Chapter 6. Postinstallation cluster tasks
After installing OpenShift Container Platform, you can further expand and customize your cluster to your requirements.
6.1. Available cluster customizations
You complete most of the cluster configuration and customization after you deploy your OpenShift Container Platform cluster. A number of configuration resources are available.
If you install your cluster on IBM Z, not all features and functions are available.
You modify the configuration resources to configure the major features of the cluster, such as the image registry, networking configuration, image build behavior, and the identity provider.
For current documentation of the settings that you control by using these resources, use the oc explain
command, for example oc explain builds --api-version=config.openshift.io/v1
6.1.1. Cluster configuration resources
All cluster configuration resources are globally scoped (not namespaced) and named cluster
.
Resource name | Description |
---|---|
| Provides API server configuration such as certificates and certificate authorities. |
| Controls the identity provider and authentication configuration for the cluster. |
| Controls default and enforced configuration for all builds on the cluster. |
| Configures the behavior of the web console interface, including the logout behavior. |
| Enables FeatureGates so that you can use Tech Preview features. |
| Configures how specific image registries should be treated (allowed, disallowed, insecure, CA details). |
| Configuration details related to routing such as the default domain for routes. |
| Configures identity providers and other behavior related to internal OAuth server flows. |
| Configures how projects are created including the project template. |
| Defines proxies to be used by components needing external network access. Note: not all components currently consume this value. |
| Configures scheduler behavior such as profiles and default node selectors. |
6.1.2. Operator configuration resources
These configuration resources are cluster-scoped instances, named cluster
, which control the behavior of a specific component as owned by a particular Operator.
Resource name | Description |
---|---|
| Controls console appearance such as branding customizations |
| Configures OpenShift image registry settings such as public routing, log levels, proxy settings, resource constraints, replica counts, and storage type. |
| Configures the Samples Operator to control which example image streams and templates are installed on the cluster. |
6.1.3. Additional configuration resources
These configuration resources represent a single instance of a particular component. In some cases, you can request multiple instances by creating multiple instances of the resource. In other cases, the Operator can use only a specific resource instance name in a specific namespace. Reference the component-specific documentation for details on how and when you can create additional resource instances.
Resource name | Instance name | Namespace | Description |
---|---|---|---|
|
|
| Controls the Alertmanager deployment parameters. |
|
|
| Configures Ingress Operator behavior such as domain, number of replicas, certificates, and controller placement. |
6.1.4. Informational Resources
You use these resources to retrieve information about the cluster. Some configurations might require you to edit these resources directly.
Resource name | Instance name | Description |
---|---|---|
|
|
In OpenShift Container Platform 4.13, you must not customize the |
|
| You cannot modify the DNS settings for your cluster. You can view the DNS Operator status. |
|
| Configuration details allowing the cluster to interact with its cloud provider. |
|
| You cannot modify your cluster networking after installation. To customize your network, follow the process to customize networking during installation. |
6.2. Adding worker nodes
After you deploy your OpenShift Container Platform cluster, you can add worker nodes to scale cluster resources. There are different ways you can add worker nodes depending on the installation method and the environment of your cluster.
6.2.1. Adding worker nodes to installer-provisioned infrastructure clusters
For installer-provisioned infrastructure clusters, you can manually or automatically scale the MachineSet
object to match the number of available bare-metal hosts.
To add a bare-metal host, you must configure all network prerequisites, configure an associated baremetalhost
object, then provision the worker node to the cluster. You can add a bare-metal host manually or by using the web console.
6.2.2. Adding worker nodes to user-provisioned infrastructure clusters
For user-provisioned infrastructure clusters, you can add worker nodes by using a RHEL or RHCOS ISO image and connecting it to your cluster using cluster Ignition config files. For RHEL worker nodes, the following example uses Ansible playbooks to add worker nodes to the cluster. For RHCOS worker nodes, the following example uses an ISO image and network booting to add worker nodes to the cluster.
6.2.3. Adding worker nodes to clusters managed by the Assisted Installer
For clusters managed by the Assisted Installer, you can add worker nodes by using the Red Hat OpenShift Cluster Manager console, the Assisted Installer REST API or you can manually add worker nodes using an ISO image and cluster Ignition config files.
6.2.4. Adding worker nodes to clusters managed by the multicluster engine for Kubernetes
For clusters managed by the multicluster engine for Kubernetes, you can add worker nodes by using the dedicated multicluster engine console.
6.3. Adjust worker nodes
If you incorrectly sized the worker nodes during deployment, adjust them by creating one or more new compute machine sets, scale them up, then scale the original compute machine set down before removing them.
6.3.1. Understanding the difference between compute machine sets and the machine config pool
MachineSet
objects describe OpenShift Container Platform nodes with respect to the cloud or machine provider.
The MachineConfigPool
object allows MachineConfigController
components to define and provide the status of machines in the context of upgrades.
The MachineConfigPool
object allows users to configure how upgrades are rolled out to the OpenShift Container Platform nodes in the machine config pool.
The NodeSelector
object can be replaced with a reference to the MachineSet
object.
6.3.2. 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 withcluster-admin
permission.
Procedure
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>
.View the compute machines that are in the cluster by running the following command:
$ oc get machine -n openshift-machine-api
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"
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
TipYou 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.
ImportantBy 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
6.3.3. The compute machine set deletion policy
Random
, Newest
, and Oldest
are the three supported deletion options. The default is Random
, meaning that random machines are chosen and deleted when scaling compute machine sets down. The deletion policy can be set according to the use case by modifying the particular compute machine set:
spec: deletePolicy: <delete_policy> replicas: <desired_replica_count>
Specific machines can also be prioritized for deletion by adding the annotation machine.openshift.io/delete-machine=true
to the machine of interest, regardless of the deletion policy.
By default, the OpenShift Container Platform router pods are deployed on workers. Because the router is required to access some cluster resources, including the web console, do not scale the worker compute machine set to 0
unless you first relocate the router pods.
Custom compute machine sets can be used for use cases requiring that services run on specific nodes and that those services are ignored by the controller when the worker compute machine sets are scaling down. This prevents service disruption.
6.3.4. Creating default cluster-wide node selectors
You can use default cluster-wide node selectors on pods together with labels on nodes to constrain all pods created in a cluster to specific nodes.
With cluster-wide node selectors, when you create a pod in that cluster, OpenShift Container Platform adds the default node selectors to the pod and schedules the pod on nodes with matching labels.
You configure cluster-wide node selectors by editing the Scheduler Operator custom resource (CR). You add labels to a node, a compute machine set, or a machine config. Adding the label to the compute machine set ensures that if the node or machine goes down, new nodes have the label. Labels added to a node or machine config do not persist if the node or machine goes down.
You can add additional key/value pairs to a pod. But you cannot add a different value for a default key.
Procedure
To add a default cluster-wide node selector:
Edit the Scheduler Operator CR to add the default cluster-wide node selectors:
$ oc edit scheduler cluster
Example Scheduler Operator CR with a node selector
apiVersion: config.openshift.io/v1 kind: Scheduler metadata: name: cluster ... spec: defaultNodeSelector: type=user-node,region=east 1 mastersSchedulable: false
- 1
- Add a node selector with the appropriate
<key>:<value>
pairs.
After making this change, wait for the pods in the
openshift-kube-apiserver
project to redeploy. This can take several minutes. The default cluster-wide node selector does not take effect until the pods redeploy.Add labels to a node by using a compute machine set or editing the node directly:
Use a compute machine set to add labels to nodes managed by the compute machine set when a node is created:
Run the following command to add labels to a
MachineSet
object:$ oc patch MachineSet <name> --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"<key>"="<value>","<key>"="<value>"}}]' -n openshift-machine-api 1
- 1
- Add a
<key>/<value>
pair for each label.
For example:
$ oc patch MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c --type='json' -p='[{"op":"add","path":"/spec/template/spec/metadata/labels", "value":{"type":"user-node","region":"east"}}]' -n openshift-machine-api
TipYou can alternatively apply the following YAML to add labels to a compute machine set:
apiVersion: machine.openshift.io/v1beta1 kind: MachineSet metadata: name: <machineset> namespace: openshift-machine-api spec: template: spec: metadata: labels: region: "east" type: "user-node"
Verify that the labels are added to the
MachineSet
object by using theoc edit
command:For example:
$ oc edit MachineSet abc612-msrtw-worker-us-east-1c -n openshift-machine-api
Example
MachineSet
objectapiVersion: machine.openshift.io/v1beta1 kind: MachineSet ... spec: ... template: metadata: ... spec: metadata: labels: region: east type: user-node ...
Redeploy the nodes associated with that compute machine set by scaling down to
0
and scaling up the nodes:For example:
$ oc scale --replicas=0 MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api
$ oc scale --replicas=1 MachineSet ci-ln-l8nry52-f76d1-hl7m7-worker-c -n openshift-machine-api
When the nodes are ready and available, verify that the label is added to the nodes by using the
oc get
command:$ oc get nodes -l <key>=<value>
For example:
$ oc get nodes -l type=user-node
Example output
NAME STATUS ROLES AGE VERSION ci-ln-l8nry52-f76d1-hl7m7-worker-c-vmqzp Ready worker 61s v1.26.0
Add labels directly to a node:
Edit the
Node
object for the node:$ oc label nodes <name> <key>=<value>
For example, to label a node:
$ oc label nodes ci-ln-l8nry52-f76d1-hl7m7-worker-b-tgq49 type=user-node region=east
TipYou can alternatively apply the following YAML to add labels to a node:
kind: Node apiVersion: v1 metadata: name: <node_name> labels: type: "user-node" region: "east"
Verify that the labels are added to the node using the
oc get
command:$ oc get nodes -l <key>=<value>,<key>=<value>
For example:
$ oc get nodes -l type=user-node,region=east
Example output
NAME STATUS ROLES AGE VERSION ci-ln-l8nry52-f76d1-hl7m7-worker-b-tgq49 Ready worker 17m v1.26.0
6.3.5. Creating user workloads in AWS Local Zones
After you create an Amazon Web Service (AWS) Local Zone environment, and you deploy your cluster, you can use edge worker nodes to create user workloads in Local Zone subnets.
After the openshift-installer
creates the cluster, the installation program automatically specifies a taint effect of NoSchedule
to each edge worker node. This means that a scheduler does not add a new pod, or deployment, to a node if the pod does not match the specified tolerations for a taint. You can modify the taint for better control over how each node creates a workload in each Local Zone subnet.
The openshift-installer
creates the compute machine set manifests file with node-role.kubernetes.io/edge
and node-role.kubernetes.io/worker
labels applied to each edge worker node that is located in a Local Zone subnet.
Prerequisites
-
You have access to the OpenShift CLI (
oc
). - You deployed your cluster in a Virtual Private Cloud (VPC) with defined Local Zone subnets.
-
You ensured that the compute machine set for the edge workers on Local Zone subnets specifies the taints for
node-role.kubernetes.io/edge
.
Procedure
Create a
deployment
resource YAML file for an example application to be deployed in the edge worker node that operates in a Local Zone subnet. Ensure that you specify the correct tolerations that match the taints for the edge worker node.Example of a configured
deployment
resource for an edge worker node that operates in a Local Zone subnetkind: Namespace apiVersion: v1 metadata: name: <local_zone_application_namespace> --- kind: PersistentVolumeClaim apiVersion: v1 metadata: name: <pvc_name> namespace: <local_zone_application_namespace> spec: accessModes: - ReadWriteOnce resources: requests: storage: 10Gi storageClassName: gp2-csi 1 volumeMode: Filesystem --- apiVersion: apps/v1 kind: Deployment 2 metadata: name: <local_zone_application> 3 namespace: <local_zone_application_namespace> 4 spec: selector: matchLabels: app: <local_zone_application> replicas: 1 template: metadata: labels: app: <local_zone_application> zone-group: ${ZONE_GROUP_NAME} 5 spec: securityContext: seccompProfile: type: RuntimeDefault nodeSelector: 6 machine.openshift.io/zone-group: ${ZONE_GROUP_NAME} tolerations: 7 - key: "node-role.kubernetes.io/edge" operator: "Equal" value: "" effect: "NoSchedule" containers: - image: openshift/origin-node command: - "/bin/socat" args: - TCP4-LISTEN:8080,reuseaddr,fork - EXEC:'/bin/bash -c \"printf \\\"HTTP/1.0 200 OK\r\n\r\n\\\"; sed -e \\\"/^\r/q\\\"\"' imagePullPolicy: Always name: echoserver ports: - containerPort: 8080 volumeMounts: - mountPath: "/mnt/storage" name: data volumes: - name: data persistentVolumeClaim: claimName: <pvc_name>
- 1
storageClassName
: For the Local Zone configuration, you must specifygp2-csi
.- 2
kind
: Defines thedeployment
resource.- 3
name
: Specifies the name of your Local Zone application. For example,local-zone-demo-app-nyc-1
.- 4
namespace:
Defines the namespace for the AWS Local Zone where you want to run the user workload. For example:local-zone-app-nyc-1a
.- 5
zone-group
: Defines the group to where a zone belongs. For example,us-east-1-iah-1
.- 6
nodeSelector
: Targets edge worker nodes that match the specified labels.- 7
tolerations
: Sets the values that match with thetaints
defined on theMachineSet
manifest for the Local Zone node.
