Getting started with control plane machine sets

The process for getting started with control plane machine sets depends on the state of the ControlPlaneMachineSet custom resource (CR) in your cluster.

Clusters with an active generated CR

Clusters that have a generated CR with an active state use the control plane machine set by default. No administrator action is required.

Clusters with an inactive generated CR

For clusters that include an inactive generated CR, you must review the CR configuration and activate the CR.

Clusters without a generated CR

For clusters that do not include a generated CR, you must create and activate a CR with the appropriate configuration for your cluster.

If you are uncertain about the state of the ControlPlaneMachineSet CR in your cluster, you can verify the CR status.

Supported cloud providers

In OpenShift Container Platform 4.19, the control plane machine set is supported for Amazon Web Services (AWS), Google Cloud, Microsoft Azure, Nutanix, and VMware vSphere clusters.

The status of the control plane machine set after installation depends on your cloud provider and the version of OpenShift Container Platform that you installed on your cluster.

Table 1. Control plane machine set implementation for OpenShift Container Platform 4.19

Cloud provider	Active by default	Generated CR	Manual CR required
Amazon Web Services (AWS)	X [1]	X
Google Cloud	X [2]	X
Microsoft Azure	X [2]	X
Nutanix	X [3]	X
Red Hat OpenStack Platform (RHOSP)	X [3]	X
VMware vSphere	X [4]	X

1. AWS clusters that are upgraded from version 4.11 or earlier require CR activation.

2. Google Cloud and Azure clusters that are upgraded from version 4.12 or earlier require CR activation.

3. Nutanix and RHOSP clusters that are upgraded from version 4.13 or earlier require CR activation.

4. vSphere clusters that are upgraded from version 4.15 or earlier require CR activation.

Checking the control plane machine set custom resource state

You can verify the existence and state of the ControlPlaneMachineSet custom resource (CR).

Procedure

• Determine the state of the CR by running the following command:

  $ oc get controlplanemachineset.machine.openshift.io cluster \
    --namespace openshift-machine-api

  • A result of Active indicates that the ControlPlaneMachineSet CR exists and is activated. No administrator action is required.

  • A result of Inactive indicates that a ControlPlaneMachineSet CR exists but is not activated.

  • A result of NotFound indicates that there is no existing ControlPlaneMachineSet CR.

Next steps

To use the control plane machine set, you must ensure that a ControlPlaneMachineSet CR with the correct settings for your cluster exists.

• If your cluster has an existing CR, you must verify that the configuration in the CR is correct for your cluster.

• If your cluster does not have an existing CR, you must create one with the correct configuration for your cluster.

Activating the control plane machine set custom resource

To use the control plane machine set, you must ensure that a ControlPlaneMachineSet custom resource (CR) with the correct settings for your cluster exists. On a cluster with a generated CR, you must verify that the configuration in the CR is correct for your cluster and activate it.

Note

For more information about the parameters in the CR, see "Control plane machine set configuration".

Procedure

1. View the configuration of the CR by running the following command:

   $ oc --namespace openshift-machine-api edit controlplanemachineset.machine.openshift.io cluster

2. Change the values of any fields that are incorrect for your cluster configuration.

3. When the configuration is correct, activate the CR by setting the .spec.state field to Active and saving your changes.

   Important

   To activate the CR, you must change the .spec.state field to Active in the same oc edit session that you use to update the CR configuration. If the CR is saved with the state left as Inactive, the control plane machine set generator resets the CR to its original settings.

Additional resources

• Control plane machine set configuration

Creating a control plane machine set custom resource

To use the control plane machine set, you must ensure that a ControlPlaneMachineSet custom resource (CR) with the correct settings for your cluster exists. On a cluster without a generated CR, you must create the CR manually and activate it.

Note

For more information about the structure and parameters of the CR, see "Control plane machine set configuration".

Procedure

1. Create a YAML file using the following template:

   Control plane machine set CR YAML file template

   apiVersion: machine.openshift.io/v1
   kind: ControlPlaneMachineSet
   metadata:
     name: cluster
     namespace: openshift-machine-api
   spec:
     replicas: 3
     selector:
       matchLabels:
         machine.openshift.io/cluster-api-cluster: <cluster_id> 
         machine.openshift.io/cluster-api-machine-role: master
         machine.openshift.io/cluster-api-machine-type: master
     state: Active 
     strategy:
       type: RollingUpdate 
     template:
       machineType: machines_v1beta1_machine_openshift_io
       machines_v1beta1_machine_openshift_io:
         failureDomains:
           platform: <platform> 
           <platform_failure_domains> 
         metadata:
           labels:
             machine.openshift.io/cluster-api-cluster: <cluster_id> 
             machine.openshift.io/cluster-api-machine-role: master
             machine.openshift.io/cluster-api-machine-type: master
         spec:
           providerSpec:
             value:
               <platform_provider_spec> 

   1. Specify the infrastructure ID that is based on the cluster ID that you set when you provisioned the cluster. You must specify this value when you create a ControlPlaneMachineSet CR. If you have the OpenShift CLI (oc) installed, you can obtain the infrastructure ID by running the following command:

      $ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster

   2. Specify the state of the Operator. When the state is Inactive, the Operator is not operational. You can activate the Operator by setting the value to Active.

      Important

      Before you activate the CR, you must ensure that its configuration is correct for your cluster requirements.

   3. Specify the update strategy for the cluster. Valid values are OnDelete and RollingUpdate. The default value is RollingUpdate. For more information about update strategies, see "Updating the control plane configuration".
   4. Specify your cloud provider platform name. Valid values are AWS, Azure, GCP, Nutanix, VSphere, and OpenStack.
   5. Add the <platform_failure_domains> configuration for the cluster. The format and values of this section are provider-specific. For more information, see the sample failure domain configuration for your cloud provider.
   6. Specify the infrastructure ID.
   7. Add the <platform_provider_spec> configuration for the cluster. The format and values of this section are provider-specific. For more information, see the sample provider specification for your cloud provider.

2. Refer to the sample YAML for a control plane machine set CR and populate your file with values that are appropriate for your cluster configuration.

3. Refer to the sample failure domain configuration and sample provider specification for your cloud provider and update those sections of your file with the appropriate values.

4. When the configuration is correct, activate the CR by setting the .spec.state field to Active and saving your changes.

5. Create the CR from your YAML file by running the following command:

   $ oc create -f <control_plane_machine_set>.yaml

   where <control_plane_machine_set> is the name of the YAML file that contains the CR configuration.

Additional resources

• Updating the control plane configuration

• Control plane machine set configuration

• Provider-specific configuration options