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Windows Container Support for OpenShift

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OpenShift Container Platform 4.12

Red Hat OpenShift for Windows Containers Guide

Red Hat OpenShift Documentation Team

Abstract

Red Hat OpenShift for Windows Containers provides built-in support for running Microsoft Windows Server containers on OpenShift Container Platform. This guide provides all the details.

Chapter 1. Red Hat OpenShift support for Windows Containers overview

Red Hat OpenShift support for Windows Containers is a feature providing the ability to run Windows compute nodes in an OpenShift Container Platform cluster. This is possible by using the Red Hat Windows Machine Config Operator (WMCO) to install and manage Windows nodes. With a Red Hat subscription, you can get support for running Windows workloads in OpenShift Container Platform. Windows instances deployed by the WMCO are configured with the containerd container runtime. For more information, see the release notes.

You can add Windows nodes either by creating a compute machine set or by specifying existing Bring-Your-Own-Host (BYOH) Window instances through a configuration map.

Note

Compute machine sets are not supported for bare metal or provider agnostic clusters.

For workloads including both Linux and Windows, OpenShift Container Platform allows you to deploy Windows workloads running on Windows Server containers while also providing traditional Linux workloads hosted on Red Hat Enterprise Linux CoreOS (RHCOS) or Red Hat Enterprise Linux (RHEL). For more information, see getting started with Windows container workloads.

You need the WMCO to run Windows workloads in your cluster. The WMCO orchestrates the process of deploying and managing Windows workloads on a cluster. For more information, see how to enable Windows container workloads.

You can create a Windows MachineSet object to create infrastructure Windows machine sets and related machines so that you can move supported Windows workloads to the new Windows machines. You can create a Windows MachineSet object on multiple platforms.

You can schedule Windows workloads to Windows compute nodes.

You can perform Windows Machine Config Operator upgrades to ensure that your Windows nodes have the latest updates.

You can remove a Windows node by deleting a specific machine.

You can use Bring-Your-Own-Host (BYOH) Windows instances to repurpose Windows Server VMs and bring them to OpenShift Container Platform. BYOH Windows instances benefit users who are looking to mitigate major disruptions in the event that a Windows server goes offline. You can use BYOH Windows instances as nodes on OpenShift Container Platform 4.8 and later versions.

You can disable Windows container workloads by performing the following:

  • Uninstalling the Windows Machine Config Operator
  • Deleting the Windows Machine Config Operator namespace

Chapter 2. Release notes

2.1. Red Hat OpenShift support for Windows Containers release notes

The release notes for Red Hat OpenShift for Windows Containers tracks the development of the Windows Machine Config Operator (WMCO), which provides all Windows container workload capabilities in OpenShift Container Platform.

2.1.1. Release notes for Red Hat Windows Machine Config Operator 7.2.2

This release of the WMCO provides a security update and bug fixes for running Windows compute nodes in an OpenShift Container Platform cluster. The components of the WMCO 7.2.2 were released in RHSA-2024:6734.

2.2. Release notes for past releases of the Windows Machine Config Operator

The following release notes are for previous versions of the Windows Machine Config Operator (WMCO).

For the current version, see Red Hat OpenShift support for Windows Containers release notes.

2.2.1. Release notes for Red Hat Windows Machine Config Operator 7.2.1

This release of the WMCO provides new features and bug fixes for running Windows compute nodes in an OpenShift Container Platform cluster. The components of the WMCO 7.2.1 were released in RHBA-2024:1476.

2.2.1.1. Bug fixes
  • Previously, the WMCO did not properly wait for Windows virtual machines (VMs) to finish rebooting. This led to occasional timing issues where the WMCO would attempt to interact with a node that was in the middle of a reboot, causing WMCO to log an error and restart node configuration. Now, the WMCO waits for the instance to completely reboot. (OCPBUGS-23036)
  • Previously, the WMCO configuration was missing the DeleteEmptyDirData: true field, which is required for draining nodes that have emptyDir volumes attached. As a consequence, customers that had nodes with emptyDir volumes would see the following error in the logs: cannot delete Pods with local storage. With this fix, the DeleteEmptyDirData: true field was added to the node drain helper struct in the WMCO. As a result, customers are able to drain nodes with emptyDir volumes attached. (OCPBUGS-23081)
  • Previously, because of bad logic in the networking configuration script, the WICD was incorrectly reading carriage returns in the CNI configuration file as changes, and identified the file as modified. This caused the CNI configuration to be unnecessarily reloaded, potentially resulting in container restarts and brief network outages. With this fix, the WICD now reloads the CNI configuration only when the CNI configuration is actually modified. (OCPBUGS-27771)
  • Previously, the WMCO incorrectly approved the node certificate signing requests (CSR) for all nodes trying to join a cluster, not just Windows node CSRs. With this fix, the WMCO approves CSRs for only Windows nodes as expected. (OCPBUGS-27139)
  • Previously, because of routing issues present in Windows Server 2019, under certain conditions and after more than one hour of running time, workloads on Windows Server 2019 could have experienced packet loss when communicating with other containers in the cluster. This fix enables Direct Server Return (DSR) routing within kube-proxy. As a result, DSR now causes request and response traffic to use a different network path, circumventing the bug within Windows Server 2019. (OCPBUGS-28254)
  • Previously, because the upgrade path from WMCO 6.x to WMCO 7.x included previously released versions, the WMCO would fail during the upgrade. With this fix, you can successfully upgrade from WMCO 6.x to WMCO 7.x. (OCPBUGS-27775)
  • Previously, because of a lack of synchronization between Windows compute machine set nodes and Bring-Your-Own-Host (BYOH) instances, during an update the compute machine set nodes and the BYOH instances could update simultaneously, which could have impacted running workloads. This fix introduces a locking mechanism so that compute machine set nodes and BYOH instances update individually. (OCPBUGS-23020)

2.2.2. Release notes for Red Hat Windows Machine Config Operator 7.1.0

This release of the WMCO provides new features and bug fixes for running Windows compute nodes in an OpenShift Container Platform cluster. The components of the WMCO 7.1.0 were released in RHSA-2023:4025.

Important

Due to a known issue, your OpenShift Container Platform cluster must be on version 4.12.3 or greater before updating the WMCO from version 7.0.1 to version 7.1.0. The update fails if the cluster is lower than version 4.12.3.

2.2.2.1. Bug fixes
  • Previously, the containerd container runtime reported an incorrect version on each Windows node because repository tags were not propagated to the build system. This configuration caused containerd to report its go build version as the version of each Windows node. With this update, the correct version is injected into the binary during build time, so that containerd reports the correct version for each Windows node. (OCPBUGS-7843)
  • Previously, the Windows Machine Config Operator (WMCO) could not drain daemon set workloads. This issue caused Windows daemon set pods to block Windows nodes that the WMCO attempted to remove or update. With this update, the WMCO includes additional role-based access control (RBAC) permissions, so that the WMCO can remove daemon set workloads. The WMCO can also delete any processes that were created with the containerd shim, so that daemon set containers do not exist on a Windows instance after a WMCO removes a node from a cluster. (OCPBUGS-8056)
  • Previously, on an Azure Windows Server 2019 platform that does not have Azure container services installed, WMCO would fail to deploy Windows instances and would display the Install-WindowsFeature : Win32 internal error "Access is denied" 0x5 occurred while reading the console output buffer error message. The failure occurred because the Microsoft Install-WindowsFeature cmdlet displays a progress bar, which cannot be sent over an SSH connection. This fix hides the progress bar. As a result, Windows instances can be deployed as nodes. (OCPBUGS-14445)

2.2.3. Release notes for Red Hat Windows Machine Config Operator 7.0.1

This release of the WMCO provides new features and bug fixes for running Windows compute nodes in an OpenShift Container Platform cluster. The components of the WMCO 7.0.1 were released in RHBA-2023:0748.

2.2.3.1. Bug fixes
  • Previously, WMCO 7.0.0 did not support running in a namespace other than openshift-windows-machine-operator. With this fix, you can run WMCO in a custom namespace and can upgrade clusters that have WMCO installed in a custom namespace. (OCPBUGS-5065)

2.2.4. Release notes for Red Hat Windows Machine Config Operator 7.0.0

This release of the WMCO provides new features and bug fixes for running Windows compute nodes in an OpenShift Container Platform cluster. The components of the WMCO 7.0.0 were released in RHSA-2022:9096.

2.2.4.1. New features and improvements
2.2.4.1.1. Windows Instance Config Daemon (WICD)

The Windows Instance Config Daemon (WICD) is now performing many of the tasks that were previously performed by the Windows Machine Config Bootstrapper (WMCB). The WICD is installed on your Windows nodes. Users do not need to interact with the WICD and should not experience any difference in WMCO operation.

2.2.4.1.2. Support for clusters running on Google Cloud Platform

You can now run Windows Server 2022 nodes on a cluster installed on Google Cloud Platform (GCP). You can create a Windows MachineSet object on GCP to host Windows Server 2022 compute nodes. For more information, see Creating a Windows MachineSet object on vSphere.

2.2.4.2. Bug fixes
  • Previously, restarting the WMCO in a cluster with running Windows Nodes caused the windows exporter endpoint to be removed. Because of this, each Windows node could not report any metrics data. After this fix, the endpoint is retained when the WMCO is restarted. As a result, metrics data is reported properly after restarting WMCO. (BZ#2107261)
  • Previously, the test to determine if the Windows Defender antivirus service is running was incorrectly checking for any process whose name started with Windows Defender, regardless of state. This resulted in an error when creating firewall exclusions for containerd on instances without Windows Defender installed. This fix now checks for the presence of the specific running process associated with the Windows Defender antivirus service. As a result, the WMCO can properly configure Windows instances as nodes regardless of whether Windows Defender is installed or not. (OCPBUGS-3573)
2.2.4.3. Known issues

The following known limitations have been announced after the previous WMCO release:

  • OpenShift Serverless, Horizontal Pod Autoscaling, and Vertical Pod Autoscaling are not supported on Windows nodes.
  • Red Hat OpenShift support for Windows Containers does not support adding Windows nodes to a cluster through a trunk port. The only supported networking configuration for adding Windows nodes is through an access port that carries traffic for the VLAN.
  • WMCO 7.0.0 does not support running in a namespace other than openshift-windows-machine-operator. If you are using a custom namespace, it is recommended that you not upgrade to WMCO 7.0.0. Instead, you should upgrade to WMCO 7.0.1 when it is released. If your WMCO is configured with the Automatic update approval strategy, you should change it to Manual for WMCO 7.0.0. See the installation instructions for information on changing the approval strategy.