Create a
service
resource YAML file for the node. This resource exposes a pod from a targeted edge worker node to services that run inside your Local Zone network.Example of a configured
service
resource for an edge worker node that operates in a Local Zone subnetapiVersion: v1 kind: Service 1 metadata: name: <local_zone_application> namespace: <local_zone_application_namespace> spec: ports: - port: 80 targetPort: 8080 protocol: TCP type: NodePort selector: 2 app: <local_zone_application>
Next steps
- Optional: Use the AWS Load Balancer (ALB) Operator to expose a pod from a targeted edge worker node to services that run inside a Local Zone subnet from a public network. See Installing the AWS Load Balancer Operator.
6.4. Improving cluster stability in high latency environments using worker latency profiles
If the cluster administrator has performed latency tests for platform verification, they can discover the need to adjust the operation of the cluster to ensure stability in cases of high latency. The cluster administrator need change only one parameter, recorded in a file, which controls four parameters affecting how supervisory processes read status and interpret the health of the cluster. Changing only the one parameter provides cluster tuning in an easy, supportable manner.
The Kubelet
process provides the starting point for monitoring cluster health. The Kubelet
sets status values for all nodes in the OpenShift Container Platform cluster. The Kubernetes Controller Manager (kube controller
) reads the status values every 10 seconds, by default. If the kube controller
cannot read a node status value, it loses contact with that node after a configured period. The default behavior is:
-
The node controller on the control plane updates the node health to
Unhealthy
and marks the nodeReady
condition`Unknown`. - In response, the scheduler stops scheduling pods to that node.
-
The Node Lifecycle Controller adds a
node.kubernetes.io/unreachable
taint with aNoExecute
effect to the node and schedules any pods on the node for eviction after five minutes, by default.
This behavior can cause problems if your network is prone to latency issues, especially if you have nodes at the network edge. In some cases, the Kubernetes Controller Manager might not receive an update from a healthy node due to network latency. The Kubelet
evicts pods from the node even though the node is healthy.
To avoid this problem, you can use worker latency profiles to adjust the frequency that the Kubelet
and the Kubernetes Controller Manager wait for status updates before taking action. These adjustments help to ensure that your cluster runs properly if network latency between the control plane and the worker nodes is not optimal.
These worker latency profiles contain three sets of parameters that are pre-defined with carefully tuned values to control the reaction of the cluster to increased latency. No need to experimentally find the best values manually.
You can configure worker latency profiles when installing a cluster or at any time you notice increased latency in your cluster network.
6.4.1. Understanding worker latency profiles
Worker latency profiles are four different categories of carefully-tuned parameters. The four parameters which implement these values are node-status-update-frequency
, node-monitor-grace-period
, default-not-ready-toleration-seconds
and default-unreachable-toleration-seconds
. These parameters can use values which allow you control the reaction of the cluster to latency issues without needing to determine the best values using manual methods.
Setting these parameters manually is not supported. Incorrect parameter settings adversely affect cluster stability.
All worker latency profiles configure the following parameters:
- node-status-update-frequency
- Specifies how often the kubelet posts node status to the API server.
- node-monitor-grace-period
-
Specifies the amount of time in seconds that the Kubernetes Controller Manager waits for an update from a kubelet before marking the node unhealthy and adding the
node.kubernetes.io/not-ready
ornode.kubernetes.io/unreachable
taint to the node. - default-not-ready-toleration-seconds
- Specifies the amount of time in seconds after marking a node unhealthy that the Kube API Server Operator waits before evicting pods from that node.
- default-unreachable-toleration-seconds
- Specifies the amount of time in seconds after marking a node unreachable that the Kube API Server Operator waits before evicting pods from that node.
The following Operators monitor the changes to the worker latency profiles and respond accordingly:
-
The Machine Config Operator (MCO) updates the
node-status-update-frequency
parameter on the worker nodes. -
The Kubernetes Controller Manager updates the
node-monitor-grace-period
parameter on the control plane nodes. -
The Kubernetes API Server Operator updates the
default-not-ready-toleration-seconds
anddefault-unreachable-toleration-seconds
parameters on the control plane nodes.
Although the default configuration works in most cases, OpenShift Container Platform offers two other worker latency profiles for situations where the network is experiencing higher latency than usual. The three worker latency profiles are described in the following sections:
- Default worker latency profile
With the
Default
profile, eachKubelet
updates it’s status every 10 seconds (node-status-update-frequency
). TheKube Controller Manager
checks the statuses ofKubelet
every 5 seconds (node-monitor-grace-period
).The Kubernetes Controller Manager waits 40 seconds for a status update from
Kubelet
before considering theKubelet
unhealthy. If no status is made available to the Kubernetes Controller Manager, it then marks the node with thenode.kubernetes.io/not-ready
ornode.kubernetes.io/unreachable
taint and evicts the pods on that node.If a pod on that node has the
NoExecute
taint, the pod is run according totolerationSeconds
. If the pod has no taint, it will be evicted in 300 seconds (default-not-ready-toleration-seconds
anddefault-unreachable-toleration-seconds
settings of theKube API Server
).Profile Component Parameter Value Default
kubelet
node-status-update-frequency
10s
Kubelet Controller Manager
node-monitor-grace-period
40s
Kubernetes API Server Operator
default-not-ready-toleration-seconds
300s
Kubernetes API Server Operator
default-unreachable-toleration-seconds
300s
- Medium worker latency profile
Use the
MediumUpdateAverageReaction
profile if the network latency is slightly higher than usual.The
MediumUpdateAverageReaction
profile reduces the frequency of kubelet updates to 20 seconds and changes the period that the Kubernetes Controller Manager waits for those updates to 2 minutes. The pod eviction period for a pod on that node is reduced to 60 seconds. If the pod has thetolerationSeconds
parameter, the eviction waits for the period specified by that parameter.The Kubernetes Controller Manager waits for 2 minutes to consider a node unhealthy. In another minute, the eviction process starts.
Profile Component Parameter Value MediumUpdateAverageReaction
kubelet
node-status-update-frequency
20s
Kubelet Controller Manager
node-monitor-grace-period
2m
Kubernetes API Server Operator
default-not-ready-toleration-seconds
60s
Kubernetes API Server Operator
default-unreachable-toleration-seconds
60s
- Low worker latency profile
Use the
LowUpdateSlowReaction
profile if the network latency is extremely high.The
LowUpdateSlowReaction
profile reduces the frequency of kubelet updates to 1 minute and changes the period that the Kubernetes Controller Manager waits for those updates to 5 minutes. The pod eviction period for a pod on that node is reduced to 60 seconds. If the pod has thetolerationSeconds
parameter, the eviction waits for the period specified by that parameter.The Kubernetes Controller Manager waits for 5 minutes to consider a node unhealthy. In another minute, the eviction process starts.
Profile Component Parameter Value LowUpdateSlowReaction
kubelet
node-status-update-frequency
1m
Kubelet Controller Manager
node-monitor-grace-period
5m
Kubernetes API Server Operator
default-not-ready-toleration-seconds
60s
Kubernetes API Server Operator
default-unreachable-toleration-seconds
60s
6.4.2. Using and changing worker latency profiles
To change a worker latency profile to deal with network latency, edit the node.config
object to add the name of the profile. You can change the profile at any time as latency increases or decreases.
You must move one worker latency profile at a time. For example, you cannot move directly from the Default
profile to the LowUpdateSlowReaction
worker latency profile. You must move from the Default
worker latency profile to the MediumUpdateAverageReaction
profile first, then to LowUpdateSlowReaction
. Similarly, when returning to the Default
profile, you must move from the low profile to the medium profile first, then to Default
.
You can also configure worker latency profiles upon installing an OpenShift Container Platform cluster.
Procedure
To move from the default worker latency profile:
Move to the medium worker latency profile:
Edit the
node.config
object:$ oc edit nodes.config/cluster
Add
spec.workerLatencyProfile: MediumUpdateAverageReaction
:Example
node.config
objectapiVersion: config.openshift.io/v1 kind: Node metadata: annotations: include.release.openshift.io/ibm-cloud-managed: "true" include.release.openshift.io/self-managed-high-availability: "true" include.release.openshift.io/single-node-developer: "true" release.openshift.io/create-only: "true" creationTimestamp: "2022-07-08T16:02:51Z" generation: 1 name: cluster ownerReferences: - apiVersion: config.openshift.io/v1 kind: ClusterVersion name: version uid: 36282574-bf9f-409e-a6cd-3032939293eb resourceVersion: "1865" uid: 0c0f7a4c-4307-4187-b591-6155695ac85b spec: workerLatencyProfile: MediumUpdateAverageReaction 1 # ...
- 1
- Specifies the medium worker latency policy.
Scheduling on each worker node is disabled as the change is being applied.
Optional: Move to the low worker latency profile:
Edit the
node.config
object:$ oc edit nodes.config/cluster
Change the
spec.workerLatencyProfile
value toLowUpdateSlowReaction
:Example
node.config
objectapiVersion: config.openshift.io/v1 kind: Node metadata: annotations: include.release.openshift.io/ibm-cloud-managed: "true" include.release.openshift.io/self-managed-high-availability: "true" include.release.openshift.io/single-node-developer: "true" release.openshift.io/create-only: "true" creationTimestamp: "2022-07-08T16:02:51Z" generation: 1 name: cluster ownerReferences: - apiVersion: config.openshift.io/v1 kind: ClusterVersion name: version uid: 36282574-bf9f-409e-a6cd-3032939293eb resourceVersion: "1865" uid: 0c0f7a4c-4307-4187-b591-6155695ac85b spec: workerLatencyProfile: LowUpdateSlowReaction 1 # ...
- 1
- Specifies use of the low worker latency policy.
Scheduling on each worker node is disabled as the change is being applied.
Verification
When all nodes return to the
Ready
condition, you can use the following command to look in the Kubernetes Controller Manager to ensure it was applied:$ oc get KubeControllerManager -o yaml | grep -i workerlatency -A 5 -B 5
Example output
# ... - lastTransitionTime: "2022-07-11T19:47:10Z" reason: ProfileUpdated status: "False" type: WorkerLatencyProfileProgressing - lastTransitionTime: "2022-07-11T19:47:10Z" 1 message: all static pod revision(s) have updated latency profile reason: ProfileUpdated status: "True" type: WorkerLatencyProfileComplete - lastTransitionTime: "2022-07-11T19:20:11Z" reason: AsExpected status: "False" type: WorkerLatencyProfileDegraded - lastTransitionTime: "2022-07-11T19:20:36Z" status: "False" # ...
- 1
- Specifies that the profile is applied and active.
To change the medium profile to default or change the default to medium, edit the node.config
object and set the spec.workerLatencyProfile
parameter to the appropriate value.
6.5. Managing control plane machines
Control plane machine sets provide management capabilities for control plane machines that are similar to what compute machine sets provide for compute machines. The availability and initial status of control plane machine sets on your cluster depend on your cloud provider and the version of OpenShift Container Platform that you installed. For more information, see Getting started with control plane machine sets.
6.6. Creating infrastructure machine sets for production environments
You can create a compute machine set to create machines that host only infrastructure components, such as the default router, the integrated container image registry, and components for cluster metrics and monitoring. These infrastructure machines are not counted toward the total number of subscriptions that are required to run the environment.
In a production deployment, it is recommended that you deploy at least three compute machine sets to hold infrastructure components. Both OpenShift Logging and Red Hat OpenShift Service Mesh deploy Elasticsearch, which requires three instances to be installed on different nodes. Each of these nodes can be deployed to different availability zones for high availability. A configuration like this requires three different compute machine sets, one for each availability zone. In global Azure regions that do not have multiple availability zones, you can use availability sets to ensure high availability.
For information on infrastructure nodes and which components can run on infrastructure nodes, see Creating infrastructure machine sets.
To create an infrastructure node, you can use a machine set, assign a label to the nodes, or use a machine config pool.
For sample machine sets that you can use with these procedures, see Creating machine sets for different clouds.
Applying a specific node selector to all infrastructure components causes OpenShift Container Platform to schedule those workloads on nodes with that label.
6.6.1. 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 withcluster-admin
permission.
Procedure
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.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.
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
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
andinfra
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.
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
andCURRENT
values match. If the compute machine set is not available, wait a few minutes and run the command again.
6.6.2. Creating an infrastructure node
See Creating infrastructure machine sets for installer-provisioned infrastructure environments or for any cluster where the control plane nodes are managed by the machine API.
Requirements of the cluster dictate that infrastructure, also called infra
nodes, be provisioned. The installer only provides provisions for control plane and worker nodes. Worker nodes can be designated as infrastructure nodes or application, also called app
, nodes through labeling.
Procedure
Add a label to the worker node that you want to act as application node:
$ oc label node <node-name> node-role.kubernetes.io/app=""
Add a label to the worker nodes that you want to act as infrastructure nodes:
$ oc label node <node-name> node-role.kubernetes.io/infra=""
Check to see if applicable nodes now have the
infra
role andapp
roles:$ oc get nodes
Create a default cluster-wide node selector. The default node selector is applied to pods created in all namespaces. This creates an intersection with any existing node selectors on a pod, which additionally constrains the pod’s selector.
