprecated.

12.7.18. KubeVirtComponentExceedsRequestedMemory

  • The KubeVirtComponentExceedsRequestedMemory alert is deprecated.

12.7.19. KubeVirtCRModified

12.7.20. KubeVirtDeprecatedAPIRequested

12.7.21. KubeVirtNoAvailableNodesToRunVMs

12.7.22. KubevirtVmHighMemoryUsage

12.7.23. KubeVirtVMIExcessiveMigrations

12.7.24. LowKVMNodesCount

12.7.25. LowReadyVirtControllersCount

12.7.26. LowReadyVirtOperatorsCount

12.7.27. LowVirtAPICount

12.7.28. LowVirtControllersCount

12.7.29. LowVirtOperatorCount

12.7.30. NetworkAddonsConfigNotReady

12.7.31. NoLeadingVirtOperator

12.7.32. NoReadyVirtController

12.7.33. NoReadyVirtOperator

12.7.34. OrphanedVirtualMachineInstances

12.7.35. OutdatedVirtualMachineInstanceWorkloads

12.7.36. SingleStackIPv6Unsupported

12.7.37. SSPCommonTemplatesModificationReverted

12.7.38. SSPDown

12.7.39. SSPFailingToReconcile

12.7.40. SSPHighRateRejectedVms

12.7.41. SSPTemplateValidatorDown

12.7.42. SSPOperatorDown

12.7.43. UnsupportedHCOModification

12.7.44. VirtAPIDown

12.7.45. VirtApiRESTErrorsBurst

12.7.46. VirtApiRESTErrorsHigh

12.7.47. VirtControllerDown

12.7.48. VirtControllerRESTErrorsBurst

12.7.49. VirtControllerRESTErrorsHigh

12.7.50. VirtHandlerDaemonSetRolloutFailing

12.7.51. VirtHandlerRESTErrorsBurst

12.7.52. VirtHandlerRESTErrorsHigh

12.7.53. VirtOperatorDown

12.7.54. VirtOperatorRESTErrorsBurst

12.7.55. VirtOperatorRESTErrorsHigh

12.7.56. VirtualMachineCRCErrors

  • The runbook for the VirtualMachineCRCErrors alert is deprecated because the alert was renamed to VMStorageClassWarning.

12.7.57. VMCannotBeEvicted

12.7.58. VMStorageClassWarning

Chapter 13. Support

13.1. Support overview

You can request assistance from Red Hat Support, report bugs, collect data about your environment, and monitor the health of your cluster and virtual machines (VMs) with the following tools.

13.1.1. Opening support tickets

If you have encountered an issue that requires immediate assistance from Red Hat Support, you can submit a support case.

To report a bug, you can create a Jira issue directly.

13.1.1.1. Submitting a support case

To request support from Red Hat Support, follow the instructions for submitting a support case.

It is helpful to collect debugging data to include with your support request.

13.1.1.1.1. Collecting data for Red Hat Support

You can gather debugging information by performing the following steps:

Collecting data about your environment
Configure Prometheus and Alertmanager and collect must-gather data for OpenShift Container Platform and OpenShift Virtualization.
must-gather tool for OpenShift Virtualization
Configure and use the must-gather tool.
Collecting data about VMs
Collect must-gather data and memory dumps from VMs.
13.1.1.2. Creating a Jira issue

To report a bug, you can create a Jira issue directly by filling out the form on the Create Issue page.

13.1.2. Web console monitoring

You can monitor the health of your cluster and VMs by using the OpenShift Container Platform web console. The web console displays resource usage, alerts, events, and trends for your cluster and for OpenShift Virtualization components and resources.

Table 13.1. Web console pages for monitoring and troubleshooting
PageDescription

Overview page

Cluster details, status, alerts, inventory, and resource usage

VirtualizationOverview tab

OpenShift Virtualization resources, usage, alerts, and status

VirtualizationTop consumers tab

Top consumers of CPU, memory, and storage

VirtualizationMigrations tab

Progress of live migrations

VirtualMachinesVirtualMachineVirtualMachine detailsMetrics tab

VM resource usage, storage, network, and migration

VirtualMachinesVirtualMachineVirtualMachine detailsEvents tab

List of VM events

VirtualMachinesVirtualMachineVirtualMachine detailsDiagnostics tab

VM status conditions and volume snapshot status

13.2. Collecting data for Red Hat Support

When you submit a support case to Red Hat Support, it is helpful to provide debugging information for OpenShift Container Platform and OpenShift Virtualization by using the following tools:

must-gather tool
The must-gather tool collects diagnostic information, including resource definitions and service logs.
Prometheus
Prometheus is a time-series database and a rule evaluation engine for metrics. Prometheus sends alerts to Alertmanager for processing.
Alertmanager
The Alertmanager service handles alerts received from Prometheus. The Alertmanager is also responsible for sending the alerts to external notification systems.

For information about the OpenShift Container Platform monitoring stack, see About OpenShift Container Platform monitoring.

13.2.1. Collecting data about your environment

Collecting data about your environment minimizes the time required to analyze and determine the root cause.

Prerequisites

13.2.2. Collecting data about virtual machines

Collecting data about malfunctioning virtual machines (VMs) minimizes the time required to analyze and determine the root cause.

Prerequisites

Procedure

  1. Collect must-gather data for the VMs using the /usr/bin/gather script.
  2. Collect screenshots of VMs that have crashed before you restart them.
  3. Collect memory dumps from VMs before remediation attempts.
  4. Record factors that the malfunctioning VMs have in common. For example, the VMs have the same host or network.

13.2.3. Using the must-gather tool for OpenShift Virtualization

You can collect data about OpenShift Virtualization resources by running the must-gather command with the OpenShift Virtualization image.

The default data collection includes information about the following resources:

  • OpenShift Virtualization Operator namespaces, including child objects
  • OpenShift Virtualization custom resource definitions
  • Namespaces that contain virtual machines
  • Basic virtual machine definitions

Instance types information is not currently collected by default; you can, however, run a command to optionally collect it.

Procedure

  • Run the following command to collect data about OpenShift Virtualization:

    $ oc adm must-gather \
      --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel9:v4.17.0 \
      -- /usr/bin/gather
13.2.3.1. must-gather tool options

You can run the oc adm must-gather command to collect must gather images for all the Operators and products deployed on your cluster without the need to explicitly specify the required images. Alternatively, you can specify a combination of scripts and environment variables for the following options:

  • Collecting detailed virtual machine (VM) information from a namespace
  • Collecting detailed information about specified VMs
  • Collecting image, image-stream, and image-stream-tags information
  • Limiting the maximum number of parallel processes used by the must-gather tool
13.2.3.1.1. Parameters

Environment variables

You can specify environment variables for a compatible script.