Additional resources

See the full list of known limitations

2.3. Windows Machine Config Operator prerequisites

The following information details the supported platform versions, Windows Server versions, and networking configurations for the Windows Machine Config Operator. See the vSphere documentation for any information that is relevant to only that platform.

2.3.1. WMCO 7.2.x supported platforms and Windows Server versions

The following table lists the Windows Server versions that are supported by WMCO 7.2.0 and 7.2.1, based on the applicable platform. Unlisted Windows Server versions are not supported and attempting to use them will cause errors.

PlatformSupported Windows Server version

Amazon Web Services (AWS)

  • Windows Server 2022, OS Build 20348.681 or later
  • Windows Server 2019, version 1809

Microsoft Azure

  • Windows Server 2022, OS Build 20348.681 or later
  • Windows Server 2019, version 1809

VMware vSphere

  • Windows Server 2022, OS Build 20348.681 or later

Google Cloud Platform (GCP)

  • Windows Server 2022, OS Build 20348.681 or later

Bare metal or provider agnostic

  • Windows Server 2022, OS Build 20348.681 or later
  • Windows Server 2019, version 1809

2.3.2. WMCO 7.0 and 7.1 supported platforms and Windows Server versions

The following table lists the Windows Server versions that are supported by WMCO 7.0.0, 7.0.1, and 7.1.0, based on the applicable platform. Unlisted Windows Server versions are not supported and attempting to use them will cause errors.

PlatformSupported Windows Server version

Amazon Web Services (AWS)

  • Windows Server 2019, version 1809

Microsoft Azure

  • Windows Server 2022, OS Build 20348.681 or later
  • Windows Server 2019, version 1809

VMware vSphere

  • Windows Server 2022, OS Build 20348.681 or later

Google Cloud Platform (GCP)

  • Windows Server 2022, OS Build 20348.681 or later

Bare metal or provider agnostic

  • Windows Server 2022, OS Build 20348.681 or later
  • Windows Server 2019, version 1809

2.4. Windows Machine Config Operator known limitations

Note the following limitations when working with Windows nodes managed by the WMCO (Windows nodes).

  • The following OpenShift Container Platform features are not supported on Windows nodes:

    • Image builds
    • OpenShift Pipelines
    • OpenShift Service Mesh
    • OpenShift monitoring of user-defined projects
    • OpenShift Serverless
    • Horizontal Pod Autoscaling
    • Vertical Pod Autoscaling

  • The following Red Hat features are not supported on Windows nodes:

  • Dual NIC is not supported on WMCO-managed Windows instances.
  • Windows nodes do not support workloads created by using deployment configs. You can use a deployment or other method to deploy workloads.
  • Windows nodes are not supported in clusters that use a cluster-wide proxy. This is because the WMCO is not able to route traffic through the proxy connection for the workloads.
  • Windows nodes are not supported in clusters that are in a disconnected environment.
  • Red Hat OpenShift support for Windows Containers does not support adding Windows nodes to a cluster through a trunk port. The only supported networking configuration for adding Windows nodes is through an access port that carries traffic for the VLAN.
  • Red Hat OpenShift support for Windows Containers supports only in-tree storage drivers for all cloud providers.
  • Red Hat OpenShift support for Windows Containers does not support any Windows operating system language other than English (United States).
  • Due to a limitation within the Windows operating system, clusterNetwork CIDR addresses of class E, such as 240.0.0.0, are not compatible with Windows nodes.

  • Kubernetes has identified the following node feature limitations :

    • Huge pages are not supported for Windows containers.
    • Privileged containers are not supported for Windows containers.
  • Kubernetes has identified several API compatibility issues.

Chapter 3. Getting support

Windows Container Support for Red Hat OpenShift is provided and available as an optional, installable component. Windows Container Support for Red Hat OpenShift is not part of the OpenShift Container Platform subscription. It requires an additional Red Hat subscription and is supported according to the Scope of coverage and Service level agreements.

You must have this separate subscription to receive support for Windows Container Support for Red Hat OpenShift. Without this additional Red Hat subscription, deploying Windows container workloads in production clusters is not supported. You can request support through the Red Hat Customer Portal.

For more information, see the Red Hat OpenShift Container Platform Life Cycle Policy document for Red Hat OpenShift support for Windows Containers.

If you do not have this additional Red Hat subscription, you can use the Community Windows Machine Config Operator, a distribution that lacks official support.

Chapter 4. Understanding Windows container workloads

Red Hat OpenShift support for Windows Containers provides built-in support for running Microsoft Windows Server containers on OpenShift Container Platform. For those that administer heterogeneous environments with a mix of Linux and Windows workloads, OpenShift Container Platform allows you to deploy Windows workloads running on Windows Server containers while also providing traditional Linux workloads hosted on Red Hat Enterprise Linux CoreOS (RHCOS) or Red Hat Enterprise Linux (RHEL).

Note

Multi-tenancy for clusters that have Windows nodes is not supported. Clusters are considered multi-tenant when multiple workloads operate on shared infrastructure and resources. If one or more workloads running on an infrastructure cannot be trusted, the multi-tenant environment is considered hostile.

Hostile multi-tenant clusters introduce security concerns in all Kubernetes environments. Additional security features like pod security policies, or more fine-grained role-based access control (RBAC) for nodes, make exploiting your environment more difficult. However, if you choose to run hostile multi-tenant workloads, a hypervisor is the only security option you should use. The security domain for Kubernetes encompasses the entire cluster, not an individual node. For these types of hostile multi-tenant workloads, you should use physically isolated clusters.

Windows Server Containers provide resource isolation using a shared kernel but are not intended to be used in hostile multitenancy scenarios. Scenarios that involve hostile multitenancy should use Hyper-V Isolated Containers to strongly isolate tenants.

Additional resources

4.1. Windows workload management

To run Windows workloads in your cluster, you must first install the Windows Machine Config Operator (WMCO). The WMCO is a Linux-based Operator that runs on Linux-based control plane and compute nodes. The WMCO orchestrates the process of deploying and managing Windows workloads on a cluster.

Figure 4.1. WMCO design

WMCO workflow

Before deploying Windows workloads, you must create a Windows compute node and have it join the cluster. The Windows node hosts the Windows workloads in a cluster, and can run alongside other Linux-based compute nodes. You can create a Windows compute node by creating a Windows compute machine set to host Windows Server compute machines. You must apply a Windows-specific label to the compute machine set that specifies a Windows OS image.

The WMCO watches for machines with the Windows label. After a Windows compute machine set is detected and its respective machines are provisioned, the WMCO configures the underlying Windows virtual machine (VM) so that it can join the cluster as a compute node.

Figure 4.2. Mixed Windows and Linux workloads

Mixed Windows and Linux workloads

The WMCO expects a predetermined secret in its namespace containing a private key that is used to interact with the Windows instance. WMCO checks for this secret during boot up time and creates a user data secret which you must reference in the Windows MachineSet object that you created. Then the WMCO populates the user data secret with a public key that corresponds to the private key. With this data in place, the cluster can connect to the Windows VM using an SSH connection.

After the cluster establishes a connection with the Windows VM, you can manage the Windows node using similar practices as you would a Linux-based node.

Note

The OpenShift Container Platform web console provides most of the same monitoring capabilities for Windows nodes that are available for Linux nodes. However, the ability to monitor workload graphs for pods running on Windows nodes is not available at this time.

Scheduling Windows workloads to a Windows node can be done with typical pod scheduling practices like taints, tolerations, and node selectors; alternatively, you can differentiate your Windows workloads from Linux workloads and other Windows-versioned workloads by using a RuntimeClass object.

4.2. Windows node services

The following Windows-specific services are installed on each Windows node:

ServiceDescription

kubelet

Registers the Windows node and manages its status.

Container Network Interface (CNI) plugins

Exposes networking for Windows nodes.

Windows Instance Config Daemon (WICD)

Maintains the state of all services running on the Windows instance to ensure the instance functions as a worker node.

Windows Exporter

Exports Prometheus metrics from Windows nodes

Kubernetes Cloud Controller Manager (CCM)

Interacts with the underlying Azure cloud platform.

hybrid-overlay

Creates the OpenShift Container Platform Host Network Service (HNS).

kube-proxy

Maintains network rules on nodes allowing outside communication.

containerd container runtime

Manages the complete container lifecycle.

Chapter 5. Enabling Windows container workloads

Before adding Windows workloads to your cluster, you must install the Windows Machine Config Operator (WMCO), which is available in the OpenShift Container Platform OperatorHub. The WMCO orchestrates the process of deploying and managing Windows workloads on a cluster.

Note

Dual NIC is not supported on WMCO-managed Windows instances.

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 installed your cluster using installer-provisioned infrastructure, or using user-provisioned infrastructure with the platform: none field set in your install-config.yaml file.
  • You have configured hybrid networking with OVN-Kubernetes for your cluster. This must be completed during the installation of your cluster. For more information, see Configuring hybrid networking.
  • You are running an OpenShift Container Platform cluster version 4.6.8 or later.
Note

Windows instances deployed by the WMCO are configured with the containerd container runtime. Because WMCO installs and manages the runtime, it is recommanded that you do not manually install containerd on nodes.

Additional resources

5.1. Installing the Windows Machine Config Operator

You can install the Windows Machine Config Operator using either the web console or OpenShift CLI (oc).

Note
  • The WMCO is not supported in clusters that use a cluster-wide proxy because the WMCO is not able to route traffic through the proxy connection for the workloads.
  • Due to a limitation within the Windows operating system, clusterNetwork CIDR addresses of class E, such as 240.0.0.0, are not compatible with Windows nodes.