ImportantIf the default node selector key conflicts with the key of a pod’s label, then the default node selector is not applied.
However, do not set a default node selector that might cause a pod to become unschedulable. For example, setting the default node selector to a specific node role, such as
node-role.kubernetes.io/infra=""
, when a pod’s label is set to a different node role, such asnode-role.kubernetes.io/master=""
, can cause the pod to become unschedulable. For this reason, use caution when setting the default node selector to specific node roles.You can alternatively use a project node selector to avoid cluster-wide node selector key conflicts.
Edit the
Scheduler
object:$ oc edit scheduler cluster
Add the
defaultNodeSelector
field with the appropriate node selector:apiVersion: config.openshift.io/v1 kind: Scheduler metadata: name: cluster spec: defaultNodeSelector: node-role.kubernetes.io/infra="" 1 # ...
- 1
- This example node selector deploys pods on infrastructure nodes by default.
- Save the file to apply the changes.
You can now move infrastructure resources to the newly labeled infra
nodes.
Additional resources
- For information on how to configure project node selectors to avoid cluster-wide node selector key conflicts, see Project node selectors.
6.6.3. Creating a machine config pool for infrastructure machines
If you need infrastructure machines to have dedicated configurations, you must create an infra pool.
Procedure
Add a label to the node you want to assign as the infra node with a specific label:
$ oc label node <node_name> <label>
$ oc label node ci-ln-n8mqwr2-f76d1-xscn2-worker-c-6fmtx node-role.kubernetes.io/infra=
Create a machine config pool that contains both the worker role and your custom role as machine config selector:
$ cat infra.mcp.yaml
Example output
apiVersion: machineconfiguration.openshift.io/v1 kind: MachineConfigPool metadata: name: infra spec: machineConfigSelector: matchExpressions: - {key: machineconfiguration.openshift.io/role, operator: In, values: [worker,infra]} 1 nodeSelector: matchLabels: node-role.kubernetes.io/infra: "" 2
NoteCustom machine config pools inherit machine configs from the worker pool. Custom pools use any machine config targeted for the worker pool, but add the ability to also deploy changes that are targeted at only the custom pool. Because a custom pool inherits resources from the worker pool, any change to the worker pool also affects the custom pool.
After you have the YAML file, you can create the machine config pool:
$ oc create -f infra.mcp.yaml
Check the machine configs to ensure that the infrastructure configuration rendered successfully:
$ oc get machineconfig
Example output
NAME GENERATEDBYCONTROLLER IGNITIONVERSION CREATED 00-master 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 00-worker 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 01-master-container-runtime 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 01-master-kubelet 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 01-worker-container-runtime 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 01-worker-kubelet 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 99-master-1ae2a1e0-a115-11e9-8f14-005056899d54-registries 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 99-master-ssh 3.2.0 31d 99-worker-1ae64748-a115-11e9-8f14-005056899d54-registries 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 31d 99-worker-ssh 3.2.0 31d rendered-infra-4e48906dca84ee702959c71a53ee80e7 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 23m rendered-master-072d4b2da7f88162636902b074e9e28e 5b6fb8349a29735e48446d435962dec4547d3090 3.2.0 31d rendered-master-3e88ec72aed3886dec061df60d16d1af 02c07496ba0417b3e12b78fb32baf6293d314f79 3.2.0 31d rendered-master-419bee7de96134963a15fdf9dd473b25 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 17d rendered-master-53f5c91c7661708adce18739cc0f40fb 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 13d rendered-master-a6a357ec18e5bce7f5ac426fc7c5ffcd 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 7d3h rendered-master-dc7f874ec77fc4b969674204332da037 5b6fb8349a29735e48446d435962dec4547d3090 3.2.0 31d rendered-worker-1a75960c52ad18ff5dfa6674eb7e533d 5b6fb8349a29735e48446d435962dec4547d3090 3.2.0 31d rendered-worker-2640531be11ba43c61d72e82dc634ce6 5b6fb8349a29735e48446d435962dec4547d3090 3.2.0 31d rendered-worker-4e48906dca84ee702959c71a53ee80e7 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 7d3h rendered-worker-4f110718fe88e5f349987854a1147755 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 17d rendered-worker-afc758e194d6188677eb837842d3b379 02c07496ba0417b3e12b78fb32baf6293d314f79 3.2.0 31d rendered-worker-daa08cc1e8f5fcdeba24de60cd955cc3 365c1cfd14de5b0e3b85e0fc815b0060f36ab955 3.2.0 13d
You should see a new machine config, with the
rendered-infra-*
prefix.Optional: To deploy changes to a custom pool, create a machine config that uses the custom pool name as the label, such as
infra
. Note that this is not required and only shown for instructional purposes. In this manner, you can apply any custom configurations specific to only your infra nodes.NoteAfter you create the new machine config pool, the MCO generates a new rendered config for that pool, and associated nodes of that pool reboot to apply the new configuration.
Create a machine config:
$ cat infra.mc.yaml
Example output
apiVersion: machineconfiguration.openshift.io/v1 kind: MachineConfig metadata: name: 51-infra labels: machineconfiguration.openshift.io/role: infra 1 spec: config: ignition: version: 3.2.0 storage: files: - path: /etc/infratest mode: 0644 contents: source: data:,infra
- 1
- Add the label you added to the node as a
nodeSelector
.
Apply the machine config to the infra-labeled nodes:
$ oc create -f infra.mc.yaml
Confirm that your new machine config pool is available:
$ oc get mcp
Example output
NAME CONFIG UPDATED UPDATING DEGRADED MACHINECOUNT READYMACHINECOUNT UPDATEDMACHINECOUNT DEGRADEDMACHINECOUNT AGE infra rendered-infra-60e35c2e99f42d976e084fa94da4d0fc True False False 1 1 1 0 4m20s master rendered-master-9360fdb895d4c131c7c4bebbae099c90 True False False 3 3 3 0 91m worker rendered-worker-60e35c2e99f42d976e084fa94da4d0fc True False False 2 2 2 0 91m
In this example, a worker node was changed to an infra node.
Additional resources
- See Node configuration management with machine config pools for more information on grouping infra machines in a custom pool.
6.7. Assigning machine set resources to infrastructure nodes
After creating an infrastructure machine set, the worker
and infra
roles are applied to new infra nodes. Nodes with the infra
role are not counted toward the total number of subscriptions that are required to run the environment, even when the worker
role is also applied.
However, when an infra node is assigned the worker role, there is a chance that user workloads can get assigned inadvertently to the infra node. To avoid this, you can apply a taint to the infra node and tolerations for the pods that you want to control.
6.7.1. Binding infrastructure node workloads using taints and tolerations
If you have an infra node that has the infra
and worker
roles assigned, you must configure the node so that user workloads are not assigned to it.
It is recommended that you preserve the dual infra,worker
label that is created for infra nodes and use taints and tolerations to manage nodes that user workloads are scheduled on. If you remove the worker
label from the node, you must create a custom pool to manage it. A node with a label other than master
or worker
is not recognized by the MCO without a custom pool. Maintaining the worker
label allows the node to be managed by the default worker machine config pool, if no custom pools that select the custom label exists. The infra
label communicates to the cluster that it does not count toward the total number of subscriptions.
Prerequisites
-
Configure additional
MachineSet
objects in your OpenShift Container Platform cluster.
Procedure
Add a taint to the infra node to prevent scheduling user workloads on it:
Determine if the node has the taint:
$ oc describe nodes <node_name>
Sample output
oc describe node ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l Name: ci-ln-iyhx092-f76d1-nvdfm-worker-b-wln2l Roles: worker ... Taints: node-role.kubernetes.io/infra:NoSchedule ...
This example shows that the node has a taint. You can proceed with adding a toleration to your pod in the next step.
If you have not configured a taint to prevent scheduling user workloads on it:
$ oc adm taint nodes <node_name> <key>=<value>:<effect>
For example:
$ oc adm taint nodes node1 node-role.kubernetes.io/infra=reserved:NoSchedule
TipYou can alternatively apply the following YAML to add the taint:
kind: Node apiVersion: v1 metadata: name: <node_name> labels: ... spec: taints: - key: node-role.kubernetes.io/infra effect: NoSchedule value: reserved ...
This example places a taint on
node1
that has keynode-role.kubernetes.io/infra
and taint effectNoSchedule
. Nodes with theNoSchedule
effect schedule only pods that tolerate the taint, but allow existing pods to remain scheduled on the node.NoteIf a descheduler is used, pods violating node taints could be evicted from the cluster.
Add the taint with NoExecute Effect along with the above taint with NoSchedule Effect:
$ oc adm taint nodes <node_name> <key>=<value>:<effect>
For example:
$ oc adm taint nodes node1 node-role.kubernetes.io/infra=reserved:NoExecute
TipYou can alternatively apply the following YAML to add the taint:
kind: Node apiVersion: v1 metadata: name: <node_name> labels: ... spec: taints: - key: node-role.kubernetes.io/infra effect: NoExecute value: reserved ...
This example places a taint on
node1
that has the keynode-role.kubernetes.io/infra
and taint effectNoExecute
. Nodes with theNoExecute
effect schedule only pods that tolerate the taint. The effect will remove any existing pods from the node that do not have a matching toleration.
Add tolerations for the pod configurations you want to schedule on the infra node, like router, registry, and monitoring workloads. Add the following code to the
Pod
object specification:tolerations: - effect: NoSchedule 1 key: node-role.kubernetes.io/infra 2 value: reserved 3 - effect: NoExecute 4 key: node-role.kubernetes.io/infra 5 operator: Exists 6 value: reserved 7
- 1
- Specify the effect that you added to the node.
- 2
- Specify the key that you added to the node.
- 3
- Specify the value of the key-value pair taint that you added to the node.
- 4
- Specify the effect that you added to the node.
- 5
- Specify the key that you added to the node.
- 6
- Specify the
Exists
Operator to require a taint with the keynode-role.kubernetes.io/infra
to be present on the node. - 7
- Specify the value of the key-value pair taint that you added to the node.
This toleration matches the taint created by the
oc adm taint
command. A pod with this toleration can be scheduled onto the infra node.NoteMoving pods for an Operator installed via OLM to an infra node is not always possible. The capability to move Operator pods depends on the configuration of each Operator.
- Schedule the pod to the infra node using a scheduler. See the documentation for Controlling pod placement onto nodes for details.
Additional resources
- See Controlling pod placement using the scheduler for general information on scheduling a pod to a node.
6.8. Moving resources to infrastructure machine sets
Some of the infrastructure resources are deployed in your cluster by default. You can move them to the infrastructure machine sets that you created.
6.8.1. Moving the router
You can deploy the router pod to a different compute machine set. By default, the pod is deployed to a worker node.
Prerequisites
- Configure additional compute machine sets in your OpenShift Container Platform cluster.
Procedure
View the
IngressController
custom resource for the router Operator:$ oc get ingresscontroller default -n openshift-ingress-operator -o yaml
The command output resembles the following text:
apiVersion: operator.openshift.io/v1 kind: IngressController metadata: creationTimestamp: 2019-04-18T12:35:39Z finalizers: - ingresscontroller.operator.openshift.io/finalizer-ingresscontroller generation: 1 name: default namespace: openshift-ingress-operator resourceVersion: "11341" selfLink: /apis/operator.openshift.io/v1/namespaces/openshift-ingress-operator/ingresscontrollers/default uid: 79509e05-61d6-11e9-bc55-02ce4781844a spec: {} status: availableReplicas: 2 conditions: - lastTransitionTime: 2019-04-18T12:36:15Z status: "True" type: Available domain: apps.<cluster>.example.com endpointPublishingStrategy: type: LoadBalancerService selector: ingresscontroller.operator.openshift.io/deployment-ingresscontroller=default
Edit the
ingresscontroller
resource and change thenodeSelector
to use theinfra
label:$ oc edit ingresscontroller default -n openshift-ingress-operator
spec: nodePlacement: nodeSelector: 1 matchLabels: node-role.kubernetes.io/infra: "" tolerations: - effect: NoSchedule key: node-role.kubernetes.io/infra value: reserved - effect: NoExecute key: node-role.kubernetes.io/infra value: reserved
- 1
- Add a
nodeSelector
parameter with the appropriate value to the component you want to move. You can use anodeSelector
in the format shown or use<key>: <value>
pairs, based on the value specified for the node. If you added a taint to the infrastructure node, also add a matching toleration.
Confirm that the router pod is running on the
infra
node.View the list of router pods and note the node name of the running pod:
$ oc get pod -n openshift-ingress -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES router-default-86798b4b5d-bdlvd 1/1 Running 0 28s 10.130.2.4 ip-10-0-217-226.ec2.internal <none> <none> router-default-955d875f4-255g8 0/1 Terminating 0 19h 10.129.2.4 ip-10-0-148-172.ec2.internal <none> <none>
In this example, the running pod is on the
ip-10-0-217-226.ec2.internal
node.View the node status of the running pod:
$ oc get node <node_name> 1
- 1
- Specify the
<node_name>
that you obtained from the pod list.