NS=<namespace_name>
Collect virtual machine information, including virt-launcher pod details, from the namespace that you specify. The VirtualMachine and VirtualMachineInstance CR data is collected for all namespaces.
VM=<vm_name>
Collect details about a particular virtual machine. To use this option, you must also specify a namespace by using the NS environment variable.
PROS=<number_of_processes>

Modify the maximum number of parallel processes that the must-gather tool uses. The default value is 5.

Important

Using too many parallel processes can cause performance issues. Increasing the maximum number of parallel processes is not recommended.

Scripts

Each script is compatible only with certain environment variable combinations.

/usr/bin/gather
Use the default must-gather script, which collects cluster data from all namespaces and includes only basic VM information. This script is compatible only with the PROS variable.
/usr/bin/gather --vms_details
Collect VM log files, VM definitions, control-plane logs, and namespaces that belong to OpenShift Virtualization resources. Specifying namespaces includes their child objects. If you use this parameter without specifying a namespace or VM, the must-gather tool collects this data for all VMs in the cluster. This script is compatible with all environment variables, but you must specify a namespace if you use the VM variable.
/usr/bin/gather --images
Collect image, image-stream, and image-stream-tags custom resource information. This script is compatible only with the PROS variable.
/usr/bin/gather --instancetypes
Collect instance types information. This information is not currently collected by default; you can, however, optionally collect it.
13.2.3.1.2. Usage and examples

Environment variables are optional. You can run a script by itself or with one or more compatible environment variables.

Table 13.2. Compatible parameters
ScriptCompatible environment variable

/usr/bin/gather

* PROS=<number_of_processes>

/usr/bin/gather --vms_details

* For a namespace: NS=<namespace_name>

* For a VM: VM=<vm_name> NS=<namespace_name>

* PROS=<number_of_processes>

/usr/bin/gather --images

* PROS=<number_of_processes>

Syntax

To collect must-gather logs for all Operators and products on your cluster in a single pass, run the following command:

$ oc adm must-gather --all-images

If you need to pass additional parameters to individual must-gather images, use the following command:

$ oc adm must-gather \
  --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel9:v4.17.0 \
  -- <environment_variable_1> <environment_variable_2> <script_name>

Default data collection parallel processes

By default, five processes run in parallel.

$ oc adm must-gather \
  --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel9:v4.17.0 \
  -- PROS=5 /usr/bin/gather 1
1
You can modify the number of parallel processes by changing the default.

Detailed VM information

The following command collects detailed VM information for the my-vm VM in the mynamespace namespace:

$ oc adm must-gather \
  --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel9:v4.17.0 \
  -- NS=mynamespace VM=my-vm /usr/bin/gather --vms_details 1
1
The NS environment variable is mandatory if you use the VM environment variable.

Image, image-stream, and image-stream-tags information

The following command collects image, image-stream, and image-stream-tags information from the cluster:

$ oc adm must-gather \
  --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel9:v4.17.0 \
  /usr/bin/gather --images

Instance types information

The following command collects instance types information from the cluster:

$ oc adm must-gather \
  --image=registry.redhat.io/container-native-virtualization/cnv-must-gather-rhel9:v4.17.0 \
  /usr/bin/gather --instancetypes

13.3. Troubleshooting

OpenShift Virtualization provides tools and logs for troubleshooting virtual machines (VMs) and virtualization components.

You can troubleshoot OpenShift Virtualization components by using the tools provided in the web console or by using the oc CLI tool.

13.3.1. Events

OpenShift Container Platform events are records of important life-cycle information and are useful for monitoring and troubleshooting virtual machine, namespace, and resource issues.

  • VM events: Navigate to the Events tab of the VirtualMachine details page in the web console.

    Namespace events

    You can view namespace events by running the following command:

    $ oc get events -n <namespace>

    See the list of events for details about specific events.

    Resource events

    You can view resource events by running the following command:

    $ oc describe <resource> <resource_name>

13.3.2. Pod logs

You can view logs for OpenShift Virtualization pods by using the web console or the CLI. You can also view aggregated logs by using the LokiStack in the web console.

13.3.2.1. Configuring OpenShift Virtualization pod log verbosity

You can configure the verbosity level of OpenShift Virtualization pod logs by editing the HyperConverged custom resource (CR).

Procedure

  1. To set log verbosity for specific components, open the HyperConverged CR in your default text editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Set the log level for one or more components by editing the spec.logVerbosityConfig stanza. For example:

    apiVersion: hco.kubevirt.io/v1beta1
    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      logVerbosityConfig:
        kubevirt:
          virtAPI: 5 1
          virtController: 4
          virtHandler: 3
          virtLauncher: 2
          virtOperator: 6
    1
    The log verbosity value must be an integer in the range 1–9, where a higher number indicates a more detailed log. In this example, the virtAPI component logs are exposed if their priority level is 5 or higher.
  3. Apply your changes by saving and exiting the editor.
13.3.2.2. Viewing virt-launcher pod logs with the web console

You can view the virt-launcher pod logs for a virtual machine by using the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. On the General tile, click the pod name to open the Pod details page.
  4. Click the Logs tab to view the logs.
13.3.2.3. Viewing OpenShift Virtualization pod logs with the CLI

You can view logs for the OpenShift Virtualization pods by using the oc CLI tool.

Procedure

  1. View a list of pods in the OpenShift Virtualization namespace by running the following command:

    $ oc get pods -n openshift-cnv

    Example 13.1. Example output

    NAME                               READY   STATUS    RESTARTS   AGE
    disks-images-provider-7gqbc        1/1     Running   0          32m
    disks-images-provider-vg4kx        1/1     Running   0          32m
    virt-api-57fcc4497b-7qfmc          1/1     Running   0          31m
    virt-api-57fcc4497b-tx9nc          1/1     Running   0          31m
    virt-controller-76c784655f-7fp6m   1/1     Running   0          30m
    virt-controller-76c784655f-f4pbd   1/1     Running   0          30m
    virt-handler-2m86x                 1/1     Running   0          30m
    virt-handler-9qs6z                 1/1     Running   0          30m
    virt-operator-7ccfdbf65f-q5snk     1/1     Running   0          32m
    virt-operator-7ccfdbf65f-vllz8     1/1     Running   0          32m
  2. View the pod log by running the following command:

    $ oc logs -n openshift-cnv <pod_name>
    Note

    If a pod fails to start, you can use the --previous option to view logs from the last attempt.