5.1.1. Installing the Windows Machine Config Operator using the web console

You can use the OpenShift Container Platform web console to install the Windows Machine Config Operator (WMCO).

Note

Dual NIC is not supported on WMCO-managed Windows instances.

Procedure

  1. From the Administrator perspective in the OpenShift Container Platform web console, navigate to the Operators → OperatorHub page.
  2. Use the Filter by keyword box to search for Windows Machine Config Operator in the catalog. Click the Windows Machine Config Operator tile.
  3. Review the information about the Operator and click Install.

  4. On the Install Operator page:

    1. Select the stable channel as the Update Channel. The stable channel enables the latest stable release of the WMCO to be installed.
    2. The Installation Mode is preconfigured because the WMCO must be available in a single namespace only.
    3. Choose the Installed Namespace for the WMCO. The default Operator recommended namespace is openshift-windows-machine-config-operator.
    4. Click the Enable Operator recommended cluster monitoring on the Namespace checkbox to enable cluster monitoring for the WMCO.

    5. Select an Approval Strategy.

      • The Automatic strategy allows Operator Lifecycle Manager (OLM) to automatically update the Operator when a new version is available.
      • The Manual strategy requires a user with appropriate credentials to approve the Operator update.

  1. Click Install. The WMCO is now listed on the Installed Operators page.

    Note

    The WMCO is installed automatically into the namespace you defined, like openshift-windows-machine-config-operator.

  2. Verify that the Status shows Succeeded to confirm successful installation of the WMCO.

5.1.2. Installing the Windows Machine Config Operator using the CLI

You can use the OpenShift CLI (oc) to install the Windows Machine Config Operator (WMCO).

Note

Dual NIC is not supported on WMCO-managed Windows instances.

Procedure

  1. Create a namespace for the WMCO.

    1. Create a Namespace object YAML file for the WMCO. For example, wmco-namespace.yaml: 

      apiVersion: v1
kind: Namespace
metadata:
  name: openshift-windows-machine-config-operator 1
  labels:
    openshift.io/cluster-monitoring: "true" 2
      1
      It is recommended to deploy the WMCO in the openshift-windows-machine-config-operator namespace.
      2
      This label is required for enabling cluster monitoring for the WMCO.

    2. Create the namespace: 

      $ oc create -f <file-name>.yaml

      For example: 

      $ oc create -f wmco-namespace.yaml

  2. Create the Operator group for the WMCO.

    1. Create an OperatorGroup object YAML file. For example, wmco-og.yaml: 

      apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: windows-machine-config-operator
  namespace: openshift-windows-machine-config-operator
spec:
  targetNamespaces:
  - openshift-windows-machine-config-operator

    2. Create the Operator group: 

      $ oc create -f <file-name>.yaml

      For example: 

      $ oc create -f wmco-og.yaml

  3. Subscribe the namespace to the WMCO.

    1. Create a Subscription object YAML file. For example, wmco-sub.yaml: 

      apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: windows-machine-config-operator
  namespace: openshift-windows-machine-config-operator
spec:
  channel: "stable" 1
  installPlanApproval: "Automatic" 2
  name: "windows-machine-config-operator"
  source: "redhat-operators" 3
  sourceNamespace: "openshift-marketplace" 4
      1
      Specify stable as the channel.
      2
      Set an approval strategy. You can set Automatic or Manual.
      3
      Specify the redhat-operators catalog source, which contains the windows-machine-config-operator package manifests. If your OpenShift Container Platform is installed on a restricted network, also known as a disconnected cluster, specify the name of the CatalogSource object you created when you configured the Operator LifeCycle Manager (OLM).
      4
      Namespace of the catalog source. Use openshift-marketplace for the default OperatorHub catalog sources.

    2. Create the subscription: 

      $ oc create -f <file-name>.yaml

      For example: 

      $ oc create -f wmco-sub.yaml

      The WMCO is now installed to the openshift-windows-machine-config-operator.

  4. Verify the WMCO installation: 

    $ oc get csv -n openshift-windows-machine-config-operator

    Example output

    NAME                                    DISPLAY                           VERSION   REPLACES   PHASE
windows-machine-config-operator.2.0.0   Windows Machine Config Operator   2.0.0                Succeeded

5.2. Configuring a secret for the Windows Machine Config Operator

To run the Windows Machine Config Operator (WMCO), you must create a secret in the WMCO namespace containing a private key. This is required to allow the WMCO to communicate with the Windows virtual machine (VM).

Prerequisites

  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).
  • You created a PEM-encoded file containing an RSA key.

Procedure

  • Define the secret required to access the Windows VMs: 

    $ oc create secret generic cloud-private-key --from-file=private-key.pem=${HOME}/.ssh/<key> \
    -n openshift-windows-machine-config-operator 1
1
You must create the private key in the WMCO namespace, like openshift-windows-machine-config-operator.

It is recommended to use a different private key than the one used when installing the cluster.

5.3. Using Windows containers in a proxy-enabled cluster

The Windows Machine Config Operator (WMCO) can consume and use a cluster-wide egress proxy configuration when making external requests outside the cluster’s internal network.

This allows you to add Windows nodes and run workloads in a proxy-enabled cluster, allowing your Windows nodes to pull images from registries that are secured behind your proxy server or to make requests to off-cluster services and services that use a custom public key infrastructure.

Note

The cluster-wide proxy affects system components only, not user workloads.

In proxy-enabled clusters, the WMCO is aware of the NO_PROXY, HTTP_PROXY, and HTTPS_PROXY values that are set for the cluster. The WMCO periodically checks whether the proxy environment variables have changed. If there is a discrepancy, the WMCO reconciles and updates the proxy environment variables on the Windows instances.

Windows workloads created on Windows nodes in proxy-enabled clusters do not inherit proxy settings from the node by default, the same as with Linux nodes. Also, by default PowerShell sessions do not inherit proxy settings on Windows nodes in proxy-enabled clusters.

Additional resources

5.4. Additional resources

Chapter 6. Creating Windows machine sets

6.1. Creating a Windows machine set on AWS

You can create a Windows MachineSet object to serve a specific purpose in your OpenShift Container Platform cluster on Amazon Web Services (AWS). For example, you might create infrastructure Windows machine sets and related machines so that you can move supporting Windows workloads to the new Windows machines.

Prerequisites
  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).

  • You are using a supported Windows Server as the operating system image.

    Use one of the following aws commands, as appropriate for your Windows Server release, to query valid AMI images:

    Example Windows Server 2022 command

    $ aws ec2 describe-images --region <aws_region_name> --filters "Name=name,Values=Windows_Server-2022*English*Core*Base*" "Name=is-public,Values=true" --query "reverse(sort_by(Images, &CreationDate))[*].{name: Name, id: ImageId}" --output table

    Example Windows Server 2019 command

    $ aws ec2 describe-images --region <aws_region_name> --filters "Name=name,Values=Windows_Server-2019*English*Core*Base*" "Name=is-public,Values=true" --query "reverse(sort_by(Images, &CreationDate))[*].{name: Name, id: ImageId}" --output table

    where:

    <aws_region_name>
    Specifies the name of your AWS region.

6.1.1. Machine API overview

The Machine API is a combination of primary resources that are based on the upstream Cluster API project and custom OpenShift Container Platform resources.

For OpenShift Container Platform 4.12 clusters, the Machine API performs all node host provisioning management actions after the cluster installation finishes. Because of this system, OpenShift Container Platform 4.12 offers an elastic, dynamic provisioning method on top of public or private cloud infrastructure.

The two primary resources are:

Machines
A fundamental unit that describes the host for a node. A machine has a providerSpec specification, which describes the types of compute nodes that are offered for different cloud platforms. For example, a machine type for a compute node might define a specific machine type and required metadata.
Machine sets

MachineSet resources are groups of compute machines. Compute machine sets are to compute machines as replica sets are to pods. If you need more compute machines or must scale them down, you change the replicas field on the MachineSet resource to meet your compute need.

Warning

Control plane machines cannot be managed by compute machine sets.

Control plane machine sets provide management capabilities for supported control plane machines that are similar to what compute machine sets provide for compute machines.

For more information, see “Managing control plane machines".

The following custom resources add more capabilities to your cluster:

Machine autoscaler

The MachineAutoscaler resource automatically scales compute machines in a cloud. You can set the minimum and maximum scaling boundaries for nodes in a specified compute machine set, and the machine autoscaler maintains that range of nodes.

The MachineAutoscaler object takes effect after a ClusterAutoscaler object exists. Both ClusterAutoscaler and MachineAutoscaler resources are made available by the ClusterAutoscalerOperator object.

Cluster autoscaler

This resource is based on the upstream cluster autoscaler project. In the OpenShift Container Platform implementation, it is integrated with the Machine API by extending the compute machine set API. You can use the cluster autoscaler to manage your cluster in the following ways:

  • Set cluster-wide scaling limits for resources such as cores, nodes, memory, and GPU
  • Set the priority so that the cluster prioritizes pods and new nodes are not brought online for less important pods
  • Set the scaling policy so that you can scale up nodes but not scale them down
Machine health check
The MachineHealthCheck resource detects when a machine is unhealthy, deletes it, and, on supported platforms, makes a new machine.

In OpenShift Container Platform version 3.11, you could not roll out a multi-zone architecture easily because the cluster did not manage machine provisioning. Beginning with OpenShift Container Platform version 4.1, this process is easier. Each compute machine set is scoped to a single zone, so the installation program sends out compute machine sets across availability zones on your behalf. And then because your compute is dynamic, and in the face of a zone failure, you always have a zone for when you must rebalance your machines. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability. The autoscaler provides best-effort balancing over the life of a cluster.

6.1.2. Sample YAML for a Windows MachineSet object on AWS

This sample YAML defines a Windows MachineSet object running on Amazon Web Services (AWS) that the Windows Machine Config Operator (WMCO) can react upon. 