Example output
NAME STATUS ROLES AGE VERSION ip-10-0-217-226.ec2.internal Ready infra,worker 17h v1.26.0
Because the role list includes
infra
, the pod is running on the correct node.
6.8.2. Moving the default registry
You configure the registry Operator to deploy its pods to different nodes.
Prerequisites
- Configure additional compute machine sets in your OpenShift Container Platform cluster.
Procedure
View the
config/instance
object:$ oc get configs.imageregistry.operator.openshift.io/cluster -o yaml
Example output
apiVersion: imageregistry.operator.openshift.io/v1 kind: Config metadata: creationTimestamp: 2019-02-05T13:52:05Z finalizers: - imageregistry.operator.openshift.io/finalizer generation: 1 name: cluster resourceVersion: "56174" selfLink: /apis/imageregistry.operator.openshift.io/v1/configs/cluster uid: 36fd3724-294d-11e9-a524-12ffeee2931b spec: httpSecret: d9a012ccd117b1e6616ceccb2c3bb66a5fed1b5e481623 logging: 2 managementState: Managed proxy: {} replicas: 1 requests: read: {} write: {} storage: s3: bucket: image-registry-us-east-1-c92e88cad85b48ec8b312344dff03c82-392c region: us-east-1 status: ...
Edit the
config/instance
object:$ oc edit configs.imageregistry.operator.openshift.io/cluster
spec: affinity: podAntiAffinity: preferredDuringSchedulingIgnoredDuringExecution: - podAffinityTerm: namespaces: - openshift-image-registry topologyKey: kubernetes.io/hostname weight: 100 logLevel: Normal managementState: Managed nodeSelector: 1 node-role.kubernetes.io/infra: "" tolerations: - effect: NoSchedule key: node-role.kubernetes.io/infra value: reserved - effect: NoExecute key: node-role.kubernetes.io/infra value: reserved
- 1
- Add a
nodeSelector
parameter with the appropriate value to the component you want to move. You can use anodeSelector
in the format shown or use<key>: <value>
pairs, based on the value specified for the node. If you added a taint to the infrasructure node, also add a matching toleration.
Verify the registry pod has been moved to the infrastructure node.
Run the following command to identify the node where the registry pod is located:
$ oc get pods -o wide -n openshift-image-registry
Confirm the node has the label you specified:
$ oc describe node <node_name>
Review the command output and confirm that
node-role.kubernetes.io/infra
is in theLABELS
list.
6.8.3. Moving the monitoring solution
The monitoring stack includes multiple components, including Prometheus, Thanos Querier, and Alertmanager. The Cluster Monitoring Operator manages this stack. To redeploy the monitoring stack to infrastructure nodes, you can create and apply a custom config map.
Procedure
Edit the
cluster-monitoring-config
config map and change thenodeSelector
to use theinfra
label:$ oc edit configmap cluster-monitoring-config -n openshift-monitoring
apiVersion: v1 kind: ConfigMap metadata: name: cluster-monitoring-config namespace: openshift-monitoring data: config.yaml: |+ alertmanagerMain: nodeSelector: 1 node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute prometheusK8s: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute prometheusOperator: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute k8sPrometheusAdapter: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute kubeStateMetrics: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute telemeterClient: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute openshiftStateMetrics: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute thanosQuerier: nodeSelector: node-role.kubernetes.io/infra: "" tolerations: - key: node-role.kubernetes.io/infra value: reserved effect: NoSchedule - key: node-role.kubernetes.io/infra value: reserved effect: NoExecute
- 1
- Add a
nodeSelector
parameter with the appropriate value to the component you want to move. You can use anodeSelector
in the format shown or use<key>: <value>
pairs, based on the value specified for the node. If you added a taint to the infrasructure node, also add a matching toleration.
Watch the monitoring pods move to the new machines:
$ watch 'oc get pod -n openshift-monitoring -o wide'
If a component has not moved to the
infra
node, delete the pod with this component:$ oc delete pod -n openshift-monitoring <pod>
The component from the deleted pod is re-created on the
infra
node.
6.8.4. Moving logging resources
For information about moving logging resources, see:
6.9. Applying autoscaling to your cluster
Applying autoscaling to an OpenShift Container Platform cluster involves deploying a cluster autoscaler and then deploying machine autoscalers for each machine type in your cluster.
For more information, see Applying autoscaling to an OpenShift Container Platform cluster.
6.10. Configuring Linux cgroup
Linux control group version 1 (cgroup v1) is enabled by default. You can enable Linux control group version 2 (cgroup v2) in your cluster by editing the node.config
object. Enabling cgroup v2 in OpenShift Container Platform disables all cgroup version 1 controllers and hierarchies in your cluster.
cgroup v2 is the current version of the Linux cgroup API. cgroup v2 offers several improvements over cgroup v1, including a unified hierarchy, safer sub-tree delegation, new features such as Pressure Stall Information, and enhanced resource management and isolation. However, cgroup v2 has different CPU, memory, and I/O management characteristics than cgroup v1. Therefore, some workloads might experience slight differences in memory or CPU usage on clusters that run cgroup v2.
You can change between cgroup v1 and cgroup v2, as needed. For more information, see "Configuring the Linux cgroup on your nodes" in the "Additional resources" of this section.
Currently, disabling CPU load balancing is not supported by cgroup v2. As a result, you might not get the desired behavior from performance profiles if you have cgroup v2 enabled. Enabling cgroup v2 is not recommended if you are using performance profiles.
Prerequisites
- You have a running OpenShift Container Platform cluster that uses version 4.12 or later.
- You are logged in to the cluster as a user with administrative privileges.
Procedure
Enable cgroup v2 on nodes:
Edit the
node.config
object:$ oc edit nodes.config/cluster
Add
spec.cgroupMode: "v2"
:Example
node.config
objectapiVersion: config.openshift.io/v1 kind: Node metadata: annotations: include.release.openshift.io/ibm-cloud-managed: "true" include.release.openshift.io/self-managed-high-availability: "true" include.release.openshift.io/single-node-developer: "true" release.openshift.io/create-only: "true" creationTimestamp: "2022-07-08T16:02:51Z" generation: 1 name: cluster ownerReferences: - apiVersion: config.openshift.io/v1 kind: ClusterVersion name: version uid: 36282574-bf9f-409e-a6cd-3032939293eb resourceVersion: "1865" uid: 0c0f7a4c-4307-4187-b591-6155695ac85b spec: cgroupMode: "v2" 1 ...
- 1
- Enables cgroup v2.
Verification
Check the machine configs to see that the new machine configs were added:
$ oc get mc
Example output
NAME GENERATEDBYCONTROLLER IGNITIONVERSION AGE 00-master 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 00-worker 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 01-master-container-runtime 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 01-master-kubelet 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 01-worker-container-runtime 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 01-worker-kubelet 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 97-master-generated-kubelet 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 99-worker-generated-kubelet 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 99-master-generated-registries 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 99-master-ssh 3.2.0 40m 99-worker-generated-registries 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m 99-worker-ssh 3.2.0 40m rendered-master-23d4317815a5f854bd3553d689cfe2e9 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 10s 1 rendered-master-23e785de7587df95a4b517e0647e5ab7 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m rendered-worker-5d596d9293ca3ea80c896a1191735bb1 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 33m rendered-worker-dcc7f1b92892d34db74d6832bcc9ccd4 52dd3ba6a9a527fc3ab42afac8d12b693534c8c9 3.2.0 10s
- 1
- New machine configs are created, as expected.
Check that the new
kernelArguments
were added to the new machine configs:$ oc describe mc <name>
Example output for cgroup v2
apiVersion: machineconfiguration.openshift.io/v1 kind: MachineConfig metadata: labels: machineconfiguration.openshift.io/role: worker name: 05-worker-kernelarg-selinuxpermissive spec: kernelArguments: - systemd_unified_cgroup_hierarchy=1 1 - cgroup_no_v1="all" 2 - psi=1 3
Check the nodes to see that scheduling on the nodes is disabled. This indicates that the change is being applied:
$ oc get nodes
Example output
NAME STATUS ROLES AGE VERSION ci-ln-fm1qnwt-72292-99kt6-master-0 Ready,SchedulingDisabled master 58m v1.26.0 ci-ln-fm1qnwt-72292-99kt6-master-1 Ready master 58m v1.26.0 ci-ln-fm1qnwt-72292-99kt6-master-2 Ready master 58m v1.26.0 ci-ln-fm1qnwt-72292-99kt6-worker-a-h5gt4 Ready,SchedulingDisabled worker 48m v1.26.0 ci-ln-fm1qnwt-72292-99kt6-worker-b-7vtmd Ready worker 48m v1.26.0 ci-ln-fm1qnwt-72292-99kt6-worker-c-rhzkv Ready worker 48m v1.26.0
After a node returns to the
Ready
state, start a debug session for that node:$ oc debug node/<node_name>
Set
/host
as the root directory within the debug shell:sh-4.4# chroot /host
Check that the
sys/fs/cgroup/cgroup2fs
file is present on your nodes. This file is created by cgroup v2:$ stat -c %T -f /sys/fs/cgroup
Example output
cgroup2fs
Additional resources
6.11. Enabling Technology Preview features using FeatureGates
You can turn on a subset of the current Technology Preview features on for all nodes in the cluster by editing the FeatureGate
custom resource (CR).
6.11.1. Understanding feature gates
You can use the FeatureGate
custom resource (CR) to enable specific feature sets in your cluster. A feature set is a collection of OpenShift Container Platform features that are not enabled by default.
You can activate the following feature set by using the FeatureGate
CR:
TechPreviewNoUpgrade
. This feature set is a subset of the current Technology Preview features. This feature set allows you to enable these Technology Preview features on test clusters, where you can fully test them, while leaving the features disabled on production clusters.WarningEnabling the
TechPreviewNoUpgrade
feature set on your cluster cannot be undone and prevents minor version updates. You should not enable this feature set on production clusters.The following Technology Preview features are enabled by this feature set:
-
External cloud providers. Enables support for external cloud providers for clusters on vSphere, AWS, Azure, and GCP. Support for OpenStack is GA. This is an internal feature that most users do not need to interact with. (
ExternalCloudProvider
) -
Shared Resources CSI Driver and Build CSI Volumes in OpenShift Builds. Enables the Container Storage Interface (CSI). (
CSIDriverSharedResource
) -
CSI volumes. Enables CSI volume support for the OpenShift Container Platform build system. (
BuildCSIVolumes
) -
Swap memory on nodes. Enables swap memory use for OpenShift Container Platform workloads on a per-node basis. (
NodeSwap
) -
OpenStack Machine API Provider. This gate has no effect and is planned to be removed from this feature set in a future release. (
MachineAPIProviderOpenStack
) -
Insights Operator. Enables the
InsightsDataGather
CRD, which allows users to configure some Insights data gathering options. -
Pod topology spread constraints. Enables the
matchLabelKeys
parameter for pod topology constraints. The parameter is list of pod label keys to select the pods over which spreading will be calculated. (MatchLabelKeysInPodTopologySpread
) -
Retroactive Default Storage Class. Enables OpenShift Container Platform to retroactively assign the default storage class to PVCs if there was no default storage class when the PVC was created.(
RetroactiveDefaultStorageClass
) -
Pod disruption budget (PDB) unhealthy pod eviction policy. Enables support for specifying how unhealthy pods are considered for eviction when using PDBs. (
PDBUnhealthyPodEvictionPolicy
) -
Dynamic Resource Allocation API. Enables a new API for requesting and sharing resources between pods and containers. This is an internal feature that most users do not need to interact with. (
DynamicResourceAllocation
) -
Pod security admission enforcement. Enables the restricted enforcement mode for pod security admission. Instead of only logging a warning, pods are rejected if they violate pod security standards. (
OpenShiftPodSecurityAdmission
)
-
External cloud providers. Enables support for external cloud providers for clusters on vSphere, AWS, Azure, and GCP. Support for OpenStack is GA. This is an internal feature that most users do not need to interact with. (
6.11.2. Enabling feature sets using the web console
You can use the OpenShift Container Platform web console to enable feature sets for all of the nodes in a cluster by editing the FeatureGate
custom resource (CR).
Procedure
To enable feature sets:
-
In the OpenShift Container Platform web console, switch to the Administration
Custom Resource Definitions page. - On the Custom Resource Definitions page, click FeatureGate.
- On the Custom Resource Definition Details page, click the Instances tab.
- Click the cluster feature gate, then click the YAML tab.
Edit the cluster instance to add specific feature sets:
WarningEnabling the
TechPreviewNoUpgrade
feature set on your cluster cannot be undone and prevents minor version updates. You should not enable this feature set on production clusters.Sample Feature Gate custom resource
apiVersion: config.openshift.io/v1 kind: FeatureGate metadata: name: cluster 1 # ... spec: featureSet: TechPreviewNoUpgrade 2
After you save the changes, new machine configs are created, the machine config pools are updated, and scheduling on each node is disabled while the change is being applied.
