Chapter 4. Configuring multi-architecture compute machines on an OpenShift Container Platform cluster
An OpenShift Container Platform 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.
OpenShift Container Platform 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.
4.1. 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
Log in to your Azure account:
$ az login
Create a storage account and upload the ARM64 virtual hard disk (VHD) to your storage account. The OpenShift Container Platform 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.
Create a storage container using the storage account you generated:
$ az storage container create -n ${CONTAINER_NAME} --account-name ${STORAGE_ACCOUNT_NAME}
You must use the OpenShift Container Platform installation program JSON file to extract the URL and
aarch64
VHD name:Extract the
URL
field and set it toRHCOS_VHD_ORIGIN_URL
as the file name by running the following command:$ RHCOS_VHD_ORIGIN_URL=$(oc -n openshift-machine-config-operator get configmap/coreos-bootimages -o jsonpath='{.data.stream}' | jq -r '.architectures.aarch64."rhel-coreos-extensions"."azure-disk".url')
Extract the
aarch64
VHD name and set it toBLOB_NAME
as the file name by running the following command:$ 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
Generate a shared access signature (SAS) token. Use this token to upload the RHCOS 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`
Copy the RHCOS 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.
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 ${GALLERY_NAME} --gallery-image-definition rhcos-arm64 --publisher RedHat --offer arm --sku arm64 --os-type linux --architecture Arm64 --hyper-v-generation V2
To get the URL of the VHD and set it to
RHCOS_VHD_URL
as the file name, run the following command:$ RHCOS_VHD_URL=$(az storage blob url --account-name ${STORAGE_ACCOUNT_NAME} -c ${CONTAINER_NAME} -n "${BLOB_NAME}" -o tsv)
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}
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/${GALLERY_NAME}/images/rhcos-arm64/versions/1.0.0
4.2. Adding a multi-architecture compute machine set to your cluster using the ARM64 boot image
To add ARM64 compute nodes to your cluster, you must create an Azure compute machine set that uses the ARM64 boot image. To create your own custom compute machine set on Azure, see "Creating a compute machine set on Azure".
Prerequisites
-
You installed the OpenShift CLI (
oc
).
Procedure
Create a machine set and modify the
resourceID
andvmSize
parameters with the following command. This machine set will control the ARM64 worker nodes in your cluster:$ 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>"
Verification
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
You can check that the nodes are ready and scheduable with the following command:
$ oc get nodes
Additional resources
4.3. 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