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <infrastructure_id>-windows-worker-<zone> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id> 3
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-windows-worker-<zone> 4
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id> 5
        machine.openshift.io/cluster-api-machine-role: worker
        machine.openshift.io/cluster-api-machine-type: worker
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-windows-worker-<zone> 6
        machine.openshift.io/os-id: Windows 7
    spec:
      metadata:
        labels:
          node-role.kubernetes.io/worker: "" 8
      providerSpec:
        value:
          ami:
            id: <windows_container_ami> 9
          apiVersion: awsproviderconfig.openshift.io/v1beta1
          blockDevices:
            - ebs:
                iops: 0
                volumeSize: 120
                volumeType: gp2
          credentialsSecret:
            name: aws-cloud-credentials
          deviceIndex: 0
          iamInstanceProfile:
            id: <infrastructure_id>-worker-profile 10
          instanceType: m5a.large
          kind: AWSMachineProviderConfig
          placement:
            availabilityZone: <zone> 11
            region: <region> 12
          securityGroups:
            - filters:
                - name: tag:Name
                  values:
                    - <infrastructure_id>-worker-sg 13
          subnet:
            filters:
              - name: tag:Name
                values:
                  - <infrastructure_id>-private-<zone> 14
          tags:
            - name: kubernetes.io/cluster/<infrastructure_id> 15
              value: owned
          userDataSecret:
            name: windows-user-data 16
            namespace: openshift-machine-api
1 3 5 10 13 14 15
Specify the infrastructure ID that is based on the cluster ID that you set when you provisioned the cluster. You can obtain the infrastructure ID by running the following command: 
$ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster
2 4 6
Specify the infrastructure ID, worker label, and zone.
7
Configure the compute machine set as a Windows machine.
8
Configure the Windows node as a compute machine.
9
Specify the AMI ID of a supported Windows image with a container runtime installed.
11
Specify the AWS zone, like us-east-1a.
12
Specify the AWS region, like us-east-1.
16
Created by the WMCO when it is configuring the first Windows machine. After that, the windows-user-data is available for all subsequent compute machine sets to consume.

6.1.3. Creating a compute machine set

In addition to the compute machine sets created by the installation program, you can create your own to dynamically manage the machine compute resources for specific workloads of your choice.

Prerequisites

  • Deploy an OpenShift Container Platform cluster.
  • Install the OpenShift CLI (oc).
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. Create a new YAML file that contains the compute machine set custom resource (CR) sample and is named <file_name>.yaml.

    Ensure that you set the <clusterID> and <role> parameter values.

  2. Optional: If you are not sure which value to set for a specific field, you can check an existing compute machine set from your cluster.

    1. To list the compute machine sets in your cluster, run the following command: 

      $ oc get machinesets -n openshift-machine-api

      Example output

      NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1d   0         0                             55m
agl030519-vplxk-worker-us-east-1e   0         0                             55m
agl030519-vplxk-worker-us-east-1f   0         0                             55m

    2. To view values of a specific compute machine set custom resource (CR), run the following command: 

      $ oc get machineset <machineset_name> \
  -n openshift-machine-api -o yaml

      Example output

      apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <infrastructure_id>-<role> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id>
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id>
        machine.openshift.io/cluster-api-machine-role: <role>
        machine.openshift.io/cluster-api-machine-type: <role>
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
    spec:
      providerSpec: 3
        ...

      1
      The cluster infrastructure ID.
      2
      A default node label.
      Note

      For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra type machines.

      3
      The values in the <providerSpec> section of the compute machine set CR are platform-specific. For more information about <providerSpec> parameters in the CR, see the sample compute machine set CR configuration for your provider.

  3. Create a MachineSet CR by running the following command: 

    $ oc create -f <file_name>.yaml

Verification

  • View the list of compute machine sets by running the following command: 

    $ oc get machineset -n openshift-machine-api

    Example output

    NAME                                      DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-windows-worker-us-east-1a    1         1         1       1        11m
agl030519-vplxk-worker-us-east-1a            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1b            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1c            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1d            0         0                          55m
agl030519-vplxk-worker-us-east-1e            0         0                          55m
agl030519-vplxk-worker-us-east-1f            0         0                          55m

    When the new compute machine set is available, the DESIRED and CURRENT values match. If the compute machine set is not available, wait a few minutes and run the command again.

6.1.4. Additional resources

6.2. Creating a Windows machine set on Azure

You can create a Windows MachineSet object to serve a specific purpose in your OpenShift Container Platform cluster on Microsoft Azure. For example, you might create infrastructure Windows machine sets and related machines so that you can move supporting Windows workloads to the new Windows machines.

Prerequisites
  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).
  • You are using a supported Windows Server as the operating system image.

6.2.1. Machine API overview

The Machine API is a combination of primary resources that are based on the upstream Cluster API project and custom OpenShift Container Platform resources.

For OpenShift Container Platform 4.12 clusters, the Machine API performs all node host provisioning management actions after the cluster installation finishes. Because of this system, OpenShift Container Platform 4.12 offers an elastic, dynamic provisioning method on top of public or private cloud infrastructure.

The two primary resources are:

Machines
A fundamental unit that describes the host for a node. A machine has a providerSpec specification, which describes the types of compute nodes that are offered for different cloud platforms. For example, a machine type for a compute node might define a specific machine type and required metadata.
Machine sets

MachineSet resources are groups of compute machines. Compute machine sets are to compute machines as replica sets are to pods. If you need more compute machines or must scale them down, you change the replicas field on the MachineSet resource to meet your compute need.

Warning

Control plane machines cannot be managed by compute machine sets.

Control plane machine sets provide management capabilities for supported control plane machines that are similar to what compute machine sets provide for compute machines.

For more information, see “Managing control plane machines".

The following custom resources add more capabilities to your cluster:

Machine autoscaler

The MachineAutoscaler resource automatically scales compute machines in a cloud. You can set the minimum and maximum scaling boundaries for nodes in a specified compute machine set, and the machine autoscaler maintains that range of nodes.

The MachineAutoscaler object takes effect after a ClusterAutoscaler object exists. Both ClusterAutoscaler and MachineAutoscaler resources are made available by the ClusterAutoscalerOperator object.

Cluster autoscaler

This resource is based on the upstream cluster autoscaler project. In the OpenShift Container Platform implementation, it is integrated with the Machine API by extending the compute machine set API. You can use the cluster autoscaler to manage your cluster in the following ways:

  • Set cluster-wide scaling limits for resources such as cores, nodes, memory, and GPU
  • Set the priority so that the cluster prioritizes pods and new nodes are not brought online for less important pods
  • Set the scaling policy so that you can scale up nodes but not scale them down
Machine health check
The MachineHealthCheck resource detects when a machine is unhealthy, deletes it, and, on supported platforms, makes a new machine.

In OpenShift Container Platform version 3.11, you could not roll out a multi-zone architecture easily because the cluster did not manage machine provisioning. Beginning with OpenShift Container Platform version 4.1, this process is easier. Each compute machine set is scoped to a single zone, so the installation program sends out compute machine sets across availability zones on your behalf. And then because your compute is dynamic, and in the face of a zone failure, you always have a zone for when you must rebalance your machines. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability. The autoscaler provides best-effort balancing over the life of a cluster.

6.2.2. Sample YAML for a Windows MachineSet object on Azure

This sample YAML defines a Windows MachineSet object running on Microsoft Azure that the Windows Machine Config Operator (WMCO) can react upon. 

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <windows_machine_set_name> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id> 3
      machine.openshift.io/cluster-api-machineset: <windows_machine_set_name> 4
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id> 5
        machine.openshift.io/cluster-api-machine-role: worker
        machine.openshift.io/cluster-api-machine-type: worker
        machine.openshift.io/cluster-api-machineset: <windows_machine_set_name> 6
        machine.openshift.io/os-id: Windows 7
    spec:
      metadata:
        labels:
          node-role.kubernetes.io/worker: "" 8
      providerSpec:
        value:
          apiVersion: azureproviderconfig.openshift.io/v1beta1
          credentialsSecret:
            name: azure-cloud-credentials
            namespace: openshift-machine-api
          image: 9
            offer: WindowsServer
            publisher: MicrosoftWindowsServer
            resourceID: ""
            sku: 2019-Datacenter-with-Containers
            version: latest
          kind: AzureMachineProviderSpec
          location: <location> 10
          managedIdentity: <infrastructure_id>-identity 11
          networkResourceGroup: <infrastructure_id>-rg 12
          osDisk:
            diskSizeGB: 128
            managedDisk:
              storageAccountType: Premium_LRS
            osType: Windows
          publicIP: false
          resourceGroup: <infrastructure_id>-rg 13
          subnet: <infrastructure_id>-worker-subnet
          userDataSecret:
            name: windows-user-data 14
            namespace: openshift-machine-api
          vmSize: Standard_D2s_v3
          vnet: <infrastructure_id>-vnet 15
          zone: "<zone>" 16
1 3 5 11 12 13 15
Specify the infrastructure ID that is based on the cluster ID that you set when you provisioned the cluster. You can obtain the infrastructure ID by running the following command: 
$ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster
2 4 6
Specify the Windows compute machine set name. Windows machine names on Azure cannot be more than 15 characters long. Therefore, the compute machine set name cannot be more than 9 characters long, due to the way machine names are generated from it.
7
Configure the compute machine set as a Windows machine.
8
Configure the Windows node as a compute machine.
9
Specify a WindowsServer image offering that defines the 2019-Datacenter-with-Containers SKU.
10
Specify the Azure region, like centralus.
14
Created by the WMCO when it is configuring the first Windows machine. After that, the windows-user-data is available for all subsequent compute machine sets to consume.
16
Specify the zone within your region to place machines on. Be sure that your region supports the zone that you specify.

6.2.3. Creating a compute machine set

In addition to the compute machine sets created by the installation program, you can create your own to dynamically manage the machine compute resources for specific workloads of your choice.

Prerequisites

  • Deploy an OpenShift Container Platform cluster.
  • Install the OpenShift CLI (oc).
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. Create a new YAML file that contains the compute machine set custom resource (CR) sample and is named <file_name>.yaml.