Verification
You can verify that the feature gates are enabled by looking at the kubelet.conf
file on a node after the nodes return to the ready state.
-
From the Administrator perspective in the web console, navigate to Compute
Nodes. - Select a node.
- In the Node details page, click Terminal.
In the terminal window, change your root directory to
/host
:sh-4.2# chroot /host
View the
kubelet.conf
file:sh-4.2# cat /etc/kubernetes/kubelet.conf
Sample output
# ... featureGates: InsightsOperatorPullingSCA: true, LegacyNodeRoleBehavior: false # ...
The features that are listed as
true
are enabled on your cluster.NoteThe features listed vary depending upon the OpenShift Container Platform version.
6.11.3. Enabling feature sets using the CLI
You can use the OpenShift CLI (oc
) to enable feature sets for all of the nodes in a cluster by editing the FeatureGate
custom resource (CR).
Prerequisites
-
You have installed the OpenShift CLI (
oc
).
Procedure
To enable feature sets:
Edit the
FeatureGate
CR namedcluster
:$ oc edit featuregate cluster
WarningEnabling the
TechPreviewNoUpgrade
feature set on your cluster cannot be undone and prevents minor version updates. You should not enable this feature set on production clusters.Sample FeatureGate custom resource
apiVersion: config.openshift.io/v1 kind: FeatureGate metadata: name: cluster 1 # ... spec: featureSet: TechPreviewNoUpgrade 2
After you save the changes, new machine configs are created, the machine config pools are updated, and scheduling on each node is disabled while the change is being applied.
Verification
You can verify that the feature gates are enabled by looking at the kubelet.conf
file on a node after the nodes return to the ready state.
-
From the Administrator perspective in the web console, navigate to Compute
Nodes. - Select a node.
- In the Node details page, click Terminal.
In the terminal window, change your root directory to
/host
:sh-4.2# chroot /host
View the
kubelet.conf
file:sh-4.2# cat /etc/kubernetes/kubelet.conf
Sample output
# ... featureGates: InsightsOperatorPullingSCA: true, LegacyNodeRoleBehavior: false # ...
The features that are listed as
true
are enabled on your cluster.NoteThe features listed vary depending upon the OpenShift Container Platform version.
6.12. etcd tasks
Back up etcd, enable or disable etcd encryption, or defragment etcd data.
6.12.1. About etcd encryption
By default, etcd data is not encrypted in OpenShift Container Platform. You can enable etcd encryption for your cluster to provide an additional layer of data security. For example, it can help protect the loss of sensitive data if an etcd backup is exposed to the incorrect parties.
When you enable etcd encryption, the following OpenShift API server and Kubernetes API server resources are encrypted:
- Secrets
- Config maps
- Routes
- OAuth access tokens
- OAuth authorize tokens
When you enable etcd encryption, encryption keys are created. You must have these keys to restore from an etcd backup.
Etcd encryption only encrypts values, not keys. Resource types, namespaces, and object names are unencrypted.
If etcd encryption is enabled during a backup, the static_kuberesources_<datetimestamp>.tar.gz
file contains the encryption keys for the etcd snapshot. For security reasons, store this file separately from the etcd snapshot. However, this file is required to restore a previous state of etcd from the respective etcd snapshot.
6.12.2. Supported encryption types
The following encryption types are supported for encrypting etcd data in OpenShift Container Platform:
- AES-CBC
- Uses AES-CBC with PKCS#7 padding and a 32 byte key to perform the encryption. The encryption keys are rotated weekly.
- AES-GCM
- Uses AES-GCM with a random nonce and a 32 byte key to perform the encryption. The encryption keys are rotated weekly.
6.12.3. Enabling etcd encryption
You can enable etcd encryption to encrypt sensitive resources in your cluster.
Do not back up etcd resources until the initial encryption process is completed. If the encryption process is not completed, the backup might be only partially encrypted.
After you enable etcd encryption, several changes can occur:
- The etcd encryption might affect the memory consumption of a few resources.
- You might notice a transient affect on backup performance because the leader must serve the backup.
- A disk I/O can affect the node that receives the backup state.
You can encrypt the etcd database in either AES-GCM or AES-CBC encryption.
To migrate your etcd database from one encryption type to the other, you can modify the API server’s spec.encryption.type
field. Migration of the etcd data to the new encryption type occurs automatically.
Prerequisites
-
Access to the cluster as a user with the
cluster-admin
role.
Procedure
Modify the
APIServer
object:$ oc edit apiserver
Set the
spec.encryption.type
field toaesgcm
oraescbc
:spec: encryption: type: aesgcm 1
- 1
- Set to
aesgcm
for AES-GCM encryption oraescbc
for AES-CBC encryption.
Save the file to apply the changes.
The encryption process starts. It can take 20 minutes or longer for this process to complete, depending on the size of the etcd database.
Verify that etcd encryption was successful.
Review the
Encrypted
status condition for the OpenShift API server to verify that its resources were successfully encrypted:$ oc get openshiftapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'
The output shows
EncryptionCompleted
upon successful encryption:EncryptionCompleted All resources encrypted: routes.route.openshift.io
If the output shows
EncryptionInProgress
, encryption is still in progress. Wait a few minutes and try again.Review the
Encrypted
status condition for the Kubernetes API server to verify that its resources were successfully encrypted:$ oc get kubeapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'
The output shows
EncryptionCompleted
upon successful encryption:EncryptionCompleted All resources encrypted: secrets, configmaps
If the output shows
EncryptionInProgress
, encryption is still in progress. Wait a few minutes and try again.Review the
Encrypted
status condition for the OpenShift OAuth API server to verify that its resources were successfully encrypted:$ oc get authentication.operator.openshift.io -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'
The output shows
EncryptionCompleted
upon successful encryption:EncryptionCompleted All resources encrypted: oauthaccesstokens.oauth.openshift.io, oauthauthorizetokens.oauth.openshift.io
If the output shows
EncryptionInProgress
, encryption is still in progress. Wait a few minutes and try again.
6.12.4. Disabling etcd encryption
You can disable encryption of etcd data in your cluster.
Prerequisites
-
Access to the cluster as a user with the
cluster-admin
role.
Procedure
Modify the
APIServer
object:$ oc edit apiserver
Set the
encryption
field type toidentity
:spec: encryption: type: identity 1
- 1
- The
identity
type is the default value and means that no encryption is performed.
Save the file to apply the changes.
The decryption process starts. It can take 20 minutes or longer for this process to complete, depending on the size of your cluster.
Verify that etcd decryption was successful.
Review the
Encrypted
status condition for the OpenShift API server to verify that its resources were successfully decrypted:$ oc get openshiftapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'
The output shows
DecryptionCompleted
upon successful decryption:DecryptionCompleted Encryption mode set to identity and everything is decrypted
If the output shows
DecryptionInProgress
, decryption is still in progress. Wait a few minutes and try again.Review the
Encrypted
status condition for the Kubernetes API server to verify that its resources were successfully decrypted:$ oc get kubeapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'
The output shows
DecryptionCompleted
upon successful decryption:DecryptionCompleted Encryption mode set to identity and everything is decrypted
If the output shows
DecryptionInProgress
, decryption is still in progress. Wait a few minutes and try again.Review the
Encrypted
status condition for the OpenShift OAuth API server to verify that its resources were successfully decrypted:$ oc get authentication.operator.openshift.io -o=jsonpath='{range .items[0].status.conditions[?(@.type=="Encrypted")]}{.reason}{"\n"}{.message}{"\n"}'
The output shows
DecryptionCompleted
upon successful decryption:DecryptionCompleted Encryption mode set to identity and everything is decrypted
If the output shows
DecryptionInProgress
, decryption is still in progress. Wait a few minutes and try again.
6.12.5. Backing up etcd data
Follow these steps to back up etcd data by creating an etcd snapshot and backing up the resources for the static pods. This backup can be saved and used at a later time if you need to restore etcd.
Only save a backup from a single control plane host. Do not take a backup from each control plane host in the cluster.
Prerequisites
-
You have access to the cluster as a user with the
cluster-admin
role. You have checked whether the cluster-wide proxy is enabled.
TipYou can check whether the proxy is enabled by reviewing the output of
oc get proxy cluster -o yaml
. The proxy is enabled if thehttpProxy
,httpsProxy
, andnoProxy
fields have values set.
Procedure
Start a debug session as root for a control plane node:
$ oc debug --as-root node/<node_name>
Change your root directory to
/host
in the debug shell:sh-4.4# chroot /host
If the cluster-wide proxy is enabled, export the
NO_PROXY
,HTTP_PROXY
, andHTTPS_PROXY
environment variables by running the following commands:$ export HTTP_PROXY=http://<your_proxy.example.com>:8080
$ export HTTPS_PROXY=https://<your_proxy.example.com>:8080
$ export NO_PROXY=<example.com>
Run the
cluster-backup.sh
script in the debug shell and pass in the location to save the backup to.TipThe
cluster-backup.sh
script is maintained as a component of the etcd Cluster Operator and is a wrapper around theetcdctl snapshot save
command.sh-4.4# /usr/local/bin/cluster-backup.sh /home/core/assets/backup
Example script output
found latest kube-apiserver: /etc/kubernetes/static-pod-resources/kube-apiserver-pod-6 found latest kube-controller-manager: /etc/kubernetes/static-pod-resources/kube-controller-manager-pod-7 found latest kube-scheduler: /etc/kubernetes/static-pod-resources/kube-scheduler-pod-6 found latest etcd: /etc/kubernetes/static-pod-resources/etcd-pod-3 ede95fe6b88b87ba86a03c15e669fb4aa5bf0991c180d3c6895ce72eaade54a1 etcdctl version: 3.4.14 API version: 3.4 {"level":"info","ts":1624647639.0188997,"caller":"snapshot/v3_snapshot.go:119","msg":"created temporary db file","path":"/home/core/assets/backup/snapshot_2021-06-25_190035.db.part"} {"level":"info","ts":"2021-06-25T19:00:39.030Z","caller":"clientv3/maintenance.go:200","msg":"opened snapshot stream; downloading"} {"level":"info","ts":1624647639.0301006,"caller":"snapshot/v3_snapshot.go:127","msg":"fetching snapshot","endpoint":"https://10.0.0.5:2379"} {"level":"info","ts":"2021-06-25T19:00:40.215Z","caller":"clientv3/maintenance.go:208","msg":"completed snapshot read; closing"} {"level":"info","ts":1624647640.6032252,"caller":"snapshot/v3_snapshot.go:142","msg":"fetched snapshot","endpoint":"https://10.0.0.5:2379","size":"114 MB","took":1.584090459} {"level":"info","ts":1624647640.6047094,"caller":"snapshot/v3_snapshot.go:152","msg":"saved","path":"/home/core/assets/backup/snapshot_2021-06-25_190035.db"} Snapshot saved at /home/core/assets/backup/snapshot_2021-06-25_190035.db {"hash":3866667823,"revision":31407,"totalKey":12828,"totalSize":114446336} snapshot db and kube resources are successfully saved to /home/core/assets/backup
In this example, two files are created in the
/home/core/assets/backup/
directory on the control plane host:-
snapshot_<datetimestamp>.db
: This file is the etcd snapshot. Thecluster-backup.sh
script confirms its validity. static_kuberesources_<datetimestamp>.tar.gz
: This file contains the resources for the static pods. If etcd encryption is enabled, it also contains the encryption keys for the etcd snapshot.NoteIf etcd encryption is enabled, it is recommended to store this second file separately from the etcd snapshot for security reasons. However, this file is required to restore from the etcd snapshot.
Keep in mind that etcd encryption only encrypts values, not keys. This means that resource types, namespaces, and object names are unencrypted.
-
6.12.6. Defragmenting etcd data
For large and dense clusters, etcd can suffer from poor performance if the keyspace grows too large and exceeds the space quota. Periodically maintain and defragment etcd to free up space in the data store. Monitor Prometheus for etcd metrics and defragment it when required; otherwise, etcd can raise a cluster-wide alarm that puts the cluster into a maintenance mode that accepts only key reads and deletes.
Monitor these key metrics:
-
etcd_server_quota_backend_bytes
, which is the current quota limit -
etcd_mvcc_db_total_size_in_use_in_bytes
, which indicates the actual database usage after a history compaction -
etcd_mvcc_db_total_size_in_bytes
, which shows the database size, including free space waiting for defragmentation
Defragment etcd data to reclaim disk space after events that cause disk fragmentation, such as etcd history compaction.
History compaction is performed automatically every five minutes and leaves gaps in the back-end database. This fragmented space is available for use by etcd, but is not available to the host file system. You must defragment etcd to make this space available to the host file system.
Defragmentation occurs automatically, but you can also trigger it manually.
Automatic defragmentation is good for most cases, because the etcd operator uses cluster information to determine the most efficient operation for the user.
6.12.6.1. Automatic defragmentation
The etcd Operator automatically defragments disks. No manual intervention is needed.