    To monitor log output in real time, use the -f option.

    Example 13.2. Example output

    {"component":"virt-handler","level":"info","msg":"set verbosity to 2","pos":"virt-handler.go:453","timestamp":"2022-04-17T08:58:37.373695Z"}
    {"component":"virt-handler","level":"info","msg":"set verbosity to 2","pos":"virt-handler.go:453","timestamp":"2022-04-17T08:58:37.373726Z"}
    {"component":"virt-handler","level":"info","msg":"setting rate limiter to 5 QPS and 10 Burst","pos":"virt-handler.go:462","timestamp":"2022-04-17T08:58:37.373782Z"}
    {"component":"virt-handler","level":"info","msg":"CPU features of a minimum baseline CPU model: map[apic:true clflush:true cmov:true cx16:true cx8:true de:true fpu:true fxsr:true lahf_lm:true lm:true mca:true mce:true mmx:true msr:true mtrr:true nx:true pae:true pat:true pge:true pni:true pse:true pse36:true sep:true sse:true sse2:true sse4.1:true ssse3:true syscall:true tsc:true]","pos":"cpu_plugin.go:96","timestamp":"2022-04-17T08:58:37.390221Z"}
    {"component":"virt-handler","level":"warning","msg":"host model mode is expected to contain only one model","pos":"cpu_plugin.go:103","timestamp":"2022-04-17T08:58:37.390263Z"}
    {"component":"virt-handler","level":"info","msg":"node-labeller is running","pos":"node_labeller.go:94","timestamp":"2022-04-17T08:58:37.391011Z"}

13.3.3. Guest system logs

Viewing the boot logs of VM guests can help diagnose issues. You can configure access to guests' logs and view them by using either the OpenShift Container Platform web console or the oc CLI.

This feature is disabled by default. If a VM does not explicitly have this setting enabled or disabled, it inherits the cluster-wide default setting.

Important

If sensitive information such as credentials or other personally identifiable information (PII) is written to the serial console, it is logged with all other visible text. Red Hat recommends using SSH to send sensitive data instead of the serial console.

13.3.3.1. Enabling default access to VM guest system logs with the web console

You can enable default access to VM guest system logs by using the web console.

Procedure

  1. From the side menu, click VirtualizationOverview.
  2. Click the Settings tab.
  3. Click ClusterGuest management.
  4. Set Enable guest system log access to on.
13.3.3.2. Enabling default access to VM guest system logs with the CLI

You can enable default access to VM guest system logs by editing the HyperConverged custom resource (CR).

Procedure

  1. Open the HyperConverged CR in your default editor by running the following command:

    $ oc edit hyperconverged kubevirt-hyperconverged -n openshift-cnv
  2. Update the disableSerialConsoleLog value. For example:

    kind: HyperConverged
    metadata:
      name: kubevirt-hyperconverged
    spec:
      virtualMachineOptions:
        disableSerialConsoleLog: true 1
    #...
    1
    Set the value of disableSerialConsoleLog to false if you want serial console access to be enabled on VMs by default.
13.3.3.3. Setting guest system log access for a single VM with the web console

You can configure access to VM guest system logs for a single VM by using the web console. This setting takes precedence over the cluster-wide default configuration.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. Click the Configuration tab.
  4. Set Guest system log access to on or off.
13.3.3.4. Setting guest system log access for a single VM with the CLI

You can configure access to VM guest system logs for a single VM by editing the VirtualMachine CR. This setting takes precedence over the cluster-wide default configuration.

Procedure

  1. Edit the virtual machine manifest by running the following command:

    $ oc edit vm <vm_name>
  2. Update the value of the logSerialConsole field. For example:

    apiVersion: kubevirt.io/v1
    kind: VirtualMachine
    metadata:
      name: example-vm
    spec:
      template:
        spec:
          domain:
            devices:
              logSerialConsole: true 1
    #...
    1
    To enable access to the guest’s serial console log, set the logSerialConsole value to true.
  3. Apply the new configuration to the VM by running the following command:

    $ oc apply vm <vm_name>
  4. Optional: If you edited a running VM, restart the VM to apply the new configuration. For example:

    $ virtctl restart <vm_name> -n <namespace>
13.3.3.5. Viewing guest system logs with the web console

You can view the serial console logs of a virtual machine (VM) guest by using the web console.

Prerequisites

  • Guest system log access is enabled.

Procedure

  1. Click VirtualizationVirtualMachines from the side menu.
  2. Select a virtual machine to open the VirtualMachine details page.
  3. Click the Diagnostics tab.
  4. Click Guest system logs to load the serial console.
13.3.3.6. Viewing guest system logs with the CLI

You can view the serial console logs of a VM guest by running the oc logs command.

Prerequisites

  • Guest system log access is enabled.

Procedure

  • View the logs by running the following command, substituting your own values for <namespace> and <vm_name>:

    $ oc logs -n <namespace> -l kubevirt.io/domain=<vm_name> --tail=-1 -c guest-console-log

13.3.4. Log aggregation

You can facilitate troubleshooting by aggregating and filtering logs.

13.3.4.1. Viewing aggregated OpenShift Virtualization logs with the LokiStack

You can view aggregated logs for OpenShift Virtualization pods and containers by using the LokiStack in the web console.

Prerequisites

  • You deployed the LokiStack.

Procedure

  1. Navigate to ObserveLogs in the web console.
  2. Select application, for virt-launcher pod logs, or infrastructure, for OpenShift Virtualization control plane pods and containers, from the log type list.
  3. Click Show Query to display the query field.
  4. Enter the LogQL query in the query field and click Run Query to display the filtered logs.
13.3.4.2. OpenShift Virtualization LogQL queries

You can view and filter aggregated logs for OpenShift Virtualization components by running Loki Query Language (LogQL) queries on the ObserveLogs page in the web console.

The default log type is infrastructure. The virt-launcher log type is application.

Optional: You can include or exclude strings or regular expressions by using line filter expressions.

Note

If the query matches a large number of logs, the query might time out.

Table 13.3. OpenShift Virtualization LogQL example queries
ComponentLogQL query

All

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"

cdi-apiserver

cdi-deployment

cdi-operator

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
|kubernetes_labels_app_kubernetes_io_component="storage"

hco-operator

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
|kubernetes_labels_app_kubernetes_io_component="deployment"

kubemacpool

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
|kubernetes_labels_app_kubernetes_io_component="network"

virt-api

virt-controller

virt-handler

virt-operator

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
|kubernetes_labels_app_kubernetes_io_component="compute"

ssp-operator

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
|kubernetes_labels_app_kubernetes_io_component="schedule"

Container

{log_type=~".+",kubernetes_container_name=~"<container>|<container>"} 1
|json|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
1
Specify one or more containers separated by a pipe (|).

virt-launcher

You must select application from the log type list before running this query.