    Ensure that you set the <clusterID> and <role> parameter values.

  2. Optional: If you are not sure which value to set for a specific field, you can check an existing compute machine set from your cluster.

    1. To list the compute machine sets in your cluster, run the following command: 

      $ oc get machinesets -n openshift-machine-api

      Example output

      NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1d   0         0                             55m
agl030519-vplxk-worker-us-east-1e   0         0                             55m
agl030519-vplxk-worker-us-east-1f   0         0                             55m

    2. To view values of a specific compute machine set custom resource (CR), run the following command: 

      $ oc get machineset <machineset_name> \
  -n openshift-machine-api -o yaml

      Example output

      apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <infrastructure_id>-<role> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id>
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id>
        machine.openshift.io/cluster-api-machine-role: <role>
        machine.openshift.io/cluster-api-machine-type: <role>
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
    spec:
      providerSpec: 3
        ...

      1
      The cluster infrastructure ID.
      2
      A default node label.
      Note

      For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra type machines.

      3
      The values in the <providerSpec> section of the compute machine set CR are platform-specific. For more information about <providerSpec> parameters in the CR, see the sample compute machine set CR configuration for your provider.

  3. Create a MachineSet CR by running the following command: 

    $ oc create -f <file_name>.yaml

Verification

  • View the list of compute machine sets by running the following command: 

    $ oc get machineset -n openshift-machine-api

    Example output

    NAME                                      DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-windows-worker-us-east-1a    1         1         1       1        11m
agl030519-vplxk-worker-us-east-1a            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1b            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1c            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1d            0         0                          55m
agl030519-vplxk-worker-us-east-1e            0         0                          55m
agl030519-vplxk-worker-us-east-1f            0         0                          55m

    When the new compute machine set is available, the DESIRED and CURRENT values match. If the compute machine set is not available, wait a few minutes and run the command again.

6.2.4. Additional resources

6.3. Creating a Windows machine set on vSphere

You can create a Windows MachineSet object to serve a specific purpose in your OpenShift Container Platform cluster on VMware vSphere. For example, you might create infrastructure Windows machine sets and related machines so that you can move supporting Windows workloads to the new Windows machines.

Prerequisites
  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).
  • You are using a supported Windows Server as the operating system image.

6.3.1. Machine API overview

The Machine API is a combination of primary resources that are based on the upstream Cluster API project and custom OpenShift Container Platform resources.

For OpenShift Container Platform 4.12 clusters, the Machine API performs all node host provisioning management actions after the cluster installation finishes. Because of this system, OpenShift Container Platform 4.12 offers an elastic, dynamic provisioning method on top of public or private cloud infrastructure.

The two primary resources are:

Machines
A fundamental unit that describes the host for a node. A machine has a providerSpec specification, which describes the types of compute nodes that are offered for different cloud platforms. For example, a machine type for a compute node might define a specific machine type and required metadata.
Machine sets

MachineSet resources are groups of compute machines. Compute machine sets are to compute machines as replica sets are to pods. If you need more compute machines or must scale them down, you change the replicas field on the MachineSet resource to meet your compute need.

Warning

Control plane machines cannot be managed by compute machine sets.

Control plane machine sets provide management capabilities for supported control plane machines that are similar to what compute machine sets provide for compute machines.

For more information, see “Managing control plane machines".

The following custom resources add more capabilities to your cluster:

Machine autoscaler

The MachineAutoscaler resource automatically scales compute machines in a cloud. You can set the minimum and maximum scaling boundaries for nodes in a specified compute machine set, and the machine autoscaler maintains that range of nodes.

The MachineAutoscaler object takes effect after a ClusterAutoscaler object exists. Both ClusterAutoscaler and MachineAutoscaler resources are made available by the ClusterAutoscalerOperator object.

Cluster autoscaler

This resource is based on the upstream cluster autoscaler project. In the OpenShift Container Platform implementation, it is integrated with the Machine API by extending the compute machine set API. You can use the cluster autoscaler to manage your cluster in the following ways:

  • Set cluster-wide scaling limits for resources such as cores, nodes, memory, and GPU
  • Set the priority so that the cluster prioritizes pods and new nodes are not brought online for less important pods
  • Set the scaling policy so that you can scale up nodes but not scale them down
Machine health check
The MachineHealthCheck resource detects when a machine is unhealthy, deletes it, and, on supported platforms, makes a new machine.

In OpenShift Container Platform version 3.11, you could not roll out a multi-zone architecture easily because the cluster did not manage machine provisioning. Beginning with OpenShift Container Platform version 4.1, this process is easier. Each compute machine set is scoped to a single zone, so the installation program sends out compute machine sets across availability zones on your behalf. And then because your compute is dynamic, and in the face of a zone failure, you always have a zone for when you must rebalance your machines. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability. The autoscaler provides best-effort balancing over the life of a cluster.

6.3.2. Preparing your vSphere environment for Windows container workloads

You must prepare your vSphere environment for Windows container workloads by creating the vSphere Windows VM golden image and enabling communication with the internal API server for the WMCO.

6.3.2.1. Creating the vSphere Windows VM golden image

Create a vSphere Windows virtual machine (VM) golden image.

Prerequisites

  • You have created a private/public key pair, which is used to configure key-based authentication in the OpenSSH server. The private key must also be configured in the Windows Machine Config Operator (WMCO) namespace. This is required to allow the WMCO to communicate with the Windows VM. See the "Configuring a secret for the Windows Machine Config Operator" section for more details.
Note

You must use Microsoft PowerShell commands in several cases when creating your Windows VM. PowerShell commands in this guide are distinguished by the PS C:\> prefix.

Procedure

  1. Select a compatible Windows Server version. Currently, the Windows Machine Config Operator (WMCO) stable version supports Windows Server 2022 Long-Term Servicing Channel with the OS-level container networking patch KB5012637.

  2. Create a new VM in the vSphere client using the VM golden image with a compatible Windows Server version. For more information about compatible versions, see the "Windows Machine Config Operator prerequisites" section of the "Red Hat OpenShift support for Windows Containers release notes."

    Important

    The virtual hardware version for your VM must meet the infrastructure requirements for OpenShift Container Platform. For more information, see the "VMware vSphere infrastructure requirements" section in the OpenShift Container Platform documentation. Also, you can refer to VMware’s documentation on virtual machine hardware versions.

  3. Install and configure VMware Tools version 11.0.6 or greater on the Windows VM. See the VMware Tools documentation for more information.

  4. After installing VMware Tools on the Windows VM, verify the following:

    1. The C:\ProgramData\VMware\VMware Tools\tools.conf file exists with the following entry: 

      exclude-nics=

      If the tools.conf file does not exist, create it with the exclude-nics option uncommented and set as an empty value.

      This entry ensures the cloned vNIC generated on the Windows VM by the hybrid-overlay is not ignored.

    2. The Windows VM has a valid IP address in vCenter: 

      C:\> ipconfig

    3. The VMTools Windows service is running: 

      PS C:\> Get-Service -Name VMTools | Select Status, StartType
  5. Install and configure the OpenSSH Server on the Windows VM. See Microsoft’s documentation on installing OpenSSH for more details.

  6. Set up SSH access for an administrative user. See Microsoft’s documentation on the Administrative user to do this.

    Important

    The public key used in the instructions must correspond to the private key you create later in the WMCO namespace that holds your secret. See the "Configuring a secret for the Windows Machine Config Operator" section for more details.

  7. You must create a new firewall rule in the Windows VM that allows incoming connections for container logs. Run the following PowerShell command to create the firewall rule on TCP port 10250: 

    PS C:\> New-NetFirewallRule -DisplayName "ContainerLogsPort" -LocalPort 10250 -Enabled True -Direction Inbound -Protocol TCP -Action Allow -EdgeTraversalPolicy Allow
  8. Clone the Windows VM so it is a reusable image. Follow the VMware documentation on how to clone an existing virtual machine for more details.

  9. In the cloned Windows VM, run the Windows Sysprep tool: 

    C:\> C:\Windows\System32\Sysprep\sysprep.exe /generalize /oobe /shutdown /unattend:<path_to_unattend.xml> 1
    1
    Specify the path to your unattend.xml file.
    Note

    There is a limit on how many times you can run the sysprep command on a Windows image. Consult Microsoft’s documentation for more information.

    An example unattend.xml is provided, which maintains all the changes needed for the WMCO. You must modify this example; it cannot be used directly.

    Example 6.1. Example unattend.xml

    <?xml version="1.0" encoding="UTF-8"?>
<unattend xmlns="urn:schemas-microsoft-com:unattend">
   <settings pass="specialize">
      <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-International-Core" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
         <InputLocale>0409:00000409</InputLocale>
         <SystemLocale>en-US</SystemLocale>
         <UILanguage>en-US</UILanguage>
         <UILanguageFallback>en-US</UILanguageFallback>
         <UserLocale>en-US</UserLocale>
      </component>
      <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Security-SPP-UX" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
         <SkipAutoActivation>true</SkipAutoActivation>
      </component>
      <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-SQMApi" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
         <CEIPEnabled>0</CEIPEnabled>
      </component>
      <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
         <ComputerName>winhost</ComputerName> 1
      </component>
   </settings>
   <settings pass="oobeSystem">
      <component xmlns:wcm="http://schemas.microsoft.com/WMIConfig/2002/State" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" name="Microsoft-Windows-Shell-Setup" processorArchitecture="amd64" publicKeyToken="31bf3856ad364e35" language="neutral" versionScope="nonSxS">
         <AutoLogon>
            <Enabled>false</Enabled> 2
         </AutoLogon>
         <OOBE>
            <HideEULAPage>true</HideEULAPage>
            <HideLocalAccountScreen>true</HideLocalAccountScreen>
            <HideOEMRegistrationScreen>true</HideOEMRegistrationScreen>
            <HideOnlineAccountScreens>true</HideOnlineAccountScreens>
            <HideWirelessSetupInOOBE>true</HideWirelessSetupInOOBE>
            <NetworkLocation>Work</NetworkLocation>
            <ProtectYourPC>1</ProtectYourPC>
            <SkipMachineOOBE>true</SkipMachineOOBE>
            <SkipUserOOBE>true</SkipUserOOBE>
         </OOBE>
         <RegisteredOrganization>Organization</RegisteredOrganization>
         <RegisteredOwner>Owner</RegisteredOwner>
         <DisableAutoDaylightTimeSet>false</DisableAutoDaylightTimeSet>
         <TimeZone>Eastern Standard Time</TimeZone>
         <UserAccounts>
            <AdministratorPassword>
               <Value>MyPassword</Value> 3
               <PlainText>true</PlainText>
            </AdministratorPassword>
         </UserAccounts>
      </component>
   </settings>
</unattend>
    1
    Specify the ComputerName, which must follow the Kubernetes' names specification. These specifications also apply to Guest OS customization performed on the resulting template while creating new VMs.
    2
    Disable the automatic logon to avoid the security issue of leaving an open terminal with Administrator privileges at boot. This is the default value and must not be changed.
    3
    Replace the MyPassword placeholder with the password for the Administrator account. This prevents the built-in Administrator account from having a blank password by default. Follow Microsoft’s best practices for choosing a password.