Verify that the defragmentation process is successful by viewing one of these logs:
- etcd logs
- cluster-etcd-operator pod
- operator status error log
Automatic defragmentation can cause leader election failure in various OpenShift core components, such as the Kubernetes controller manager, which triggers a restart of the failing component. The restart is harmless and either triggers failover to the next running instance or the component resumes work again after the restart.
Example log output for successful defragmentation
etcd member has been defragmented: <member_name>, memberID: <member_id>
Example log output for unsuccessful defragmentation
failed defrag on member: <member_name>, memberID: <member_id>: <error_message>
6.12.6.2. Manual defragmentation
A Prometheus alert indicates when you need to use manual defragmentation. The alert is displayed in two cases:
- When etcd uses more than 50% of its available space for more than 10 minutes
- When etcd is actively using less than 50% of its total database size for more than 10 minutes
You can also determine whether defragmentation is needed by checking the etcd database size in MB that will be freed by defragmentation with the PromQL expression: (etcd_mvcc_db_total_size_in_bytes - etcd_mvcc_db_total_size_in_use_in_bytes)/1024/1024
Defragmenting etcd is a blocking action. The etcd member will not respond until defragmentation is complete. For this reason, wait at least one minute between defragmentation actions on each of the pods to allow the cluster to recover.
Follow this procedure to defragment etcd data on each etcd member.
Prerequisites
-
You have access to the cluster as a user with the
cluster-admin
role.
Procedure
Determine which etcd member is the leader, because the leader should be defragmented last.
Get the list of etcd pods:
$ oc -n openshift-etcd get pods -l k8s-app=etcd -o wide
Example output
etcd-ip-10-0-159-225.example.redhat.com 3/3 Running 0 175m 10.0.159.225 ip-10-0-159-225.example.redhat.com <none> <none> etcd-ip-10-0-191-37.example.redhat.com 3/3 Running 0 173m 10.0.191.37 ip-10-0-191-37.example.redhat.com <none> <none> etcd-ip-10-0-199-170.example.redhat.com 3/3 Running 0 176m 10.0.199.170 ip-10-0-199-170.example.redhat.com <none> <none>
Choose a pod and run the following command to determine which etcd member is the leader:
$ oc rsh -n openshift-etcd etcd-ip-10-0-159-225.example.redhat.com etcdctl endpoint status --cluster -w table
Example output
Defaulting container name to etcdctl. Use 'oc describe pod/etcd-ip-10-0-159-225.example.redhat.com -n openshift-etcd' to see all of the containers in this pod. +---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ | ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS | +---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ | https://10.0.191.37:2379 | 251cd44483d811c3 | 3.5.9 | 104 MB | false | false | 7 | 91624 | 91624 | | | https://10.0.159.225:2379 | 264c7c58ecbdabee | 3.5.9 | 104 MB | false | false | 7 | 91624 | 91624 | | | https://10.0.199.170:2379 | 9ac311f93915cc79 | 3.5.9 | 104 MB | true | false | 7 | 91624 | 91624 | | +---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
Based on the
IS LEADER
column of this output, thehttps://10.0.199.170:2379
endpoint is the leader. Matching this endpoint with the output of the previous step, the pod name of the leader isetcd-ip-10-0-199-170.example.redhat.com
.
Defragment an etcd member.
Connect to the running etcd container, passing in the name of a pod that is not the leader:
$ oc rsh -n openshift-etcd etcd-ip-10-0-159-225.example.redhat.com
Unset the
ETCDCTL_ENDPOINTS
environment variable:sh-4.4# unset ETCDCTL_ENDPOINTS
Defragment the etcd member:
sh-4.4# etcdctl --command-timeout=30s --endpoints=https://localhost:2379 defrag
Example output
Finished defragmenting etcd member[https://localhost:2379]
If a timeout error occurs, increase the value for
--command-timeout
until the command succeeds.Verify that the database size was reduced:
sh-4.4# etcdctl endpoint status -w table --cluster
Example output
+---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ | ENDPOINT | ID | VERSION | DB SIZE | IS LEADER | IS LEARNER | RAFT TERM | RAFT INDEX | RAFT APPLIED INDEX | ERRORS | +---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+ | https://10.0.191.37:2379 | 251cd44483d811c3 | 3.5.9 | 104 MB | false | false | 7 | 91624 | 91624 | | | https://10.0.159.225:2379 | 264c7c58ecbdabee | 3.5.9 | 41 MB | false | false | 7 | 91624 | 91624 | | 1 | https://10.0.199.170:2379 | 9ac311f93915cc79 | 3.5.9 | 104 MB | true | false | 7 | 91624 | 91624 | | +---------------------------+------------------+---------+---------+-----------+------------+-----------+------------+--------------------+--------+
This example shows that the database size for this etcd member is now 41 MB as opposed to the starting size of 104 MB.
Repeat these steps to connect to each of the other etcd members and defragment them. Always defragment the leader last.
Wait at least one minute between defragmentation actions to allow the etcd pod to recover. Until the etcd pod recovers, the etcd member will not respond.
If any
NOSPACE
alarms were triggered due to the space quota being exceeded, clear them.Check if there are any
NOSPACE
alarms:sh-4.4# etcdctl alarm list
Example output
memberID:12345678912345678912 alarm:NOSPACE
Clear the alarms:
sh-4.4# etcdctl alarm disarm
6.12.7. Restoring to a previous cluster state
You can use a saved etcd backup to restore a previous cluster state or restore a cluster that has lost the majority of control plane hosts.
If your cluster uses a control plane machine set, see "Troubleshooting the control plane machine set" for a more simple etcd recovery procedure.
When you restore your cluster, you must use an etcd backup that was taken from the same z-stream release. For example, an OpenShift Container Platform 4.7.2 cluster must use an etcd backup that was taken from 4.7.2.
Prerequisites
-
Access to the cluster as a user with the
cluster-admin
role through a certificate-basedkubeconfig
file, like the one that was used during installation. - A healthy control plane host to use as the recovery host.
- SSH access to control plane hosts.
-
A backup directory containing both the etcd snapshot and the resources for the static pods, which were from the same backup. The file names in the directory must be in the following formats:
snapshot_<datetimestamp>.db
andstatic_kuberesources_<datetimestamp>.tar.gz
.
For non-recovery control plane nodes, it is not required to establish SSH connectivity or to stop the static pods. You can delete and recreate other non-recovery, control plane machines, one by one.
Procedure
- Select a control plane host to use as the recovery host. This is the host that you will run the restore operation on.
Establish SSH connectivity to each of the control plane nodes, including the recovery host.
The Kubernetes API server becomes inaccessible after the restore process starts, so you cannot access the control plane nodes. For this reason, it is recommended to establish SSH connectivity to each control plane host in a separate terminal.
ImportantIf you do not complete this step, you will not be able to access the control plane hosts to complete the restore procedure, and you will be unable to recover your cluster from this state.
Copy the etcd backup directory to the recovery control plane host.
This procedure assumes that you copied the
backup
directory containing the etcd snapshot and the resources for the static pods to the/home/core/
directory of your recovery control plane host.Stop the static pods on any other control plane nodes.
NoteYou do not need to stop the static pods on the recovery host.
- Access a control plane host that is not the recovery host.
Move the existing etcd pod file out of the kubelet manifest directory:
$ sudo mv -v /etc/kubernetes/manifests/etcd-pod.yaml /tmp
Verify that the etcd pods are stopped.
$ sudo crictl ps | grep etcd | egrep -v "operator|etcd-guard"
The output of this command should be empty. If it is not empty, wait a few minutes and check again.
Move the existing Kubernetes API server pod file out of the kubelet manifest directory:
$ sudo mv -v /etc/kubernetes/manifests/kube-apiserver-pod.yaml /tmp
Verify that the Kubernetes API server pods are stopped.
$ sudo crictl ps | grep kube-apiserver | egrep -v "operator|guard"
The output of this command should be empty. If it is not empty, wait a few minutes and check again.
Move the etcd data directory to a different location:
$ sudo mv -v /var/lib/etcd/ /tmp
If the
/etc/kubernetes/manifests/keepalived.yaml
file exists and the node is deleted, follow these steps:Move the
/etc/kubernetes/manifests/keepalived.yaml
file out of the kubelet manifest directory:$ sudo mv -v /etc/kubernetes/manifests/keepalived.yaml /tmp
Verify that any containers managed by the
keepalived
daemon are stopped:$ sudo crictl ps --name keepalived
The output of this command should be empty. If it is not empty, wait a few minutes and check again.
Check if the control plane has any Virtual IPs (VIPs) assigned to it:
$ ip -o address | egrep '<api_vip>|<ingress_vip>'
For each reported VIP, run the following command to remove it:
$ sudo ip address del <reported_vip> dev <reported_vip_device>
- Repeat this step on each of the other control plane hosts that is not the recovery host.
- Access the recovery control plane host.
If the
keepalived
daemon is in use, verify that the recovery control plane node owns the VIP:$ ip -o address | grep <api_vip>
The address of the VIP is highlighted in the output if it exists. This command returns an empty string if the VIP is not set or configured incorrectly.
If the cluster-wide proxy is enabled, be sure that you have exported the
NO_PROXY
,HTTP_PROXY
, andHTTPS_PROXY
environment variables.TipYou can check whether the proxy is enabled by reviewing the output of
oc get proxy cluster -o yaml
. The proxy is enabled if thehttpProxy
,httpsProxy
, andnoProxy
fields have values set.Run the restore script on the recovery control plane host and pass in the path to the etcd backup directory:
$ sudo -E /usr/local/bin/cluster-restore.sh /home/core/assets/backup
Example script output
...stopping kube-scheduler-pod.yaml ...stopping kube-controller-manager-pod.yaml ...stopping etcd-pod.yaml ...stopping kube-apiserver-pod.yaml Waiting for container etcd to stop .complete Waiting for container etcdctl to stop .............................complete Waiting for container etcd-metrics to stop complete Waiting for container kube-controller-manager to stop complete Waiting for container kube-apiserver to stop ..........................................................................................complete Waiting for container kube-scheduler to stop complete Moving etcd data-dir /var/lib/etcd/member to /var/lib/etcd-backup starting restore-etcd static pod starting kube-apiserver-pod.yaml static-pod-resources/kube-apiserver-pod-7/kube-apiserver-pod.yaml starting kube-controller-manager-pod.yaml static-pod-resources/kube-controller-manager-pod-7/kube-controller-manager-pod.yaml starting kube-scheduler-pod.yaml static-pod-resources/kube-scheduler-pod-8/kube-scheduler-pod.yaml
NoteThe restore process can cause nodes to enter the
NotReady
state if the node certificates were updated after the last etcd backup.Check the nodes to ensure they are in the
Ready
state.Run the following command:
$ oc get nodes -w
Sample output
NAME STATUS ROLES AGE VERSION host-172-25-75-28 Ready master 3d20h v1.26.0 host-172-25-75-38 Ready infra,worker 3d20h v1.26.0 host-172-25-75-40 Ready master 3d20h v1.26.0 host-172-25-75-65 Ready master 3d20h v1.26.0 host-172-25-75-74 Ready infra,worker 3d20h v1.26.0 host-172-25-75-79 Ready worker 3d20h v1.26.0 host-172-25-75-86 Ready worker 3d20h v1.26.0 host-172-25-75-98 Ready infra,worker 3d20h v1.26.0
It can take several minutes for all nodes to report their state.
If any nodes are in the
NotReady
state, log in to the nodes and remove all of the PEM files from the/var/lib/kubelet/pki
directory on each node. You can SSH into the nodes or use the terminal window in the web console.$ ssh -i <ssh-key-path> core@<master-hostname>
Sample
pki
directorysh-4.4# pwd /var/lib/kubelet/pki sh-4.4# ls kubelet-client-2022-04-28-11-24-09.pem kubelet-server-2022-04-28-11-24-15.pem kubelet-client-current.pem kubelet-server-current.pem
Restart the kubelet service on all control plane hosts.
From the recovery host, run the following command:
$ sudo systemctl restart kubelet.service
- Repeat this step on all other control plane hosts.
Approve the pending CSRs:
NoteClusters with no worker nodes, such as single-node clusters or clusters consisting of three schedulable control plane nodes, will not have any pending CSRs to approve. You can skip all the commands listed in this step.
Get the list of current CSRs:
$ oc get csr
Example output
NAME AGE SIGNERNAME REQUESTOR CONDITION csr-2s94x 8m3s kubernetes.io/kubelet-serving system:node:<node_name> Pending 1 csr-4bd6t 8m3s kubernetes.io/kubelet-serving system:node:<node_name> Pending 2 csr-4hl85 13m kubernetes.io/kube-apiserver-client-kubelet system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending 3 csr-zhhhp 3m8s kubernetes.io/kube-apiserver-client-kubelet system:serviceaccount:openshift-machine-config-operator:node-bootstrapper Pending 4 ...
Review the details of a CSR to verify that it is valid:
$ oc describe csr <csr_name> 1
- 1
<csr_name>
is the name of a CSR from the list of current CSRs.
Approve each valid
node-bootstrapper
CSR:$ oc adm certificate approve <csr_name>
For user-provisioned installations, approve each valid kubelet service CSR:
$ oc adm certificate approve <csr_name>
Verify that the single member control plane has started successfully.
