Getting started with control plane machine sets

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 OKD 4, the control plane machine set is supported for Amazon Web Services (AWS), Google Cloud Platform (GCP), 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 OKD that you installed on your cluster.

Table 1. Control plane machine set implementation for OKD 4
Cloud provider	Active by default	Generated CR	Manual CR required
Amazon Web Services (AWS)	X ^[1]	X
Google Cloud Platform (GCP)	X ^[2]	X
Microsoft Azure	X ^[2]	X
Nutanix	X ^[3]	X
VMware vSphere			X
OpenStack	X ^[3]	X

AWS clusters that are upgraded from version 4.11 or earlier require CR activation.
GCP and Azure clusters that are upgraded from version 4.12 or earlier require CR activation.
Nutanix and OpenStack clusters that are upgraded from version 4.13 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.

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

Procedure

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

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

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

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

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.

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

Procedure

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> (1)
      machine.openshift.io/cluster-api-machine-role: master
      machine.openshift.io/cluster-api-machine-type: master
  state: Active (2)
  strategy:
    type: RollingUpdate (3)
  template:
    machineType: machines_v1beta1_machine_openshift_io
    machines_v1beta1_machine_openshift_io:
      failureDomains:
        platform: <platform> (4)
        <platform_failure_domains> (5)
      metadata:
        labels:
          machine.openshift.io/cluster-api-cluster: <cluster_id> (6)
          machine.openshift.io/cluster-api-machine-role: master
          machine.openshift.io/cluster-api-machine-type: master
      spec:
        providerSpec:
          value:
            <platform_provider_spec> (7)

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

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.

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.

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.

VMware vSphere does not support failure domains. For vSphere clusters, replace <platform_failure_domains> with an empty failureDomains: parameter.

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.

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