    After the Sysprep tool has completed, the Windows VM will power off. You must not use or power on this VM anymore.

  10. Convert the Windows VM to a template in vCenter.
6.3.2.1.1. Additional resources
6.3.2.2. Enabling communication with the internal API server for the WMCO on vSphere

The Windows Machine Config Operator (WMCO) downloads the Ignition config files from the internal API server endpoint. You must enable communication with the internal API server so that your Windows virtual machine (VM) can download the Ignition config files, and the kubelet on the configured VM can only communicate with the internal API server.

Prerequisites

  • You have installed a cluster on vSphere.

Procedure

  • Add a new DNS entry for api-int.<cluster_name>.<base_domain> that points to the external API server URL api.<cluster_name>.<base_domain>. This can be a CNAME or an additional A record.
Note

The external API endpoint was already created as part of the initial cluster installation on vSphere.

6.3.3. Sample YAML for a Windows MachineSet object on vSphere

This sample YAML defines a Windows MachineSet object running on VMware vSphere that the Windows Machine Config Operator (WMCO) can react upon. 

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <windows_machine_set_name> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id> 3
      machine.openshift.io/cluster-api-machineset: <windows_machine_set_name> 4
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id> 5
        machine.openshift.io/cluster-api-machine-role: worker
        machine.openshift.io/cluster-api-machine-type: worker
        machine.openshift.io/cluster-api-machineset: <windows_machine_set_name> 6
        machine.openshift.io/os-id: Windows 7
    spec:
      metadata:
        labels:
          node-role.kubernetes.io/worker: "" 8
      providerSpec:
        value:
          apiVersion: vsphereprovider.openshift.io/v1beta1
          credentialsSecret:
            name: vsphere-cloud-credentials
          diskGiB: 128 9
          kind: VSphereMachineProviderSpec
          memoryMiB: 16384
          network:
            devices:
            - networkName: "<vm_network_name>" 10
          numCPUs: 4
          numCoresPerSocket: 1
          snapshot: ""
          template: <windows_vm_template_name> 11
          userDataSecret:
            name: windows-user-data 12
          workspace:
             datacenter: <vcenter_datacenter_name> 13
             datastore: <vcenter_datastore_name> 14
             folder: <vcenter_vm_folder_path> 15
             resourcePool: <vsphere_resource_pool> 16
             server: <vcenter_server_ip> 17
1 3 5
Specify the infrastructure ID that is based on the cluster ID that you set when you provisioned the cluster. You can obtain the infrastructure ID by running the following command: 
$ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster
2 4 6
Specify the Windows compute machine set name. The compute machine set name cannot be more than 9 characters long, due to the way machine names are generated in vSphere.
7
Configure the compute machine set as a Windows machine.
8
Configure the Windows node as a compute machine.
9
Specify the size of the vSphere Virtual Machine Disk (VMDK).
Note

This parameter does not set the size of the Windows partition. You can resize the Windows partition by using the unattend.xml file or by creating the vSphere Windows virtual machine (VM) golden image with the required disk size.

10
Specify the vSphere VM network to deploy the compute machine set to. This VM network must be where other Linux compute machines reside in the cluster.
11
Specify the full path of the Windows vSphere VM template to use, such as golden-images/windows-server-template. The name must be unique.
Important

Do not specify the original VM template. The VM template must remain off and must be cloned for new Windows machines. Starting the VM template configures the VM template as a VM on the platform, which prevents it from being used as a template that compute machine sets can apply configurations to.

12
The windows-user-data is created by the WMCO when the first Windows machine is configured. After that, the windows-user-data is available for all subsequent compute machine sets to consume.
13
Specify the vCenter Datacenter to deploy the compute machine set on.
14
Specify the vCenter Datastore to deploy the compute machine set on.
15
Specify the path to the vSphere VM folder in vCenter, such as /dc1/vm/user-inst-5ddjd.
16
Optional: Specify the vSphere resource pool for your Windows VMs.
17
Specify the vCenter server IP or fully qualified domain name.

6.3.4. Creating a compute machine set

In addition to the compute machine sets created by the installation program, you can create your own to dynamically manage the machine compute resources for specific workloads of your choice.

Prerequisites

  • Deploy an OpenShift Container Platform cluster.
  • Install the OpenShift CLI (oc).
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. Create a new YAML file that contains the compute machine set custom resource (CR) sample and is named <file_name>.yaml.

    Ensure that you set the <clusterID> and <role> parameter values.

  2. Optional: If you are not sure which value to set for a specific field, you can check an existing compute machine set from your cluster.

    1. To list the compute machine sets in your cluster, run the following command: 

      $ oc get machinesets -n openshift-machine-api

      Example output

      NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1d   0         0                             55m
agl030519-vplxk-worker-us-east-1e   0         0                             55m
agl030519-vplxk-worker-us-east-1f   0         0                             55m

    2. To view values of a specific compute machine set custom resource (CR), run the following command: 

      $ oc get machineset <machineset_name> \
  -n openshift-machine-api -o yaml

      Example output

      apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <infrastructure_id>-<role> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id>
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id>
        machine.openshift.io/cluster-api-machine-role: <role>
        machine.openshift.io/cluster-api-machine-type: <role>
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
    spec:
      providerSpec: 3
        ...

      1
      The cluster infrastructure ID.
      2
      A default node label.
      Note

      For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra type machines.

      3
      The values in the <providerSpec> section of the compute machine set CR are platform-specific. For more information about <providerSpec> parameters in the CR, see the sample compute machine set CR configuration for your provider.

  3. Create a MachineSet CR by running the following command: 

    $ oc create -f <file_name>.yaml

Verification

  • View the list of compute machine sets by running the following command: 

    $ oc get machineset -n openshift-machine-api

    Example output

    NAME                                      DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-windows-worker-us-east-1a    1         1         1       1        11m
agl030519-vplxk-worker-us-east-1a            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1b            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1c            1         1         1       1        55m
agl030519-vplxk-worker-us-east-1d            0         0                          55m
agl030519-vplxk-worker-us-east-1e            0         0                          55m
agl030519-vplxk-worker-us-east-1f            0         0                          55m

    When the new compute machine set is available, the DESIRED and CURRENT values match. If the compute machine set is not available, wait a few minutes and run the command again.

6.3.5. Additional resources

6.4. Creating a Windows machine set on GCP

You can create a Windows MachineSet object to serve a specific purpose in your OpenShift Container Platform cluster on Google Cloud Platform (GCP). For example, you might create infrastructure Windows machine sets and related machines so that you can move supporting Windows workloads to the new Windows machines.

Prerequisites
  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).
  • You are using a supported Windows Server as the operating system image.

6.4.1. Machine API overview

The Machine API is a combination of primary resources that are based on the upstream Cluster API project and custom OpenShift Container Platform resources.

For OpenShift Container Platform 4.12 clusters, the Machine API performs all node host provisioning management actions after the cluster installation finishes. Because of this system, OpenShift Container Platform 4.12 offers an elastic, dynamic provisioning method on top of public or private cloud infrastructure.

The two primary resources are:

Machines
A fundamental unit that describes the host for a node. A machine has a providerSpec specification, which describes the types of compute nodes that are offered for different cloud platforms. For example, a machine type for a compute node might define a specific machine type and required metadata.
Machine sets

MachineSet resources are groups of compute machines. Compute machine sets are to compute machines as replica sets are to pods. If you need more compute machines or must scale them down, you change the replicas field on the MachineSet resource to meet your compute need.

Warning

Control plane machines cannot be managed by compute machine sets.

Control plane machine sets provide management capabilities for supported control plane machines that are similar to what compute machine sets provide for compute machines.

For more information, see “Managing control plane machines".

The following custom resources add more capabilities to your cluster:

Machine autoscaler

The MachineAutoscaler resource automatically scales compute machines in a cloud. You can set the minimum and maximum scaling boundaries for nodes in a specified compute machine set, and the machine autoscaler maintains that range of nodes.

The MachineAutoscaler object takes effect after a ClusterAutoscaler object exists. Both ClusterAutoscaler and MachineAutoscaler resources are made available by the ClusterAutoscalerOperator object.

Cluster autoscaler

This resource is based on the upstream cluster autoscaler project. In the OpenShift Container Platform implementation, it is integrated with the Machine API by extending the compute machine set API. You can use the cluster autoscaler to manage your cluster in the following ways:

  • Set cluster-wide scaling limits for resources such as cores, nodes, memory, and GPU
  • Set the priority so that the cluster prioritizes pods and new nodes are not brought online for less important pods
  • Set the scaling policy so that you can scale up nodes but not scale them down
Machine health check
The MachineHealthCheck resource detects when a machine is unhealthy, deletes it, and, on supported platforms, makes a new machine.

