Creating a compute machine set on bare metal

You can create a different compute machine set to serve a specific purpose in your OpenShift Container Platform cluster on bare metal. For example, you might create infrastructure machine sets and related machines so that you can move supporting workloads to the new machines.

Important

You can use the advanced machine management and scaling capabilities only in clusters where the Machine API is operational. Clusters with user-provisioned infrastructure require additional validation and configuration to use the Machine API.

Clusters with the infrastructure platform type none cannot use the Machine API. This limitation applies even if the compute machines that are attached to the cluster are installed on a platform that supports the feature. This parameter cannot be changed after installation.

To view the platform type for your cluster, run the following command:

$ oc get infrastructure cluster -o jsonpath='{.status.platform}'

Sample YAML for a compute machine set custom resource on bare metal

This sample YAML defines a compute machine set that runs on bare metal and creates nodes that are labeled with node-role.kubernetes.io/<role>: "".

In this sample, <infrastructure_id> is the infrastructure ID label that is based on the cluster ID that you set when you provisioned the cluster, and <role> is the node label to add.

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  creationTimestamp: null
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 
  name: <infrastructure_id>-<role> 
  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:
      creationTimestamp: null
      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:
      metadata:
        creationTimestamp: null
        labels:
          node-role.kubernetes.io/<role>: "" 
      providerSpec:
        value:
          apiVersion: baremetal.cluster.k8s.io/v1alpha1
          hostSelector: {}
          image:
            checksum: http:/172.22.0.3:6181/images/rhcos-<version>.<architecture>.qcow2.<md5sum> 
            url: http://172.22.0.3:6181/images/rhcos-<version>.<architecture>.qcow2 
          kind: BareMetalMachineProviderSpec
          metadata:
            creationTimestamp: null
          userData:
            name: worker-user-data-managed

Specify the infrastructure ID that is based on the cluster ID that you set when you provisioned the cluster. 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 infrastructure ID and node label.
Specify the node label to add.
Edit the checksum URL to use the API VIP address.
Edit the url URL to use the API VIP address.

Creating a compute machine set

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

Prerequisites

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

Procedure

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> 
  name: <infrastructure_id>-<role> 
  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: 
        ...

The cluster infrastructure ID.
A default node label.
Note

For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra type machines.
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 and CURRENT values match. If the compute machine set is not available, wait a few minutes and run the command again.

Labeling GPU machine sets for the cluster autoscaler

You can use a machine set label to indicate which machines the cluster autoscaler can use to deploy GPU-enabled nodes.

Prerequisites

Your cluster uses a cluster autoscaler.

Procedure

On the machine set that you want to create machines for the cluster autoscaler to use to deploy GPU-enabled nodes, add a cluster-api/accelerator label:
apiVersion: machine.openshift.io/v1beta1 kind: MachineSet metadata: name: machine-set-name spec: template: spec: metadata: labels: cluster-api/accelerator: <accelerator_name>
where:

<accelerator_name>

Specifies a label of your choice that consists of alphanumeric characters, -, _, or . and starts and ends with an alphanumeric character. For example, you might use nvidia-t4 to represent Nvidia T4 GPUs, or nvidia-a10g for A10G GPUs.

Note

You must specify the value of this label for the spec.resourceLimits.gpus.type parameter in your ClusterAutoscaler CR. For more information, see "Cluster autoscaler resource definition".

Additional resources

Cluster autoscaler resource definition