{log_type=~".+", kubernetes_container_name="compute"}|json
|!= "custom-ga-command" 1
1
|!= "custom-ga-command" excludes libvirt logs that contain the string custom-ga-command. (BZ#2177684)

You can filter log lines to include or exclude strings or regular expressions by using line filter expressions.

Table 13.4. Line filter expressions
Line filter expressionDescription

|= "<string>"

Log line contains string

!= "<string>"

Log line does not contain string

|~ "<regex>"

Log line contains regular expression

!~ "<regex>"

Log line does not contain regular expression

Example line filter expression

{log_type=~".+"}|json
|kubernetes_labels_app_kubernetes_io_part_of="hyperconverged-cluster"
|= "error" != "timeout"

Additional resources for LokiStack and LogQL

  • xref :../../observability/logging/log_storage/about-log-storage.adoc#about-log-storage[About log storage]
  • LogQL log queries in the Grafana documentation

13.3.5. Common error messages

The following error messages might appear in OpenShift Virtualization logs:

ErrImagePull or ImagePullBackOff
Indicates an incorrect deployment configuration or problems with the images that are referenced.

13.3.6. Troubleshooting data volumes

You can check the Conditions and Events sections of the DataVolume object to analyze and resolve issues.

13.3.6.1. About data volume conditions and events

You can diagnose data volume issues by examining the output of the Conditions and Events sections generated by the command:

$ oc describe dv <DataVolume>

The Conditions section displays the following Types:

  • Bound
  • Running
  • Ready

The Events section provides the following additional information:

  • Type of event
  • Reason for logging
  • Source of the event
  • Message containing additional diagnostic information.

The output from oc describe does not always contains Events.

An event is generated when the Status, Reason, or Message changes. Both conditions and events react to changes in the state of the data volume.

For example, if you misspell the URL during an import operation, the import generates a 404 message. That message change generates an event with a reason. The output in the Conditions section is updated as well.

13.3.6.2. Analyzing data volume conditions and events

By inspecting the Conditions and Events sections generated by the describe command, you determine the state of the data volume in relation to persistent volume claims (PVCs), and whether or not an operation is actively running or completed. You might also receive messages that offer specific details about the status of the data volume, and how it came to be in its current state.

There are many different combinations of conditions. Each must be evaluated in its unique context.

Examples of various combinations follow.

  • Bound - A successfully bound PVC displays in this example.

    Note that the Type is Bound, so the Status is True. If the PVC is not bound, the Status is False.

    When the PVC is bound, an event is generated stating that the PVC is bound. In this case, the Reason is Bound and Status is True. The Message indicates which PVC owns the data volume.

    Message, in the Events section, provides further details including how long the PVC has been bound (Age) and by what resource (From), in this case datavolume-controller:

    Example output

    Status:
      Conditions:
        Last Heart Beat Time:  2020-07-15T03:58:24Z
        Last Transition Time:  2020-07-15T03:58:24Z
        Message:               PVC win10-rootdisk Bound
        Reason:                Bound
        Status:                True
        Type:                  Bound
    ...
      Events:
        Type     Reason     Age    From                   Message
        ----     ------     ----   ----                   -------
        Normal   Bound      24s    datavolume-controller  PVC example-dv Bound

  • Running - In this case, note that Type is Running and Status is False, indicating that an event has occurred that caused an attempted operation to fail, changing the Status from True to False.

    However, note that Reason is Completed and the Message field indicates Import Complete.

    In the Events section, the Reason and Message contain additional troubleshooting information about the failed operation. In this example, the Message displays an inability to connect due to a 404, listed in the Events section’s first Warning.

    From this information, you conclude that an import operation was running, creating contention for other operations that are attempting to access the data volume:

    Example output

    Status:
      Conditions:
        Last Heart Beat Time:  2020-07-15T04:31:39Z
        Last Transition Time:  2020-07-15T04:31:39Z
        Message:               Import Complete
        Reason:                Completed
        Status:                False
        Type:                  Running
    ...
      Events:
        Type     Reason       Age                From                   Message
        ----     ------       ----               ----                   -------
        Warning  Error        12s (x2 over 14s)  datavolume-controller  Unable to connect
        to http data source: expected status code 200, got 404. Status: 404 Not Found

  • Ready – If Type is Ready and Status is True, then the data volume is ready to be used, as in the following example. If the data volume is not ready to be used, the Status is False:

    Example output

    Status:
      Conditions:
        Last Heart Beat Time: 2020-07-15T04:31:39Z
        Last Transition Time:  2020-07-15T04:31:39Z
        Status:                True
        Type:                  Ready

Chapter 14. Backup and restore

14.1. Backup and restore by using VM snapshots

You can back up and restore virtual machines (VMs) by using snapshots. Snapshots are supported by the following storage providers:

  • Red Hat OpenShift Data Foundation
  • Any other cloud storage provider with the Container Storage Interface (CSI) driver that supports the Kubernetes Volume Snapshot API

Online snapshots have a default time deadline of five minutes (5m) that can be changed, if needed.

Important

Online snapshots are supported for virtual machines that have hot plugged virtual disks. However, hot plugged disks that are not in the virtual machine specification are not included in the snapshot.

To create snapshots of an online (Running state) VM with the highest integrity, install the QEMU guest agent if it is not included with your operating system. The QEMU guest agent is included with the default Red Hat templates.

The QEMU guest agent takes a consistent snapshot by attempting to quiesce the VM file system as much as possible, depending on the system workload. This ensures that in-flight I/O is written to the disk before the snapshot is taken. If the guest agent is not present, quiescing is not possible and a best-effort snapshot is taken. The conditions under which the snapshot was taken are reflected in the snapshot indications that are displayed in the web console or CLI.

14.1.1. About snapshots

A snapshot represents the state and data of a virtual machine (VM) at a specific point in time. You can use a snapshot to restore an existing VM to a previous state (represented by the snapshot) for backup and disaster recovery or to rapidly roll back to a previous development version.

A VM snapshot is created from a VM that is powered off (Stopped state) or powered on (Running state).

When taking a snapshot of a running VM, the controller checks that the QEMU guest agent is installed and running. If so, it freezes the VM file system before taking the snapshot, and thaws the file system after the snapshot is taken.