In OpenShift Container Platform version 3.11, you could not roll out a multi-zone architecture easily because the cluster did not manage machine provisioning. Beginning with OpenShift Container Platform version 4.1, this process is easier. Each compute machine set is scoped to a single zone, so the installation program sends out compute machine sets across availability zones on your behalf. And then because your compute is dynamic, and in the face of a zone failure, you always have a zone for when you must rebalance your machines. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability. The autoscaler provides best-effort balancing over the life of a cluster.

6.4.2. Sample YAML for a Windows MachineSet object on GCP

This sample YAML file defines a Windows MachineSet object running on Google Cloud Platform (GCP) that the Windows Machine Config Operator (WMCO) can use. 

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <infrastructure_id>-windows-worker-<zone_suffix> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id> 3
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-windows-worker-<zone_suffix> 4
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id> 5
        machine.openshift.io/cluster-api-machine-role: worker
        machine.openshift.io/cluster-api-machine-type: worker
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-windows-worker-<zone_suffix> 6
        machine.openshift.io/os-id: Windows 7
    spec:
      metadata:
        labels:
          node-role.kubernetes.io/worker: "" 8
      providerSpec:
        value:
          apiVersion: machine.openshift.io/v1beta1
          canIPForward: false
          credentialsSecret:
            name: gcp-cloud-credentials
          deletionProtection: false
          disks:
          - autoDelete: true
            boot: true
            image: <windows_server_image> 9
            sizeGb: 128
            type: pd-ssd
          kind: GCPMachineProviderSpec
          machineType: n1-standard-4
          networkInterfaces:
          - network: <infrastructure_id>-network 10
            subnetwork: <infrastructure_id>-worker-subnet
          projectID: <project_id> 11
          region: <region> 12
          serviceAccounts:
          - email: <infrastructure_id>-w@<project_id>.iam.gserviceaccount.com
            scopes:
            - https://www.googleapis.com/auth/cloud-platform
          tags:
          - <infrastructure_id>-worker
          userDataSecret:
            name: windows-user-data 13
          zone: <zone> 14
1 3 5 10
Specify the infrastructure ID that is based on the cluster ID that you set when you provisioned the cluster. You can obtain the infrastructure ID by running the following command: 
$ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster
2 4 6
Specify the infrastructure ID, worker label, and zone suffix (such as a).
7
Configure the machine set as a Windows machine.
8
Configure the Windows node as a compute machine.
9
Specify the full path to an image of a supported version of Windows Server.
11
Specify the GCP project that this cluster was created in.
12
Specify the GCP region, such as us-central1.
13
Created by the WMCO when it configures the first Windows machine. After that, the windows-user-data is available for all subsequent machine sets to consume.
14
Specify the zone within the chosen region, such as us-central1-a.

6.4.3. Creating a compute machine set

In addition to the compute machine sets created by the installation program, you can create your own to dynamically manage the machine compute resources for specific workloads of your choice.

Prerequisites

  • Deploy an OpenShift Container Platform cluster.
  • Install the OpenShift CLI (oc).
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. Create a new YAML file that contains the compute machine set custom resource (CR) sample and is named <file_name>.yaml.

    Ensure that you set the <clusterID> and <role> parameter values.

  2. Optional: If you are not sure which value to set for a specific field, you can check an existing compute machine set from your cluster.

    1. To list the compute machine sets in your cluster, run the following command: 

      $ oc get machinesets -n openshift-machine-api

      Example output

      NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1d   0         0                             55m
agl030519-vplxk-worker-us-east-1e   0         0                             55m
agl030519-vplxk-worker-us-east-1f   0         0                             55m

    2. To view values of a specific compute machine set custom resource (CR), run the following command: 

      $ oc get machineset <machineset_name> \
  -n openshift-machine-api -o yaml

      Example output

      apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 1
  name: <infrastructure_id>-<role> 2
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id>
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id>
        machine.openshift.io/cluster-api-machine-role: <role>
        machine.openshift.io/cluster-api-machine-type: <role>
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>
    spec:
      providerSpec: 3
        ...

      1
      The cluster infrastructure ID.
      2
      A default node label.
      Note

      For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra type machines.

      3
      The values in the <providerSpec> section of the compute machine set CR are platform-specific. For more information about <providerSpec> parameters in the CR, see the sample compute machine set CR configuration for your provider.

  3. Create a MachineSet CR by running the following command: 

    $ oc create -f <file_name>.yaml

Verification

  • View the list of compute machine sets by running the following command: 

    $ oc get machineset -n openshift-machine-api

    Example output

    NAME                                DESIRED   CURRENT   READY   AVAILABLE   AGE
agl030519-vplxk-infra-us-east-1a    1         1         1       1           11m
agl030519-vplxk-worker-us-east-1a   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1b   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1c   1         1         1       1           55m
agl030519-vplxk-worker-us-east-1d   0         0                             55m
agl030519-vplxk-worker-us-east-1e   0         0                             55m
agl030519-vplxk-worker-us-east-1f   0         0                             55m

    When the new compute machine set is available, the DESIRED and CURRENT values match. If the compute machine set is not available, wait a few minutes and run the command again.

6.4.4. Additional resources

Chapter 7. Scheduling Windows container workloads

You can schedule Windows workloads to Windows compute nodes.

Note

The WMCO is not supported in clusters that use a cluster-wide proxy because the WMCO is not able to route traffic through the proxy connection for the workloads.

Prerequisites

  • You installed the Windows Machine Config Operator (WMCO) using Operator Lifecycle Manager (OLM).
  • You are using a Windows container as the OS image.
  • You have created a Windows compute machine set.

7.1. Windows pod placement

Before deploying your Windows workloads to the cluster, you must configure your Windows node scheduling so pods are assigned correctly. Since you have a machine hosting your Windows node, it is managed the same as a Linux-based node. Likewise, scheduling a Windows pod to the appropriate Windows node is completed similarly, using mechanisms like taints, tolerations, and node selectors.

With multiple operating systems, and the ability to run multiple Windows OS variants in the same cluster, you must map your Windows pods to a base Windows OS variant by using a RuntimeClass object. For example, if you have multiple Windows nodes running on different Windows Server container versions, the cluster could schedule your Windows pods to an incompatible Windows OS variant. You must have RuntimeClass objects configured for each Windows OS variant on your cluster. Using a RuntimeClass object is also recommended if you have only one Windows OS variant available in your cluster.

For more information, see Microsoft’s documentation on Host and container version compatibility.

Important

The container base image must be the same Windows OS version and build number that is running on the node where the conainer is to be scheduled.

Also, if you upgrade the Windows nodes from one version to another, for example going from 20H2 to 2022, you must upgrade your container base image to match the new version. For more information, see Windows container version compatibility.

Additional resources

7.2. Creating a RuntimeClass object to encapsulate scheduling mechanisms

Using a RuntimeClass object simplifies the use of scheduling mechanisms like taints and tolerations; you deploy a runtime class that encapsulates your taints and tolerations and then apply it to your pods to schedule them to the appropriate node. Creating a runtime class is also necessary in clusters that support multiple operating system variants.

Procedure

  1. Create a RuntimeClass object YAML file. For example, runtime-class.yaml: 

    apiVersion: node.k8s.io/v1
kind: RuntimeClass
metadata:
  name: windows2019 1
handler: 'runhcs-wcow-process'
scheduling:
  nodeSelector: 2
    kubernetes.io/os: 'windows'
    kubernetes.io/arch: 'amd64'
    node.kubernetes.io/windows-build: '10.0.17763'
  tolerations: 3
  - effect: NoSchedule
    key: os
    operator: Equal
    value: "windows"
  - effect: NoSchedule
    key: os
    operator: Equal
    value: "Windows"
    1
    Specify the RuntimeClass object name, which is defined in the pods you want to be managed by this runtime class.
    2
    Specify labels that must be present on nodes that support this runtime class. Pods using this runtime class can only be scheduled to a node matched by this selector. The node selector of the runtime class is merged with the existing node selector of the pod. Any conflicts prevent the pod from being scheduled to the node.
    • For Windows 2019, specify the node.kubernetes.io/windows-build: '10.0.17763' label.
    • For Windows 2022, specify the node.kubernetes.io/windows-build: '10.0.20348' label.
    3
    Specify tolerations to append to pods, excluding duplicates, running with this runtime class during admission. This combines the set of nodes tolerated by the pod and the runtime class.

  2. Create the RuntimeClass object: 

    $ oc create -f <file-name>.yaml

    For example: 

    $ oc create -f runtime-class.yaml

  3. Apply the RuntimeClass object to your pod to ensure it is scheduled to the appropriate operating system variant: 

    apiVersion: v1
kind: Pod
metadata:
  name: my-windows-pod
spec:
  runtimeClassName: windows2019 1
# ...
    1
    Specify the runtime class to manage the scheduling of your pod.

7.3. Sample Windows container workload deployment

You can deploy Windows container workloads to your cluster once you have a Windows compute node available.

Note

This sample deployment is provided for reference only.

Example Service object

apiVersion: v1
kind: Service
metadata:
  name: win-webserver
  labels:
    app: win-webserver
spec:
  ports:
    # the port that this service should serve on
  - port: 80
    targetPort: 80
  selector:
    app: win-webserver
  type: LoadBalancer

Example Deployment object

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: win-webserver
  name: win-webserver
spec:
  selector:
    matchLabels:
      app: win-webserver
  replicas: 1
  template:
    metadata:
      labels:
        app: win-webserver
      name: win-webserver
    spec:
      containers:
      - name: windowswebserver
        image: mcr.microsoft.com/windows/servercore:ltsc2019 1
        imagePullPolicy: IfNotPresent
        command:
        - powershell.exe 2
        - -command
        - $listener = New-Object System.Net.HttpListener; $listener.Prefixes.Add('http://*:80/'); $listener.Start();Write-Host('Listening at http://*:80/'); while ($listener.IsListening) { $context = $listener.GetContext(); $response = $context.Response; $content='<html><body><H1>Red Hat OpenShift + Windows Container Workloads</H1></body></html>'; $buffer = [System.Text.Encoding]::UTF8.GetBytes($content); $response.ContentLength64 = $buffer.Length; $response.OutputStream.Write($buffer, 0, $buffer.Length); $response.Close(); };
        securityContext:
          runAsNonRoot: false
          windowsOptions:
            runAsUserName: "ContainerAdministrator"
      os:
        name: "windows"
      runtimeClassName: windows2019 3

1
Specify the container image to use: mcr.microsoft.com/powershell:<tag> or mcr.microsoft.com/windows/servercore:<tag>. The container image must match the Windows version running on the node.
  • For Windows 2019, use the ltsc2019 tag.
  • For Windows 2022, use the ltsc2022 tag.
2
Specify the commands to execute on the container.
  • For the mcr.microsoft.com/powershell:<tag> container image, you must define the command as pwsh.exe.
  • For the mcr.microsoft.com/windows/servercore:<tag> container image, you must define the command as powershell.exe.
3
Specify the runtime class you created for the Windows operating system variant on your cluster.