From the recovery host, verify that the etcd container is running.
$ sudo crictl ps | grep etcd | egrep -v "operator|etcd-guard"
Example output
3ad41b7908e32 36f86e2eeaaffe662df0d21041eb22b8198e0e58abeeae8c743c3e6e977e8009 About a minute ago Running etcd 0 7c05f8af362f0
From the recovery host, verify that the etcd pod is running.
$ oc -n openshift-etcd get pods -l k8s-app=etcd
Example output
NAME READY STATUS RESTARTS AGE etcd-ip-10-0-143-125.ec2.internal 1/1 Running 1 2m47s
If the status is
Pending
, or the output lists more than one running etcd pod, wait a few minutes and check again.
If you are using the
OVNKubernetes
network plugin, delete the node objects that are associated with control plane hosts that are not the recovery control plane host.$ oc delete node <non-recovery-controlplane-host-1> <non-recovery-controlplane-host-2>
Verify that the Cluster Network Operator (CNO) redeploys the OVN-Kubernetes control plane and that it no longer references the non-recovery controller IP addresses. To verify this result, regularly check the output of the following command. Wait until it returns an empty result before you proceed to restart the Open Virtual Network (OVN) Kubernetes pods on all of the hosts in the next step.
$ oc -n openshift-ovn-kubernetes get ds/ovnkube-master -o yaml | grep -E '<non-recovery_controller_ip_1>|<non-recovery_controller_ip_2>'
NoteIt can take at least 5-10 minutes for the OVN-Kubernetes control plane to be redeployed and the previous command to return empty output.
If you are using the OVN-Kubernetes network plugin, restart the Open Virtual Network (OVN) Kubernetes pods on all of the hosts.
NoteValidating and mutating admission webhooks can reject pods. If you add any additional webhooks with the
failurePolicy
set toFail
, then they can reject pods and the restoration process can fail. You can avoid this by saving and deleting webhooks while restoring the cluster state. After the cluster state is restored successfully, you can enable the webhooks again.Alternatively, you can temporarily set the
failurePolicy
toIgnore
while restoring the cluster state. After the cluster state is restored successfully, you can set thefailurePolicy
toFail
.Remove the northbound database (nbdb) and southbound database (sbdb). Access the recovery host and the remaining control plane nodes by using Secure Shell (SSH) and run the following command:
$ sudo rm -f /var/lib/ovn/etc/*.db
Delete all OVN-Kubernetes control plane pods by running the following command:
$ oc delete pods -l app=ovnkube-master -n openshift-ovn-kubernetes
Ensure that any OVN-Kubernetes control plane pods are deployed again and are in a
Running
state by running the following command:$ oc get pods -l app=ovnkube-master -n openshift-ovn-kubernetes
Example output
NAME READY STATUS RESTARTS AGE ovnkube-master-nb24h 4/4 Running 0 48s
Delete all
ovnkube-node
pods by running the following command:$ oc get pods -n openshift-ovn-kubernetes -o name | grep ovnkube-node | while read p ; do oc delete $p -n openshift-ovn-kubernetes ; done
Ensure that all the
ovnkube-node
pods are deployed again and are in aRunning
state by running the following command:$ oc get pods -n openshift-ovn-kubernetes | grep ovnkube-node
Delete and re-create other non-recovery, control plane machines, one by one. After the machines are re-created, a new revision is forced and etcd automatically scales up.
If you use a user-provisioned bare metal installation, you can re-create a control plane machine by using the same method that you used to originally create it. For more information, see "Installing a user-provisioned cluster on bare metal".
WarningDo not delete and re-create the machine for the recovery host.
If you are running installer-provisioned infrastructure, or you used the Machine API to create your machines, follow these steps:
WarningDo not delete and re-create the machine for the recovery host.
For bare metal installations on installer-provisioned infrastructure, control plane machines are not re-created. For more information, see "Replacing a bare-metal control plane node".
Obtain the machine for one of the lost control plane hosts.
In a terminal that has access to the cluster as a cluster-admin user, run the following command:
$ oc get machines -n openshift-machine-api -o wide
Example output:
NAME PHASE TYPE REGION ZONE AGE NODE PROVIDERID STATE clustername-8qw5l-master-0 Running m4.xlarge us-east-1 us-east-1a 3h37m ip-10-0-131-183.ec2.internal aws:///us-east-1a/i-0ec2782f8287dfb7e stopped 1 clustername-8qw5l-master-1 Running m4.xlarge us-east-1 us-east-1b 3h37m ip-10-0-143-125.ec2.internal aws:///us-east-1b/i-096c349b700a19631 running clustername-8qw5l-master-2 Running m4.xlarge us-east-1 us-east-1c 3h37m ip-10-0-154-194.ec2.internal aws:///us-east-1c/i-02626f1dba9ed5bba running clustername-8qw5l-worker-us-east-1a-wbtgd Running m4.large us-east-1 us-east-1a 3h28m ip-10-0-129-226.ec2.internal aws:///us-east-1a/i-010ef6279b4662ced running clustername-8qw5l-worker-us-east-1b-lrdxb Running m4.large us-east-1 us-east-1b 3h28m ip-10-0-144-248.ec2.internal aws:///us-east-1b/i-0cb45ac45a166173b running clustername-8qw5l-worker-us-east-1c-pkg26 Running m4.large us-east-1 us-east-1c 3h28m ip-10-0-170-181.ec2.internal aws:///us-east-1c/i-06861c00007751b0a running
- 1
- This is the control plane machine for the lost control plane host,
ip-10-0-131-183.ec2.internal
.
Delete the machine of the lost control plane host by running:
$ oc delete machine -n openshift-machine-api clustername-8qw5l-master-0 1
- 1
- Specify the name of the control plane machine for the lost control plane host.
A new machine is automatically provisioned after deleting the machine of the lost control plane host.
Verify that a new machine has been created by running:
$ oc get machines -n openshift-machine-api -o wide
Example output:
NAME PHASE TYPE REGION ZONE AGE NODE PROVIDERID STATE clustername-8qw5l-master-1 Running m4.xlarge us-east-1 us-east-1b 3h37m ip-10-0-143-125.ec2.internal aws:///us-east-1b/i-096c349b700a19631 running clustername-8qw5l-master-2 Running m4.xlarge us-east-1 us-east-1c 3h37m ip-10-0-154-194.ec2.internal aws:///us-east-1c/i-02626f1dba9ed5bba running clustername-8qw5l-master-3 Provisioning m4.xlarge us-east-1 us-east-1a 85s ip-10-0-173-171.ec2.internal aws:///us-east-1a/i-015b0888fe17bc2c8 running 1 clustername-8qw5l-worker-us-east-1a-wbtgd Running m4.large us-east-1 us-east-1a 3h28m ip-10-0-129-226.ec2.internal aws:///us-east-1a/i-010ef6279b4662ced running clustername-8qw5l-worker-us-east-1b-lrdxb Running m4.large us-east-1 us-east-1b 3h28m ip-10-0-144-248.ec2.internal aws:///us-east-1b/i-0cb45ac45a166173b running clustername-8qw5l-worker-us-east-1c-pkg26 Running m4.large us-east-1 us-east-1c 3h28m ip-10-0-170-181.ec2.internal aws:///us-east-1c/i-06861c00007751b0a running
- 1
- The new machine,
clustername-8qw5l-master-3
is being created and is ready after the phase changes fromProvisioning
toRunning
.
It might take a few minutes for the new machine to be created. The etcd cluster Operator will automatically sync when the machine or node returns to a healthy state.
- Repeat these steps for each lost control plane host that is not the recovery host.
Turn off the quorum guard by entering the following command:
$ oc patch etcd/cluster --type=merge -p '{"spec": {"unsupportedConfigOverrides": {"useUnsupportedUnsafeNonHANonProductionUnstableEtcd": true}}}'
This command ensures that you can successfully re-create secrets and roll out the static pods.
In a separate terminal window within the recovery host, export the recovery
kubeconfig
file by running the following command:$ export KUBECONFIG=/etc/kubernetes/static-pod-resources/kube-apiserver-certs/secrets/node-kubeconfigs/localhost-recovery.kubeconfig
Force etcd redeployment.
In the same terminal window where you exported the recovery
kubeconfig
file, run the following command:$ oc patch etcd cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge 1
- 1
- The
forceRedeploymentReason
value must be unique, which is why a timestamp is appended.
When the etcd cluster Operator performs a redeployment, the existing nodes are started with new pods similar to the initial bootstrap scale up.
Turn the quorum guard back on by entering the following command:
$ oc patch etcd/cluster --type=merge -p '{"spec": {"unsupportedConfigOverrides": null}}'
You can verify that the
unsupportedConfigOverrides
section is removed from the object by entering this command:$ oc get etcd/cluster -oyaml
Verify all nodes are updated to the latest revision.
In a terminal that has access to the cluster as a
cluster-admin
user, run the following command:$ oc get etcd -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'
Review the
NodeInstallerProgressing
status condition for etcd to verify that all nodes are at the latest revision. The output showsAllNodesAtLatestRevision
upon successful update:AllNodesAtLatestRevision 3 nodes are at revision 7 1
- 1
- In this example, the latest revision number is
7
.
If the output includes multiple revision numbers, such as
2 nodes are at revision 6; 1 nodes are at revision 7
, this means that the update is still in progress. Wait a few minutes and try again.After etcd is redeployed, force new rollouts for the control plane. The Kubernetes API server will reinstall itself on the other nodes because the kubelet is connected to API servers using an internal load balancer.
In a terminal that has access to the cluster as a
cluster-admin
user, run the following commands.Force a new rollout for the Kubernetes API server:
$ oc patch kubeapiserver cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge
Verify all nodes are updated to the latest revision.
$ oc get kubeapiserver -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'
Review the
NodeInstallerProgressing
status condition to verify that all nodes are at the latest revision. The output showsAllNodesAtLatestRevision
upon successful update:AllNodesAtLatestRevision 3 nodes are at revision 7 1
- 1
- In this example, the latest revision number is
7
.
If the output includes multiple revision numbers, such as
2 nodes are at revision 6; 1 nodes are at revision 7
, this means that the update is still in progress. Wait a few minutes and try again.Force a new rollout for the Kubernetes controller manager:
$ oc patch kubecontrollermanager cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge
Verify all nodes are updated to the latest revision.
$ oc get kubecontrollermanager -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'
Review the
NodeInstallerProgressing
status condition to verify that all nodes are at the latest revision. The output showsAllNodesAtLatestRevision
upon successful update:AllNodesAtLatestRevision 3 nodes are at revision 7 1
- 1
- In this example, the latest revision number is
7
.
If the output includes multiple revision numbers, such as
2 nodes are at revision 6; 1 nodes are at revision 7
, this means that the update is still in progress. Wait a few minutes and try again.Force a new rollout for the Kubernetes scheduler:
$ oc patch kubescheduler cluster -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date --rfc-3339=ns )"'"}}' --type=merge
Verify all nodes are updated to the latest revision.
$ oc get kubescheduler -o=jsonpath='{range .items[0].status.conditions[?(@.type=="NodeInstallerProgressing")]}{.reason}{"\n"}{.message}{"\n"}'
Review the
NodeInstallerProgressing
status condition to verify that all nodes are at the latest revision. The output showsAllNodesAtLatestRevision
upon successful update:AllNodesAtLatestRevision 3 nodes are at revision 7 1
- 1
- In this example, the latest revision number is
7
.
If the output includes multiple revision numbers, such as
2 nodes are at revision 6; 1 nodes are at revision 7
, this means that the update is still in progress. Wait a few minutes and try again.
Verify that all control plane hosts have started and joined the cluster.
In a terminal that has access to the cluster as a
cluster-admin
user, run the following command:$ oc -n openshift-etcd get pods -l k8s-app=etcd
Example output
etcd-ip-10-0-143-125.ec2.internal 2/2 Running 0 9h etcd-ip-10-0-154-194.ec2.internal 2/2 Running 0 9h etcd-ip-10-0-173-171.ec2.internal 2/2 Running 0 9h
To ensure that all workloads return to normal operation following a recovery procedure, restart each pod that stores Kubernetes API information. This includes OpenShift Container Platform components such as routers, Operators, and third-party components.
On completion of the previous procedural steps, you might need to wait a few minutes for all services to return to their restored state. For example, authentication by using oc login
might not immediately work until the OAuth server pods are restarted.
Consider using the system:admin
kubeconfig
file for immediate authentication. This method basis its authentication on SSL/TLS client certificates as against OAuth tokens. You can authenticate with this file by issuing the following command:
$ export KUBECONFIG=<installation_directory>/auth/kubeconfig
Issue the following command to display your authenticated user name:
$ oc whoami
6.12.8. Issues and workarounds for restoring a persistent storage state
If your OpenShift Container Platform cluster uses persistent storage of any form, a state of the cluster is typically stored outside etcd. It might be an Elasticsearch cluster running in a pod or a database running in a StatefulSet
object. When you restore from an etcd backup, the status of the workloads in OpenShift Container Platform is also restored. However, if the etcd snapshot is old, the status might be invalid or outdated.
