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Control plane machine set configuration

This example YAML snippet shows the base structure for a control plane machine set custom resource (CR).

Sample YAML for a control plane machine set custom resource

The base of the ControlPlaneMachineSet CR is structured the same way for all platforms.

Sample ControlPlaneMachineSet CR YAML file
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. Specifies the name of the ControlPlaneMachineSet CR, which is cluster. Do not change this value.
  2. Specifies the number of control plane machines. Only clusters with three control plane machines are supported, so the replicas value is 3. Horizontal scaling is not supported. Do not change this value.
  3. Specifies 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
  4. Specifies 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 Operator, you must ensure that the ControlPlaneMachineSet CR configuration is correct for your cluster requirements. For more information about activating the Control Plane Machine Set Operator, see "Getting started with control plane machine sets".

  5. Specifies the update strategy for the cluster. The allowed values are OnDelete and RollingUpdate. The default value is RollingUpdate. For more information about update strategies, see "Updating the control plane configuration".
  6. Specifies the cloud provider platform name. Do not change this value.
  7. Specifies 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.
  8. Specifies 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.
Additional resources

Control plane machine set configuration options

You can configure your control plane machine set to customize your cluster to your needs.

Adding a custom prefix to control plane machine names

You can customize the prefix of machine names that the control plane machine set creates. This can be done by editing the ControlPlaneMachineSet custom resource (CR).

Procedure

  1. Edit the ControlPlaneMachineSet CR by running the following command:

    $ oc edit controlplanemachineset.machine.openshift.io cluster \
  -n openshift-machine-api

  2. Edit the .spec.machineNamePrefix field of the ControlPlaneMachineSet CR:

    apiVersion: machine.openshift.io/v1
kind: ControlPlaneMachineSet
metadata:
  name: cluster
  namespace: openshift-machine-api
spec:
  machineNamePrefix: <machine_prefix>
# ...

    where <machine_prefix> specifies a prefix name that follows the requirements for a lowercase RFC 1123 subdomain.

    Important

    A lowercase RFC 1123 subdomain must consist of only lowercase alphanumeric characters, hyphens ('-'), and periods ('.'). Each block, separated by periods, must start and end with an alphanumeric character. Hyphens are not allowed at the start or end of a block, and consecutive periods are not permitted.

  3. Save your changes.

Next steps

  • If you changed only the value of the machineNamePrefix parameter, clusters that use the default RollingUpdate update strategy are not automatically updated. To propagate this change, you must replace your control plane machines manually, regardless of the update strategy for the cluster. For more information, see "Replacing a control plane machine".

Additional resources

Provider-specific configuration options

The <platform_provider_spec> and <platform_failure_domains> sections of the control plane machine set manifests are provider specific. For provider-specific configuration options for your cluster, see the following resources: