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Configuring multi-architecture compute machines on an OKD cluster

An OKD cluster with multi-architecture compute machines is a cluster that supports compute machines with different architectures. You can deploy a cluster with multi-architecture compute machines by creating an Azure installer-provisioned cluster using the multi-architecture installer binary. For Azure installation, see Installing a cluster on Azure with customizations.

The multi-architecture compute machines Technology Preview feature has limited usability with installing, upgrading, and running payloads.

The following procedures explain how to generate an ARM64 boot image and create an Azure compute machine set with the ARM64 boot image. This adds ARM64 compute nodes to your cluster and deploys the desired amount of ARM64 virtual machines (VM). This section also shows how to upgrade your existing cluster to a cluster that supports multi-architecture compute machines. Clusters with multi-architecture compute machines are only available on Azure installer-provisioned infrastructures with x86_64 control plane machines.

OKD clusters with multi-architecture compute machines on Azure installer-provisioned infrastructure installations is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

Creating an ARM64 boot image using the Azure image gallery

To configure your cluster with multi-architecture compute machines, you must create an ARM64 boot image and add it to your Azure compute machine set. The following procedure describes how to manually generate an ARM64 boot image.

Prerequisites

  • You installed the Azure CLI (az).

  • You created a single-architecture Azure installer-provisioned cluster with the multi-architecture installer binary.

Procedure

  1. Log in to your Azure account:

    $ az login

  2. Create a storage account and upload the ARM64 virtual hard disk (VHD) to your storage account. The OKD installation program creates a resource group, however, the boot image can also be uploaded to a custom named resource group:

    $ az storage account create -n ${STORAGE_ACCOUNT_NAME} -g ${RESOURCE_GROUP} -l westus --sku Standard_LRS (1)
    1 The westus object is an example region.

  3. Create a storage container using the storage account you generated:

    $ az storage container create -n ${CONTAINER_NAME} --account-name ${STORAGE_ACCOUNT_NAME}

  4. You must use the OKD installation program JSON file to extract the URL and aarch64 VHD name:

    1. Extract the URL field and set it to RHCOS_VHD_ORIGIN_URL as the file name by running the following command:

      $ RHCOS_VHD_ORIGIN_URL=$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.aarch64."rhel-coreos-extensions"."azure-disk".url')

    2. Extract the aarch64 VHD name and set it to BLOB_NAME as the file name by running the following command:

      $ BLOB_NAME=rhcos-$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.aarch64."rhel-coreos-extensions"."azure-disk".release')-azure.aarch64.vhd

  5. Generate a shared access signature (SAS) token. Use this token to upload the FCOS VHD to your storage container with the following commands:

    $ end=`date -u -d "30 minutes" '+%Y-%m-%dT%H:%MZ'`
    $ sas=`az storage container generate-sas -n ${CONTAINER_NAME} --account-name ${STORAGE_ACCOUNT_NAME} --https-only --permissions dlrw --expiry $end -o tsv`

  6. Copy the FCOS VHD into the storage container:

    $ az storage blob copy start --account-name ${STORAGE_ACCOUNT_NAME} --sas-token "$sas" \
 --source-uri "${RHCOS_VHD_ORIGIN_URL}" \
 --destination-blob "${BLOB_NAME}" --destination-container ${CONTAINER_NAME}

    You can check the status of the copying process with the following command:

    $ az storage blob show -c ${CONTAINER_NAME} -n ${BLOB_NAME} --account-name ${STORAGE_ACCOUNT_NAME} | jq .properties.copy
    Example output
    {
 "completionTime": null,
 "destinationSnapshot": null,
 "id": "1fd97630-03ca-489a-8c4e-cfe839c9627d",
 "incrementalCopy": null,
 "progress": "17179869696/17179869696",
 "source": "https://rhcos.blob.core.windows.net/imagebucket/rhcos-411.86.202207130959-0-azure.aarch64.vhd",
 "status": "success", (1)
 "statusDescription": null
}
    1 If the status parameter displays the success object, the copying process is complete.

  7. Create an image gallery using the following command:

    $ az sig create --resource-group ${RESOURCE_GROUP} --gallery-name ${GALLERY_NAME}

    Use the image gallery to create an image definition. In the following example command, rhcos-arm64 is the name of the image definition.

    $ az sig image-definition create --resource-group ${RESOURCE_GROUP} --gallery-name ${GALLERY_NAME} --gallery-image-definition rhcos-arm64 --publisher RedHat --offer arm --sku arm64 --os-type linux --architecture Arm64 --hyper-v-generation V2

  8. To get the URL of the VHD and set it to RHCOS_VHD_URL as the file name, run the following command:

    $ RHCOS_VHD_URL=$(az storage blob url --account-name ${STORAGE_ACCOUNT_NAME} -c ${CONTAINER_NAME} -n "${BLOB_NAME}" -o tsv)

  9. Use the RHCOS_VHD_URL file, your storage account, resource group, and image gallery to create an image version. In the following example, 1.0.0 is the image version.