The snapshot stores a copy of each Container Storage Interface (CSI) volume attached to the VM and a copy of the VM specification and metadata. Snapshots cannot be changed after creation.

You can perform the following snapshot actions:

  • Create a new snapshot
  • Create a copy of a virtual machine from a snapshot
  • List all snapshots attached to a specific VM
  • Restore a VM from a snapshot
  • Delete an existing VM snapshot

VM snapshot controller and custom resources

The VM snapshot feature introduces three new API objects defined as custom resource definitions (CRDs) for managing snapshots:

  • VirtualMachineSnapshot: Represents a user request to create a snapshot. It contains information about the current state of the VM.
  • VirtualMachineSnapshotContent: Represents a provisioned resource on the cluster (a snapshot). It is created by the VM snapshot controller and contains references to all resources required to restore the VM.
  • VirtualMachineRestore: Represents a user request to restore a VM from a snapshot.

The VM snapshot controller binds a VirtualMachineSnapshotContent object with the VirtualMachineSnapshot object for which it was created, with a one-to-one mapping.

14.1.2. About application-consistent snapshots and backups

You can configure application-consistent snapshots and backups for Linux or Windows virtual machines (VMs) through a cycle of freezing and thawing. For any application, you can either configure a script on a Linux VM or register on a Windows VM to be notified when a snapshot or backup is due to begin.

On a Linux VM, freeze and thaw processes trigger automatically when a snapshot is taken or a backup is started by using, for example, a plugin from Velero or another backup vendor. The freeze process, performed by QEMU Guest Agent (QEMU GA) freeze hooks, ensures that before the snapshot or backup of a VM occurs, all of the VM’s filesystems are frozen and each appropriately configured application is informed that a snapshot or backup is about to start. This notification affords each application the opportunity to quiesce its state. Depending on the application, quiescing might involve temporarily refusing new requests, finishing in-progress operations, and flushing data to disk. The operating system is then directed to quiesce the filesystems by flushing outstanding writes to disk and freezing new write activity. All new connection requests are refused. When all applications have become inactive, the QEMU GA freezes the filesystems, and a snapshot is taken or a backup initiated. After the taking of the snapshot or start of the backup, the thawing process begins. Filesystems writing is reactivated and applications receive notification to resume normal operations.

The same cycle of freezing and thawing is available on a Windows VM. Applications register with the Volume Shadow Copy Service (VSS) to receive notifications that they should flush out their data because a backup or snapshot is imminent. Thawing of the applications after the backup or snapshot is complete returns them to an active state. For more details, see the Windows Server documentation about the Volume Shadow Copy Service.

14.1.3. Creating snapshots

You can create snapshots of virtual machines (VMs) by using the OpenShift Container Platform web console or the command line.

14.1.3.1. Creating a snapshot by using the web console

You can create a snapshot of a virtual machine (VM) by using the OpenShift Container Platform web console.

The VM snapshot includes disks that meet the following requirements:

  • Either a data volume or a persistent volume claim
  • Belong to a storage class that supports Container Storage Interface (CSI) volume snapshots

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. Click the Snapshots tab and then click Take Snapshot.
  4. Enter the snapshot name.
  5. Expand Disks included in this Snapshot to see the storage volumes to be included in the snapshot.
  6. If your VM has disks that cannot be included in the snapshot and you wish to proceed, select I am aware of this warning and wish to proceed.
  7. Click Save.
14.1.3.2. Creating a snapshot by using the command line

You can create a virtual machine (VM) snapshot for an offline or online VM by creating a VirtualMachineSnapshot object.

Prerequisites

  • Ensure that the persistent volume claims (PVCs) are in a storage class that supports Container Storage Interface (CSI) volume snapshots.
  • Install the OpenShift CLI (oc).
  • Optional: Power down the VM for which you want to create a snapshot.

Procedure

  1. Create a YAML file to define a VirtualMachineSnapshot object that specifies the name of the new VirtualMachineSnapshot and the name of the source VM as in the following example:

    apiVersion: snapshot.kubevirt.io/v1beta1
    kind: VirtualMachineSnapshot
    metadata:
      name: <snapshot_name>
    spec:
      source:
        apiGroup: kubevirt.io
        kind: VirtualMachine
        name: <vm_name>
  2. Create the VirtualMachineSnapshot object:

    $ oc create -f <snapshot_name>.yaml

    The snapshot controller creates a VirtualMachineSnapshotContent object, binds it to the VirtualMachineSnapshot, and updates the status and readyToUse fields of the VirtualMachineSnapshot object.

  3. Optional: If you are taking an online snapshot, you can use the wait command and monitor the status of the snapshot:

    1. Enter the following command:

      $ oc wait <vm_name> <snapshot_name> --for condition=Ready
    2. Verify the status of the snapshot:

      • InProgress - The online snapshot operation is still in progress.
      • Succeeded - The online snapshot operation completed successfully.
      • Failed - The online snapshot operaton failed.

        Note

        Online snapshots have a default time deadline of five minutes (5m). If the snapshot does not complete successfully in five minutes, the status is set to failed. Afterwards, the file system will be thawed and the VM unfrozen but the status remains failed until you delete the failed snapshot image.

        To change the default time deadline, add the FailureDeadline attribute to the VM snapshot spec with the time designated in minutes (m) or in seconds (s) that you want to specify before the snapshot operation times out.

        To set no deadline, you can specify 0, though this is generally not recommended, as it can result in an unresponsive VM.

        If you do not specify a unit of time such as m or s, the default is seconds (s).

Verification

  1. Verify that the VirtualMachineSnapshot object is created and bound with VirtualMachineSnapshotContent and that the readyToUse flag is set to true:

    $ oc describe vmsnapshot <snapshot_name>

    Example output

    apiVersion: snapshot.kubevirt.io/v1beta1
    kind: VirtualMachineSnapshot
    metadata:
      creationTimestamp: "2020-09-30T14:41:51Z"
      finalizers:
      - snapshot.kubevirt.io/vmsnapshot-protection
      generation: 5
      name: mysnap
      namespace: default
      resourceVersion: "3897"
      selfLink: /apis/snapshot.kubevirt.io/v1beta1/namespaces/default/virtualmachinesnapshots/my-vmsnapshot
      uid: 28eedf08-5d6a-42c1-969c-2eda58e2a78d
    spec:
      source:
        apiGroup: kubevirt.io
        kind: VirtualMachine
        name: my-vm
    status:
      conditions:
      - lastProbeTime: null
        lastTransitionTime: "2020-09-30T14:42:03Z"
        reason: Operation complete
        status: "False" 1
        type: Progressing
      - lastProbeTime: null
        lastTransitionTime: "2020-09-30T14:42:03Z"
        reason: Operation complete
        status: "True" 2
        type: Ready
      creationTime: "2020-09-30T14:42:03Z"
      readyToUse: true 3
      sourceUID: 355897f3-73a0-4ec4-83d3-3c2df9486f4f
      virtualMachineSnapshotContentName: vmsnapshot-content-28eedf08-5d6a-42c1-969c-2eda58e2a78d 4

    1
    The status field of the Progressing condition specifies if the snapshot is still being created.
    2
    The status field of the Ready condition specifies if the snapshot creation process is complete.
    3
    Specifies if the snapshot is ready to be used.
    4
    Specifies that the snapshot is bound to a VirtualMachineSnapshotContent object created by the snapshot controller.
  2. Check the spec:volumeBackups property of the VirtualMachineSnapshotContent resource to verify that the expected PVCs are included in the snapshot.