The contents of persistent volumes (PVs) are never part of the etcd snapshot. When you restore an OpenShift Container Platform cluster from an etcd snapshot, non-critical workloads might gain access to critical data, or vice-versa.
The following are some example scenarios that produce an out-of-date status:
- MySQL database is running in a pod backed up by a PV object. Restoring OpenShift Container Platform from an etcd snapshot does not bring back the volume on the storage provider, and does not produce a running MySQL pod, despite the pod repeatedly attempting to start. You must manually restore this pod by restoring the volume on the storage provider, and then editing the PV to point to the new volume.
- Pod P1 is using volume A, which is attached to node X. If the etcd snapshot is taken while another pod uses the same volume on node Y, then when the etcd restore is performed, pod P1 might not be able to start correctly due to the volume still being attached to node Y. OpenShift Container Platform is not aware of the attachment, and does not automatically detach it. When this occurs, the volume must be manually detached from node Y so that the volume can attach on node X, and then pod P1 can start.
- Cloud provider or storage provider credentials were updated after the etcd snapshot was taken. This causes any CSI drivers or Operators that depend on the those credentials to not work. You might have to manually update the credentials required by those drivers or Operators.
A device is removed or renamed from OpenShift Container Platform nodes after the etcd snapshot is taken. The Local Storage Operator creates symlinks for each PV that it manages from
/dev/disk/by-id
or/dev
directories. This situation might cause the local PVs to refer to devices that no longer exist.To fix this problem, an administrator must:
- Manually remove the PVs with invalid devices.
- Remove symlinks from respective nodes.
-
Delete
LocalVolume
orLocalVolumeSet
objects (see StorageConfiguring persistent storage Persistent storage using local volumes Deleting the Local Storage Operator Resources).
6.13. Pod disruption budgets
Understand and configure pod disruption budgets.
6.13.1. Understanding how to use pod disruption budgets to specify the number of pods that must be up
A pod disruption budget allows the specification of safety constraints on pods during operations, such as draining a node for maintenance.
PodDisruptionBudget
is an API object that specifies the minimum number or percentage of replicas that must be up at a time. Setting these in projects can be helpful during node maintenance (such as scaling a cluster down or a cluster upgrade) and is only honored on voluntary evictions (not on node failures).
A PodDisruptionBudget
object’s configuration consists of the following key parts:
- A label selector, which is a label query over a set of pods.
An availability level, which specifies the minimum number of pods that must be available simultaneously, either:
-
minAvailable
is the number of pods must always be available, even during a disruption. -
maxUnavailable
is the number of pods can be unavailable during a disruption.
-
Available
refers to the number of pods that has condition Ready=True
. Ready=True
refers to the pod that is able to serve requests and should be added to the load balancing pools of all matching services.
A maxUnavailable
of 0%
or 0
or a minAvailable
of 100%
or equal to the number of replicas is permitted but can block nodes from being drained.
The default setting for maxUnavailable
is 1
for all the machine config pools in OpenShift Container Platform. It is recommended to not change this value and update one control plane node at a time. Do not change this value to 3
for the control plane pool.
You can check for pod disruption budgets across all projects with the following:
$ oc get poddisruptionbudget --all-namespaces
Example output
NAMESPACE NAME MIN AVAILABLE MAX UNAVAILABLE ALLOWED DISRUPTIONS AGE openshift-apiserver openshift-apiserver-pdb N/A 1 1 121m openshift-cloud-controller-manager aws-cloud-controller-manager 1 N/A 1 125m openshift-cloud-credential-operator pod-identity-webhook 1 N/A 1 117m openshift-cluster-csi-drivers aws-ebs-csi-driver-controller-pdb N/A 1 1 121m openshift-cluster-storage-operator csi-snapshot-controller-pdb N/A 1 1 122m openshift-cluster-storage-operator csi-snapshot-webhook-pdb N/A 1 1 122m openshift-console console N/A 1 1 116m #...
The PodDisruptionBudget
is considered healthy when there are at least minAvailable
pods running in the system. Every pod above that limit can be evicted.
Depending on your pod priority and preemption settings, lower-priority pods might be removed despite their pod disruption budget requirements.
6.13.2. Specifying the number of pods that must be up with pod disruption budgets
You can use a PodDisruptionBudget
object to specify the minimum number or percentage of replicas that must be up at a time.
Procedure
To configure a pod disruption budget:
Create a YAML file with the an object definition similar to the following:
apiVersion: policy/v1 1 kind: PodDisruptionBudget metadata: name: my-pdb spec: minAvailable: 2 2 selector: 3 matchLabels: name: my-pod
- 1
PodDisruptionBudget
is part of thepolicy/v1
API group.- 2
- The minimum number of pods that must be available simultaneously. This can be either an integer or a string specifying a percentage, for example,
20%
. - 3
- A label query over a set of resources. The result of
matchLabels
andmatchExpressions
are logically conjoined. Leave this parameter blank, for exampleselector {}
, to select all pods in the project.
Or:
apiVersion: policy/v1 1 kind: PodDisruptionBudget metadata: name: my-pdb spec: maxUnavailable: 25% 2 selector: 3 matchLabels: name: my-pod
- 1
PodDisruptionBudget
is part of thepolicy/v1
API group.- 2
- The maximum number of pods that can be unavailable simultaneously. This can be either an integer or a string specifying a percentage, for example,
20%
. - 3
- A label query over a set of resources. The result of
matchLabels
andmatchExpressions
are logically conjoined. Leave this parameter blank, for exampleselector {}
, to select all pods in the project.
Run the following command to add the object to project:
$ oc create -f </path/to/file> -n <project_name>
6.13.3. Specifying the eviction policy for unhealthy pods
When you use pod disruption budgets (PDBs) to specify how many pods must be available simultaneously, you can also define the criteria for how unhealthy pods are considered for eviction.
You can choose one of the following policies:
- IfHealthyBudget
- Running pods that are not yet healthy can be evicted only if the guarded application is not disrupted.
- AlwaysAllow
-
Running pods that are not yet healthy can be evicted regardless of whether the criteria in the pod disruption budget is met. This policy can help evict malfunctioning applications, such as ones with pods stuck in the
CrashLoopBackOff
state or failing to report theReady
status.
Specifying the unhealthy pod eviction policy for pod disruption budgets is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
To use this Technology Preview feature, you must have enabled the TechPreviewNoUpgrade
feature set.
Enabling the TechPreviewNoUpgrade
feature set on your cluster cannot be undone and prevents minor version updates. You should not enable this feature set on production clusters.
Procedure
Create a YAML file that defines a
PodDisruptionBudget
object and specify the unhealthy pod eviction policy:Example
pod-disruption-budget.yaml
fileapiVersion: policy/v1 kind: PodDisruptionBudget metadata: name: my-pdb spec: minAvailable: 2 selector: matchLabels: name: my-pod unhealthyPodEvictionPolicy: AlwaysAllow 1
- 1
- Choose either
IfHealthyBudget
orAlwaysAllow
as the unhealthy pod eviction policy. The default isIfHealthyBudget
when theunhealthyPodEvictionPolicy
field is empty.
Create the
PodDisruptionBudget
object by running the following command:$ oc create -f pod-disruption-budget.yaml
With a PDB that has the AlwaysAllow
unhealthy pod eviction policy set, you can now drain nodes and evict the pods for a malfunctioning application guarded by this PDB.
Additional resources
- Enabling features using feature gates
- Unhealthy Pod Eviction Policy in the Kubernetes documentation
6.14. Rotating or removing cloud provider credentials
After installing OpenShift Container Platform, some organizations require the rotation or removal of the cloud provider credentials that were used during the initial installation.
To allow the cluster to use the new credentials, you must update the secrets that the Cloud Credential Operator (CCO) uses to manage cloud provider credentials.
6.14.1. Rotating cloud provider credentials with the Cloud Credential Operator utility
The Cloud Credential Operator (CCO) utility ccoctl
supports updating secrets for clusters installed on IBM Cloud.
6.14.1.1. Rotating API keys
You can rotate API keys for your existing service IDs and update the corresponding secrets.
Prerequisites
-
You have configured the
ccoctl
binary. - You have existing service IDs in a live OpenShift Container Platform cluster installed.
Procedure
Use the
ccoctl
utility to rotate your API keys for the service IDs and update the secrets:$ ccoctl <provider_name> refresh-keys \ 1 --kubeconfig <openshift_kubeconfig_file> \ 2 --credentials-requests-dir <path_to_credential_requests_directory> \ 3 --name <name> 4
NoteIf your cluster uses Technology Preview features that are enabled by the
TechPreviewNoUpgrade
feature set, you must include the--enable-tech-preview
parameter.
6.14.2. Rotating cloud provider credentials manually
If your cloud provider credentials are changed for any reason, you must manually update the secret that the Cloud Credential Operator (CCO) uses to manage cloud provider credentials.
The process for rotating cloud credentials depends on the mode that the CCO is configured to use. After you rotate credentials for a cluster that is using mint mode, you must manually remove the component credentials that were created by the removed credential.
Prerequisites
Your cluster is installed on a platform that supports rotating cloud credentials manually with the CCO mode that you are using:
- For mint mode, Amazon Web Services (AWS) and Google Cloud Platform (GCP) are supported.
- For passthrough mode, Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform (GCP), Red Hat OpenStack Platform (RHOSP), Red Hat Virtualization (RHV), and VMware vSphere are supported.
- You have changed the credentials that are used to interface with your cloud provider.
- The new credentials have sufficient permissions for the mode CCO is configured to use in your cluster.
Procedure
-
In the Administrator perspective of the web console, navigate to Workloads
Secrets. In the table on the Secrets page, find the root secret for your cloud provider.
Platform Secret name AWS
aws-creds
Azure
azure-credentials
GCP
gcp-credentials
RHOSP
openstack-credentials
RHV
ovirt-credentials
VMware vSphere
vsphere-creds
- Click the Options menu in the same row as the secret and select Edit Secret.
- Record the contents of the Value field or fields. You can use this information to verify that the value is different after updating the credentials.
- Update the text in the Value field or fields with the new authentication information for your cloud provider, and then click Save.
If you are updating the credentials for a vSphere cluster that does not have the vSphere CSI Driver Operator enabled, you must force a rollout of the Kubernetes controller manager to apply the updated credentials.
NoteIf the vSphere CSI Driver Operator is enabled, this step is not required.
To apply the updated vSphere credentials, log in to the OpenShift Container Platform CLI as a user with the
cluster-admin
role and run the following command:$ oc patch kubecontrollermanager cluster \ -p='{"spec": {"forceRedeploymentReason": "recovery-'"$( date )"'"}}' \ --type=merge
While the credentials are rolling out, the status of the Kubernetes Controller Manager Operator reports
Progressing=true
. To view the status, run the following command:$ oc get co kube-controller-manager
If the CCO for your cluster is configured to use mint mode, delete each component secret that is referenced by the individual
CredentialsRequest
objects.-
Log in to the OpenShift Container Platform CLI as a user with the
cluster-admin
role. Get the names and namespaces of all referenced component secrets:
$ oc -n openshift-cloud-credential-operator get CredentialsRequest \ -o json | jq -r '.items[] | select (.spec.providerSpec.kind=="<provider_spec>") | .spec.secretRef'
where
<provider_spec>
is the corresponding value for your cloud provider:-
AWS:
AWSProviderSpec
-
GCP:
GCPProviderSpec
Partial example output for AWS
{ "name": "ebs-cloud-credentials", "namespace": "openshift-cluster-csi-drivers" } { "name": "cloud-credential-operator-iam-ro-creds", "namespace": "openshift-cloud-credential-operator" }
-
AWS:
Delete each of the referenced component secrets:
$ oc delete secret <secret_name> \1 -n <secret_namespace> 2
Example deletion of an AWS secret
$ oc delete secret ebs-cloud-credentials -n openshift-cluster-csi-drivers
You do not need to manually delete the credentials from your provider console. Deleting the referenced component secrets will cause the CCO to delete the existing credentials from the platform and create new ones.
-
Log in to the OpenShift Container Platform CLI as a user with the
Verification
To verify that the credentials have changed:
-
In the Administrator perspective of the web console, navigate to Workloads
Secrets. - Verify that the contents of the Value field or fields have changed.
Additional resources
6.14.3. Removing cloud provider credentials
After installing an OpenShift Container Platform cluster with the Cloud Credential Operator (CCO) in mint mode, you can remove the administrator-level credential secret from the kube-system
namespace in the cluster. The administrator-level credential is required only during changes that require its elevated permissions, such as upgrades.
Prior to a non z-stream upgrade, you must reinstate the credential secret with the administrator-level credential. If the credential is not present, the upgrade might be blocked.
Prerequisites
- Your cluster is installed on a platform that supports removing cloud credentials from the CCO. Supported platforms are AWS and GCP.
Procedure
-
In the Administrator perspective of the web console, navigate to Workloads
Secrets. In the table on the Secrets page, find the root secret for your cloud provider.
Platform Secret name AWS
aws-creds
GCP
gcp-credentials
- Click the Options menu in the same row as the secret and select Delete Secret.