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Creating a compute machine set on Azure Stack Hub

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

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 Azure Stack Hub

This sample YAML defines a compute machine set that runs in the 1 Microsoft Azure zone in a region 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:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> (1)
    machine.openshift.io/cluster-api-machine-role: <role> (2)
    machine.openshift.io/cluster-api-machine-type: <role> (2)
  name: <infrastructure_id>-<role>-<region> (3)
  namespace: openshift-machine-api
spec:
  replicas: 1
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id> (1)
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>-<region> (3)
  template:
    metadata:
      creationTimestamp: null
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id> (1)
        machine.openshift.io/cluster-api-machine-role: <role> (2)
        machine.openshift.io/cluster-api-machine-type: <role> (2)
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-<role>-<region> (3)
    spec:
      metadata:
        creationTimestamp: null
        labels:
          node-role.kubernetes.io/<role>: "" (2)
      providerSpec:
        value:
          apiVersion: machine.openshift.io/v1beta1
          availabilitySet: <availability_set> (6)
          credentialsSecret:
            name: azure-cloud-credentials
            namespace: openshift-machine-api
          image:
            offer: ""
            publisher: ""
            resourceID: /resourceGroups/<infrastructure_id>-rg/providers/Microsoft.Compute/images/<infrastructure_id> (1)
            sku: ""
            version: ""
          internalLoadBalancer: ""
          kind: AzureMachineProviderSpec
          location: <region> (4)
          managedIdentity: <infrastructure_id>-identity (1)
          metadata:
            creationTimestamp: null
          natRule: null
          networkResourceGroup: ""
          osDisk:
            diskSizeGB: 128
            managedDisk:
              storageAccountType: Premium_LRS
            osType: Linux
          publicIP: false
          publicLoadBalancer: ""
          resourceGroup: <infrastructure_id>-rg (1)
          sshPrivateKey: ""
          sshPublicKey: ""
          subnet: <infrastructure_id>-<role>-subnet  (1) (2)
          userDataSecret:
            name: worker-user-data (2)
          vmSize: Standard_DS4_v2
          vnet: <infrastructure_id>-vnet (1)
          zone: "1" (5)
1 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 installed, you can obtain the infrastructure ID by running the following command: 
$ oc get -o jsonpath='{.status.infrastructureName}{"\n"}' infrastructure cluster

You can obtain the subnet by running the following command:

$  oc -n openshift-machine-api \
    -o jsonpath='{.spec.template.spec.providerSpec.value.subnet}{"\n"}' \
    get machineset/<infrastructure_id>-worker-centralus1

You can obtain the vnet by running the following command:

$  oc -n openshift-machine-api \
    -o jsonpath='{.spec.template.spec.providerSpec.value.vnet}{"\n"}' \
    get machineset/<infrastructure_id>-worker-centralus1
2 Specify the node label to add.
3 Specify the infrastructure ID, node label, and region.
4 Specify the region to place machines on.
5 Specify the zone within your region to place machines on. Be sure that your region supports the zone that you specify.
6 Specify the availability set for the cluster.

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.

  • Create an availability set in which to deploy Azure Stack Hub compute machines.

Procedure

  1. 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 <availabilitySet>, <clusterID>, and <role> parameter values.

  2. 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.

    1. 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

    2. 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.

      For clusters that have user-provisioned infrastructure, a compute machine set can only create worker and infra 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.

  3. 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: nvidia-t4 (1)
    1 Specify 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.

    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

Enabling Azure boot diagnostics

You can enable boot diagnostics on Azure machines that your machine set creates.

Prerequisites

  • Have an existing Microsoft Azure Stack Hub cluster.

Procedure

  • Add the diagnostics configuration that is applicable to your storage type to the providerSpec field in your machine set YAML file:

    • For an Azure Managed storage account:

      providerSpec:
  diagnostics:
    boot:
      storageAccountType: AzureManaged (1)
      1 Specifies an Azure Managed storage account.

    • For an Azure Unmanaged storage account:

      providerSpec:
  diagnostics:
    boot:
      storageAccountType: CustomerManaged (1)
      customerManaged:
        storageAccountURI: https://<storage-account>.blob.core.windows.net (2)
      1 Specifies an Azure Unmanaged storage account.
      2 Replace <storage-account> with the name of your storage account.

      Only the Azure Blob Storage data service is supported.
Verification

  • On the Microsoft Azure portal, review the Boot diagnostics page for a machine deployed by the machine set, and verify that you can see the serial logs for the machine.

Enabling customer-managed encryption keys for a machine set

You can supply an encryption key to Azure to encrypt data on managed disks at rest. You can enable server-side encryption with customer-managed keys by using the Machine API.

An Azure Key Vault, a disk encryption set, and an encryption key are required to use a customer-managed key. The disk encryption set must be in a resource group where the Cloud Credential Operator (CCO) has granted permissions. If not, an additional reader role is required to be granted on the disk encryption set.

Prerequisites
Procedure

  • Configure the disk encryption set under the providerSpec field in your machine set YAML file. For example:

    providerSpec:
  value:
    osDisk:
      diskSizeGB: 128
      managedDisk:
        diskEncryptionSet:
          id: /subscriptions/<subscription_id>/resourceGroups/<resource_group_name>/providers/Microsoft.Compute/diskEncryptionSets/<disk_encryption_set_name>
        storageAccountType: Premium_LRS
Additional resources