    $ az sig image-version create --resource-group ${RESOURCE_GROUP} --gallery-name ${GALLERY_NAME} --gallery-image-definition rhcos-arm64 --gallery-image-version 1.0.0 --os-vhd-storage-account ${STORAGE_ACCOUNT_NAME} --os-vhd-uri ${RHCOS_VHD_URL}

  10. Your ARM64 boot image is now generated. You can access the ID of your image with the following command:

    $ az sig image-version show -r $GALLERY_NAME -g $RESOURCE_GROUP -i rhcos-arm64 -e 1.0.0

    The following example image ID is used in the recourseID parameter of the machine set:

    Example resourceID
    /resourceGroups/${RESOURCE_GROUP}/providers/Microsoft.Compute/galleries/${GALLERY_NAME}/images/rhcos-arm64/versions/1.0.0

Adding a multi-architecture compute machine set to your cluster using the ARM64 boot image

To add ARM64 compute nodes to your cluster, you must create an Azure compute machine set that uses the ARM64 boot image. To create your own custom compute machine set on Azure, see "Creating a compute machine set on Azure".

Prerequisites

  • You installed the OpenShift CLI (oc).

Procedure

  • Create a machine set and modify the resourceID and vmSize parameters with the following command. This machine set will control the ARM64 worker nodes in your cluster:

    $ oc create -f arm64-machine-set-0.yaml
    Sample YAML machine set with ARM64 boot image
    apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id>
    machine.openshift.io/cluster-api-machine-role: worker
    machine.openshift.io/cluster-api-machine-type: worker
  name: <infrastructure_id>-arm64-machine-set-0
  namespace: openshift-machine-api
spec:
  replicas: 2
  selector:
    matchLabels:
      machine.openshift.io/cluster-api-cluster: <infrastructure_id>
      machine.openshift.io/cluster-api-machineset: <infrastructure_id>-arm64-machine-set-0
  template:
    metadata:
      labels:
        machine.openshift.io/cluster-api-cluster: <infrastructure_id>
        machine.openshift.io/cluster-api-machine-role: worker
        machine.openshift.io/cluster-api-machine-type: worker
        machine.openshift.io/cluster-api-machineset: <infrastructure_id>-arm64-machine-set-0
    spec:
      lifecycleHooks: {}
      metadata: {}
      providerSpec:
        value:
          acceleratedNetworking: true
          apiVersion: machine.openshift.io/v1beta1
          credentialsSecret:
            name: azure-cloud-credentials
            namespace: openshift-machine-api
          image:
            offer: ""
            publisher: ""
            resourceID: /resourceGroups/${RESOURCE_GROUP}/providers/Microsoft.Compute/galleries/${GALLERY_NAME}/images/rhcos-arm64/versions/1.0.0 (1)
            sku: ""
            version: ""
          kind: AzureMachineProviderSpec
          location: <region>
          managedIdentity: <infrastructure_id>-identity
          networkResourceGroup: <infrastructure_id>-rg
          osDisk:
            diskSettings: {}
            diskSizeGB: 128
            managedDisk:
              storageAccountType: Premium_LRS
            osType: Linux
          publicIP: false
          publicLoadBalancer: <infrastructure_id>
          resourceGroup: <infrastructure_id>-rg
          subnet: <infrastructure_id>-worker-subnet
          userDataSecret:
            name: worker-user-data
          vmSize: Standard_D4ps_v5 (2)
          vnet: <infrastructure_id>-vnet
          zone: "<zone>"
    1 Set the resourceID parameter to the arm64 boot image.
    2 Set the vmSize parameter to the instance type used in your installation. Some example instance types are Standard_D4ps_v5 or D8ps.
Verification

  1. Verify that the new ARM64 machines are running by entering the following command:

    $ oc get machineset -n openshift-machine-api
    Example output
    NAME                                                DESIRED  CURRENT  READY  AVAILABLE  AGE
<infrastructure_id>-arm64-machine-set-0                   2        2      2          2  10m

  2. You can check that the nodes are ready and scheduable with the following command:

    $ oc get nodes
Additional resources

Upgrading a cluster with multi-architecture compute machines

You must perform an explicit upgrade command to upgrade your existing cluster to a cluster that supports multi-architecture compute machines.

Prerequisites

  • You installed the OpenShift CLI (oc).

Procedure

  • To manually upgrade your cluster, use the following command:

    $ oc adm upgrade --allow-explicit-upgrade --to-image <image-pullspec> (1)
    1 You can access the image-pullspec object from the mixed-arch mirrors page in the release.txt file.