14.1.4. Verifying online snapshots by using snapshot indications

Snapshot indications are contextual information about online virtual machine (VM) snapshot operations. Indications are not available for offline virtual machine (VM) snapshot operations. Indications are helpful in describing details about the online snapshot creation.

Prerequisites

  • You must have attempted to create an online VM snapshot.

Procedure

  1. Display the output from the snapshot indications by performing one of the following actions:

    • Use the command line to view indicator output in the status stanza of the VirtualMachineSnapshot object YAML.
    • In the web console, click VirtualMachineSnapshotStatus in the Snapshot details screen.
  2. Verify the status of your online VM snapshot by viewing the values of the status.indications parameter:

    • Online indicates that the VM was running during online snapshot creation.
    • GuestAgent indicates that the QEMU guest agent was running during online snapshot creation.
    • NoGuestAgent indicates that the QEMU guest agent was not running during online snapshot creation. The QEMU guest agent could not be used to freeze and thaw the file system, either because the QEMU guest agent was not installed or running or due to another error.

14.1.5. Restoring virtual machines from snapshots

You can restore virtual machines (VMs) from snapshots by using the OpenShift Container Platform web console or the command line.

14.1.5.1. Restoring a VM from a snapshot by using the web console

You can restore a virtual machine (VM) to a previous configuration represented by a snapshot in the OpenShift Container Platform web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. If the VM is running, click the options menu kebab and select Stop to power it down.
  4. Click the Snapshots tab to view a list of snapshots associated with the VM.
  5. Select a snapshot to open the Snapshot Details screen.
  6. Click the options menu kebab and select Restore VirtualMachine from snapshot.
  7. Click Restore.
14.1.5.2. Restoring a VM from a snapshot by using the command line

You can restore an existing virtual machine (VM) to a previous configuration by using the command line. You can only restore from an offline VM snapshot.

Prerequisites

  • Power down the VM you want to restore.

Procedure

  1. Create a YAML file to define a VirtualMachineRestore object that specifies the name of the VM you want to restore and the name of the snapshot to be used as the source as in the following example:

    apiVersion: snapshot.kubevirt.io/v1beta1
    kind: VirtualMachineRestore
    metadata:
      name: <vm_restore>
    spec:
      target:
        apiGroup: kubevirt.io
        kind: VirtualMachine
        name: <vm_name>
      virtualMachineSnapshotName: <snapshot_name>
  2. Create the VirtualMachineRestore object:

    $ oc create -f <vm_restore>.yaml

    The snapshot controller updates the status fields of the VirtualMachineRestore object and replaces the existing VM configuration with the snapshot content.

Verification

  • Verify that the VM is restored to the previous state represented by the snapshot and that the complete flag is set to true:

    $ oc get vmrestore <vm_restore>

    Example output

    apiVersion: snapshot.kubevirt.io/v1beta1
    kind: VirtualMachineRestore
    metadata:
    creationTimestamp: "2020-09-30T14:46:27Z"
    generation: 5
    name: my-vmrestore
    namespace: default
    ownerReferences:
    - apiVersion: kubevirt.io/v1
      blockOwnerDeletion: true
      controller: true
      kind: VirtualMachine
      name: my-vm
      uid: 355897f3-73a0-4ec4-83d3-3c2df9486f4f
      resourceVersion: "5512"
      selfLink: /apis/snapshot.kubevirt.io/v1beta1/namespaces/default/virtualmachinerestores/my-vmrestore
      uid: 71c679a8-136e-46b0-b9b5-f57175a6a041
      spec:
        target:
          apiGroup: kubevirt.io
          kind: VirtualMachine
          name: my-vm
      virtualMachineSnapshotName: my-vmsnapshot
      status:
      complete: true 1
      conditions:
      - lastProbeTime: null
      lastTransitionTime: "2020-09-30T14:46:28Z"
      reason: Operation complete
      status: "False" 2
      type: Progressing
      - lastProbeTime: null
      lastTransitionTime: "2020-09-30T14:46:28Z"
      reason: Operation complete
      status: "True" 3
      type: Ready
      deletedDataVolumes:
      - test-dv1
      restoreTime: "2020-09-30T14:46:28Z"
      restores:
      - dataVolumeName: restore-71c679a8-136e-46b0-b9b5-f57175a6a041-datavolumedisk1
      persistentVolumeClaim: restore-71c679a8-136e-46b0-b9b5-f57175a6a041-datavolumedisk1
      volumeName: datavolumedisk1
      volumeSnapshotName: vmsnapshot-28eedf08-5d6a-42c1-969c-2eda58e2a78d-volume-datavolumedisk1

    1
    Specifies if the process of restoring the VM to the state represented by the snapshot is complete.
    2
    The status field of the Progressing condition specifies if the VM is still being restored.
    3
    The status field of the Ready condition specifies if the VM restoration process is complete.

14.1.6. Deleting snapshots

You can delete snapshots of virtual machines (VMs) by using the OpenShift Container Platform web console or the command line.

14.1.6.1. Deleting a snapshot by using the web console

You can delete an existing virtual machine (VM) snapshot by using the web console.

Procedure

  1. Navigate to VirtualizationVirtualMachines in the web console.
  2. Select a VM to open the VirtualMachine details page.
  3. Click the Snapshots tab to view a list of snapshots associated with the VM.
  4. Click the options menu kebab beside a snapshot and select Delete snapshot.
  5. Click Delete.
14.1.6.2. Deleting a virtual machine snapshot in the CLI

You can delete an existing virtual machine (VM) snapshot by deleting the appropriate VirtualMachineSnapshot object.

Prerequisites

  • Install the OpenShift CLI (oc).