7.4. Scaling a compute machine set manually

To add or remove an instance of a machine in a compute machine set, you can manually scale the compute machine set.

This guidance is relevant to fully automated, installer-provisioned infrastructure installations. Customized, user-provisioned infrastructure installations do not have compute machine sets.

Prerequisites

  • Install an OpenShift Container Platform cluster and the oc command line.
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. View the compute machine sets that are in the cluster by running the following command: 

    $ oc get machinesets -n openshift-machine-api

    The compute machine sets are listed in the form of <clusterid>-worker-<aws-region-az>.

  2. View the compute machines that are in the cluster by running the following command: 

    $ oc get machine -n openshift-machine-api

  3. Set the annotation on the compute machine that you want to delete by running the following command: 

    $ oc annotate machine/<machine_name> -n openshift-machine-api machine.openshift.io/delete-machine="true"

  4. Scale the compute machine set by running one of the following commands: 

    $ oc scale --replicas=2 machineset <machineset> -n openshift-machine-api

    Or: 

    $ oc edit machineset <machineset> -n openshift-machine-api
    Tip

    You can alternatively apply the following YAML to scale the compute machine set: 

    apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  name: <machineset>
  namespace: openshift-machine-api
spec:
  replicas: 2

    You can scale the compute machine set up or down. It takes several minutes for the new machines to be available.

    Important

    By default, the machine controller tries to drain the node that is backed by the machine until it succeeds. In some situations, such as with a misconfigured pod disruption budget, the drain operation might not be able to succeed. If the drain operation fails, the machine controller cannot proceed removing the machine.

    You can skip draining the node by annotating machine.openshift.io/exclude-node-draining in a specific machine.

Verification

  • Verify the deletion of the intended machine by running the following command: 

    $ oc get machines

Chapter 8. Windows node upgrades

You can ensure your Windows nodes have the latest updates by upgrading the Windows Machine Config Operator (WMCO).

8.1. Windows Machine Config Operator upgrades

When a new version of the Windows Machine Config Operator (WMCO) is released that is compatible with the current cluster version, the Operator is upgraded based on the upgrade channel and subscription approval strategy it was installed with when using the Operator Lifecycle Manager (OLM). The WMCO upgrade results in the Kubernetes components in the Windows machine being upgraded.

Note

If you are upgrading to a new version of the WMCO and want to use cluster monitoring, you must have the openshift.io/cluster-monitoring=true label present in the WMCO namespace. If you add the label to a pre-existing WMCO namespace, and there are already Windows nodes configured, restart the WMCO pod to allow monitoring graphs to display.

For a non-disruptive upgrade, the WMCO terminates the Windows machines configured by the previous version of the WMCO and recreates them using the current version. This is done by deleting the Machine object, which results in the drain and deletion of the Windows node. To facilitate an upgrade, the WMCO adds a version annotation to all the configured nodes. During an upgrade, a mismatch in version annotation results in the deletion and recreation of a Windows machine. To have minimal service disruptions during an upgrade, the WMCO only updates one Windows machine at a time.

Important

The WMCO is only responsible for updating Kubernetes components, not for Windows operating system updates. You provide the Windows image when creating the VMs; therefore, you are responsible for providing an updated image. You can provide an updated Windows image by changing the image configuration in the MachineSet spec.

For more information on Operator upgrades using the Operator Lifecycle Manager (OLM), see Updating installed Operators.

Chapter 9. Using Bring-Your-Own-Host (BYOH) Windows instances as nodes

Bring-Your-Own-Host (BYOH) allows for users to repurpose Windows Server VMs and bring them to OpenShift Container Platform. BYOH Windows instances benefit users looking to mitigate major disruptions in the event that a Windows server goes offline.

9.1. Configuring a BYOH Windows instance

Creating a BYOH Windows instance requires creating a config map in the Windows Machine Config Operator (WMCO) namespace.

Prerequisites

Any Windows instances that are to be attached to the cluster as a node must fulfill the following requirements:

  • The instance must be on the same network as the Linux worker nodes in the cluster.
  • Port 22 must be open and running an SSH server.
  • The default shell for the SSH server must be the Windows Command shell, or cmd.exe.
  • Port 10250 must be open for log collection.
  • An administrator user is present with the private key used in the secret set as an authorized SSH key.
  • If you are creating a BYOH Windows instance for an installer-provisioned infrastructure (IPI) AWS cluster, you must add a tag to the AWS instance that matches the spec.template.spec.value.tag value in the compute machine set for your worker nodes. For example, kubernetes.io/cluster/<cluster_id>: owned or kubernetes.io/cluster/<cluster_id>: shared.
  • If you are creating a BYOH Windows instance on vSphere, communication with the internal API server must be enabled.

  • The hostname of the instance must follow the RFC 1123 DNS label requirements, which include the following standards:

    • Contains only lowercase alphanumeric characters or '-'.
    • Starts with an alphanumeric character.
    • Ends with an alphanumeric character.
Note

Windows instances deployed by the WMCO are configured with the containerd container runtime. Because the WMCO installs and manages the runtime, it is recommended that you not manually install containerd on nodes.

Procedure

  1. Create a ConfigMap named windows-instances in the WMCO namespace that describes the Windows instances to be added.

    Note

    Format each entry in the config map’s data section by using the address as the key while formatting the value as username=<username>.

    Example config map

    kind: ConfigMap
apiVersion: v1
metadata:
  name: windows-instances
  namespace: openshift-windows-machine-config-operator
data:
  10.1.42.1: |- 1
    username=Administrator 2
  instance.example.com: |-
    username=core

    1
    The address that the WMCO uses to reach the instance over SSH, either a DNS name or an IPv4 address. A DNS PTR record must exist for this address. It is recommended that you use a DNS name with your BYOH instance if your organization uses DHCP to assign IP addresses. If not, you need to update the windows-instances ConfigMap whenever the instance is assigned a new IP address.
    2
    The name of the administrator user created in the prerequisites.

9.2. Removing BYOH Windows instances

You can remove BYOH instances attached to the cluster by deleting the instance’s entry in the config map. Deleting an instance reverts that instance back to its state prior to adding to the cluster. Any logs and container runtime artifacts are not added to these instances.

For an instance to be cleanly removed, it must be accessible with the current private key provided to WMCO. For example, to remove the 10.1.42.1 instance from the previous example, the config map would be changed to the following: 

kind: ConfigMap
apiVersion: v1
metadata:
  name: windows-instances
  namespace: openshift-windows-machine-config-operator
data:
  instance.example.com: |-
    username=core

Deleting windows-instances is viewed as a request to deconstruct all Windows instances added as nodes.

Chapter 10. Removing Windows nodes

You can remove a Windows node by deleting its host Windows machine.

10.1. Deleting a specific machine

You can delete a specific machine.

Important

Do not delete a control plane machine unless your cluster uses a control plane machine set.

Prerequisites

  • Install an OpenShift Container Platform cluster.
  • Install the OpenShift CLI (oc).
  • Log in to oc as a user with cluster-admin permission.

Procedure

  1. View the machines that are in the cluster by running the following command: 

    $ oc get machine -n openshift-machine-api

    The command output contains a list of machines in the <clusterid>-<role>-<cloud_region> format.

  2. Identify the machine that you want to delete.

  3. Delete the machine by running the following command: 

    $ oc delete machine <machine> -n openshift-machine-api
    Important

    By default, the machine controller tries to drain the node that is backed by the machine until it succeeds. In some situations, such as with a misconfigured pod disruption budget, the drain operation might not be able to succeed. If the drain operation fails, the machine controller cannot proceed removing the machine.

    You can skip draining the node by annotating machine.openshift.io/exclude-node-draining in a specific machine.

    If the machine that you delete belongs to a machine set, a new machine is immediately created to satisfy the specified number of replicas.

Chapter 11. Disabling Windows container workloads

You can disable the capability to run Windows container workloads by uninstalling the Windows Machine Config Operator (WMCO) and deleting the namespace that was added by default when you installed the WMCO.

11.1. Uninstalling the Windows Machine Config Operator

You can uninstall the Windows Machine Config Operator (WMCO) from your cluster.

Prerequisites

  • Delete the Windows Machine objects hosting your Windows workloads.

Procedure

  1. From the Operators → OperatorHub page, use the Filter by keyword box to search for Red Hat Windows Machine Config Operator.
  2. Click the Red Hat Windows Machine Config Operator tile. The Operator tile indicates it is installed.
  3. In the Windows Machine Config Operator descriptor page, click Uninstall.

11.2. Deleting the Windows Machine Config Operator namespace

You can delete the namespace that was generated for the Windows Machine Config Operator (WMCO) by default.

Prerequisites

  • The WMCO is removed from your cluster.

Procedure

  1. Remove all Windows workloads that were created in the openshift-windows-machine-config-operator namespace: 

    $ oc delete --all pods --namespace=openshift-windows-machine-config-operator

  2. Verify that all pods in the openshift-windows-machine-config-operator namespace are deleted or are reporting a terminating state: 

    $ oc get pods --namespace openshift-windows-machine-config-operator

  3. Delete the openshift-windows-machine-config-operator namespace: 

    $ oc delete namespace openshift-windows-machine-config-operator

Additional resources

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