Procedure

  • Delete the VirtualMachineSnapshot object:

    $ oc delete vmsnapshot <snapshot_name>

    The snapshot controller deletes the VirtualMachineSnapshot along with the associated VirtualMachineSnapshotContent object.

Verification

  • Verify that the snapshot is deleted and no longer attached to this VM:

    $ oc get vmsnapshot

14.1.7. Additional resources

14.2. Backing up and restoring virtual machines

Important

Red Hat supports using OpenShift Virtualization 4.14 or later with OADP 1.3.x or later.

OADP versions earlier than 1.3.0 are not supported for back up and restore of OpenShift Virtualization.

Back up and restore virtual machines by using the OpenShift API for Data Protection.

You can install the OpenShift API for Data Protection (OADP) with OpenShift Virtualization by installing the OADP Operator and configuring a backup location. You can then install the Data Protection Application.

Note

OpenShift API for Data Protection with OpenShift Virtualization supports the following backup and restore storage options:

  • Container Storage Interface (CSI) backups
  • Container Storage Interface (CSI) backups with DataMover

The following storage options are excluded:

  • File system backup and restore
  • Volume snapshot backup and restore

For more information, see Backing up applications with File System Backup: Kopia or Restic.

To install the OADP Operator in a restricted network environment, you must first disable the default OperatorHub sources and mirror the Operator catalog.

See Using Operator Lifecycle Manager in disconnected environments for details.

14.2.1. Installing and configuring OADP with OpenShift Virtualization

As a cluster administrator, you install OADP by installing the OADP Operator.

The latest version of the OADP Operator installs Velero 1.14.

Prerequisites

  • Access to the cluster as a user with the cluster-admin role.

Procedure

  1. Install the OADP Operator according to the instructions for your storage provider.
  2. Install the Data Protection Application (DPA) with the kubevirt and openshift OADP plugins.
  3. Back up virtual machines by creating a Backup custom resource (CR).

    Warning

    Red Hat support is limited to only the following options:

    • CSI backups
    • CSI backups with DataMover.

You restore the Backup CR by creating a Restore CR.

14.2.2. Installing the Data Protection Application

You install the Data Protection Application (DPA) by creating an instance of the DataProtectionApplication API.

Prerequisites

  • You must install the OADP Operator.
  • You must configure object storage as a backup location.
  • If you use snapshots to back up PVs, your cloud provider must support either a native snapshot API or Container Storage Interface (CSI) snapshots.
  • If the backup and snapshot locations use the same credentials, you must create a Secret with the default name, cloud-credentials.

    Note

    If you do not want to specify backup or snapshot locations during the installation, you can create a default Secret with an empty credentials-velero file. If there is no default Secret, the installation will fail.

Procedure

  1. Click OperatorsInstalled Operators and select the OADP Operator.
  2. Under Provided APIs, click Create instance in the DataProtectionApplication box.
  3. Click YAML View and update the parameters of the DataProtectionApplication manifest:

    apiVersion: oadp.openshift.io/v1alpha1
    kind: DataProtectionApplication
    metadata:
      name: <dpa_sample>
      namespace: openshift-adp 1
    spec:
      configuration:
        velero:
          defaultPlugins:
            - kubevirt 2
            - gcp 3
            - csi 4
            - openshift 5
          resourceTimeout: 10m 6
        nodeAgent: 7
          enable: true 8
          uploaderType: kopia 9
          podConfig:
            nodeSelector: <node_selector> 10
      backupLocations:
        - velero:
            provider: gcp 11
            default: true
            credential:
              key: cloud
              name: <default_secret> 12
            objectStorage:
              bucket: <bucket_name> 13
              prefix: <prefix> 14
    1
    The default namespace for OADP is openshift-adp. The namespace is a variable and is configurable.
    2
    The kubevirt plugin is mandatory for OpenShift Virtualization.
    3
    Specify the plugin for the backup provider, for example, gcp, if it exists.
    4
    The csi plugin is mandatory for backing up PVs with CSI snapshots. The csi plugin uses the Velero CSI beta snapshot APIs. You do not need to configure a snapshot location.
    5
    The openshift plugin is mandatory.
    6
    Specify how many minutes to wait for several Velero resources before timeout occurs, such as Velero CRD availability, volumeSnapshot deletion, and backup repository availability. The default is 10m.
    7
    The administrative agent that routes the administrative requests to servers.
    8
    Set this value to true if you want to enable nodeAgent and perform File System Backup.
    9
    Enter kopia as your uploader to use the Built-in DataMover. The nodeAgent deploys a daemon set, which means that the nodeAgent pods run on each working node. You can configure File System Backup by adding spec.defaultVolumesToFsBackup: true to the Backup CR.
    10
    Specify the nodes on which Kopia are available. By default, Kopia runs on all nodes.
    11
    Specify the backup provider.
    12
    Specify the correct default name for the Secret, for example, cloud-credentials-gcp, if you use a default plugin for the backup provider. If specifying a custom name, then the custom name is used for the backup location. If you do not specify a Secret name, the default name is used.
    13
    Specify a bucket as the backup storage location. If the bucket is not a dedicated bucket for Velero backups, you must specify a prefix.
    14
    Specify a prefix for Velero backups, for example, velero, if the bucket is used for multiple purposes.
  4. Click Create.

Verification

  1. Verify the installation by viewing the OpenShift API for Data Protection (OADP) resources by running the following command:

    $ oc get all -n openshift-adp

    Example output

    NAME                                                     READY   STATUS    RESTARTS   AGE
    pod/oadp-operator-controller-manager-67d9494d47-6l8z8    2/2     Running   0          2m8s
    pod/node-agent-9cq4q                                     1/1     Running   0          94s
    pod/node-agent-m4lts                                     1/1     Running   0          94s
    pod/node-agent-pv4kr                                     1/1     Running   0          95s
    pod/velero-588db7f655-n842v                              1/1     Running   0          95s
    
    NAME                                                       TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)    AGE
    service/oadp-operator-controller-manager-metrics-service   ClusterIP   172.30.70.140    <none>        8443/TCP   2m8s
    service/openshift-adp-velero-metrics-svc                   ClusterIP   172.30.10.0      <none>        8085/TCP   8h
    
    NAME                        DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR   AGE
    daemonset.apps/node-agent    3         3         3       3            3           <none>          96s
    
    NAME                                                READY   UP-TO-DATE   AVAILABLE   AGE
    deployment.apps/oadp-operator-controller-manager    1/1     1            1           2m9s
    deployment.apps/velero                              1/1     1            1           96s
    
    NAME                                                           DESIRED   CURRENT   READY   AGE
    replicaset.apps/oadp-operator-controller-manager-67d9494d47    1         1         1       2m9s
    replicaset.apps/velero-588db7f655                              1         1         1       96s

  2. Verify that the DataProtectionApplication (DPA) is reconciled by running the following command:

    $ oc get dpa dpa-sample -n openshift-adp -o jsonpath='{.status}'

    Example output

    {"conditions":[{"lastTransitionTime":"2023-10-27T01:23:57Z","message":"Reconcile complete","reason":"Complete","status":"True","type":"Reconciled"}]}

  3. Verify the type is set to Reconciled.
  4. Verify the backup storage location and confirm that the PHASE is Available by running the following command:

    $ oc get backupStorageLocation -n openshift-adp

    Example output

    NAME           PHASE       LAST VALIDATED   AGE     DEFAULT
    dpa-sample-1   Available   1s               3d16h   true

14.3. Disaster recovery

OpenShift Virtualization supports using disaster recovery (DR) solutions to ensure that your environment can recover after a site outage. To use these methods, you must plan your OpenShift Virtualization deployment in advance.

14.3.1. About disaster recovery methods

For an overview of disaster recovery (DR) concepts, architecture, and planning considerations, see the Red Hat OpenShift Virtualization disaster recovery guide in the Red Hat Knowledgebase.

The two primary DR methods for OpenShift Virtualization are Metropolitan Disaster Recovery (Metro-DR) and Regional-DR.

14.3.1.1. Metro-DR

Metro-DR uses synchronous replication. It writes to storage at both the primary and secondary sites so that the data is always synchronized between sites. Because the storage provider is responsible for ensuring that the synchronization succeeds, the environment must meet the throughput and latency requirements of the storage provider.

14.3.1.2. Regional-DR

Regional-DR uses asynchronous replication. The data in the primary site is synchronized with the secondary site at regular intervals. For this type of replication, you can have a higher latency connection between the primary and secondary sites.

Important

Regional-DR is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

14.3.2. Defining applications for disaster recovery

Define applications for disaster recovery by using VMs that Red Hat Advanced Cluster Management (RHACM) manages or discovers.

14.3.2.1. Best practices when defining an RHACM-managed VM

An RHACM-managed application that includes a VM must be created by using a GitOps workflow and by creating an RHACM application or ApplicationSet.

There are several actions you can take to improve your experience and chance of success when defining an RHACM-managed VM.

Use a PVC and populator to define storage for the VM

Because data volumes create persistent volume claims (PVCs) implicitly, data volumes and VMs with data volume templates do not fit as neatly into the GitOps model.

Use the import method when choosing a population source for your VM disk

Use the import method to work around limitations in Regional-DR that prevent you from protecting VMs that use cloned PVCs.

Select a RHEL image from the software catalog to use the import method. Red Hat recommends using a specific version of the image rather than a floating tag for consistent results. The KubeVirt community maintains container disks for other operating systems in a Quay repository.

Use pullMethod: node

Use the pod pullMethod: node when creating a data volume from a registry source to take advantage of the OpenShift Container Platform pull secret, which is required to pull container images from the Red Hat registry.

14.3.2.2. Best practices when defining an RHACM-discovered virtual machine

You can configure any VM in the cluster that is not an RHACM-managed application as an RHACM-discovered application. This includes VMs imported by using the Migration Toolkit for Virtualization (MTV), VMs created by using the OpenShift Virtualization web console, or VMs created by any other means, such as the CLI.

There are several actions you can take to improve your experience and chance of success when defining an RHACM-discovered VM.

Protect the VM when using MTV, the OpenShift Virtualization web console, or a custom VM

Because automatic labeling is not currently available, the application owner must manually label the components of the VM application when using MTV, the OpenShift Virtualization web console, or a custom VM.

After creating the VM, apply a common label to the following resources associated with the VM: VirtualMachine, DataVolume, PersistentVolumeClaim, Service, Route, Secret, and ConfigMap. Do not label virtual machine instances (VMIs) or pods since OpenShift Virtualization creates and manages these automatically.

Include more than the VirtualMachine object in the VM

Working VMs typically also contain data volumes, persistent volume claims (PVCs), services, routes, secrets, ConfigMap objects, and VirtualMachineSnapshot objects.

Include the VM as part of a larger logical application

This includes other pod-based workloads and VMs.

14.3.3. VM behavior during disaster recovery scenarios

VMs typically act similarly to pod-based workloads during both relocate and failover disaster recovery flows.

Relocate

Use relocate to move an application from the primary environment to the secondary environment when the primary environment is still accessible. During relocate, the VM is gracefully terminated, any unreplicated data is synchronized to the secondary environment, and the VM starts in the secondary environment.

Becauase the terminates gracefully, there is no data loss in this scenario. Therefore, the VM operating system does not need to perform crash recovery.

Failover

Use failover when there is a critical failure in the primary environment that makes it impractical or impossible to use relocation to move the workload to a secondary environment. When failover is executed, the storage is fenced from the primary environment, the I/O to the VM disks is abruptly halted, and the VM restarts in the secondary environment using the replicated data.

You should expect data loss due to failover. The extent of loss depends on whether you use Metro-DR, which uses synchronous replication, or Regional-DR, which uses asynchronous replication. Because Regional-DR uses snapshot-based replication intervals, the window of data loss is proportional to the replication interval length. When the VM restarts, the operating system might perform crash recovery.

14.3.4. Metro-DR for Red Hat OpenShift Data Foundation

OpenShift Virtualization supports the Metro-DR solution for OpenShift Data Foundation, which provides two-way synchronous data replication between managed OpenShift Virtualization clusters installed on primary and secondary sites. This solution combines Red Hat Advanced Cluster Management (RHACM), Red Hat Ceph Storage, and OpenShift Data Foundation components.

Use this solution during a site disaster to failover applications from the primary to the secondary site, and relocate the applications back to the primary site after restoring the disaster site.

This synchronous solution is only available to metropolitan distance data centers with a 10-millisecond latency or less.

For more information about using the Metro-DR solution for OpenShift Data Foundation with OpenShift Virtualization, see the Red Hat Knowledgebase or IBM’s OpenShift Data Foundation Metro-DR documentation.

Legal Notice

Copyright © 2024 Red Hat, Inc.

OpenShift documentation is licensed under the Apache License 2.0 (https://www.apache.org/licenses/LICENSE-2.0).

Modified versions must remove all Red Hat trademarks.

Portions adapted from https://github.com/kubernetes-incubator/service-catalog/ with modifications by Red Hat.

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