Creating a cluster with multi-architecture compute machines on AWS

To create an AWS cluster with multi-architecture compute machines, you must first create a single-architecture AWS installer-provisioned cluster with the multi-architecture installer binary. For more information on AWS installations, see Installing a cluster on AWS with customizations.

You can also migrate your current cluster with single-architecture compute machines to a cluster with multi-architecture compute machines. For more information, see Migrating to a cluster with multi-architecture compute machines.

After creating a multi-architecture cluster, you can add nodes with different architectures to the cluster.

Verifying cluster compatibility

Before you can start adding compute nodes of different architectures to your cluster, you must verify that your cluster is multi-architecture compatible.

Prerequisites

You installed the OpenShift CLI (oc).

Procedure

Log in to the OpenShift CLI (oc).
You can check that your cluster uses the architecture payload by running the following command:
```
$ oc adm release info -o jsonpath="{ .metadata.metadata}"
```

Verification

If you see the following output, your cluster is using the multi-architecture payload:
```
{
 "release.openshift.io/architecture": "multi",
 "url": "https://access.redhat.com/errata/<errata_version>"
}
```
You can then begin adding multi-arch compute nodes to your cluster.
If you see the following output, your cluster is not using the multi-architecture payload:
```
{
 "url": "https://access.redhat.com/errata/<errata_version>"
}
```
Important

To migrate your cluster so the cluster supports multi-architecture compute machines, follow the procedure in Migrating to a cluster with multi-architecture compute machines.

Adding a multi-architecture compute machine set to your AWS cluster

After creating a multi-architecture cluster, you can add nodes with different architectures.

You can add multi-architecture compute machines to a multi-architecture cluster in the following ways:

Adding 64-bit x86 compute machines to a cluster that uses 64-bit ARM control plane machines and already includes 64-bit ARM compute machines. In this case, 64-bit x86 is considered the secondary architecture.
Adding 64-bit ARM compute machines to a cluster that uses 64-bit x86 control plane machines and already includes 64-bit x86 compute machines. In this case, 64-bit ARM is considered the secondary architecture.

Note

Before adding a secondary architecture node to your cluster, it is recommended to install the Multiarch Tuning Operator, and deploy a ClusterPodPlacementConfig custom resource. For more information, see "Managing workloads on multi-architecture clusters by using the Multiarch Tuning Operator".

Prerequisites

You installed the OpenShift CLI (oc).
You used the installation program to create an 64-bit ARM or 64-bit x86 single-architecture AWS cluster with the multi-architecture installer binary.

Procedure

Log in to the OpenShift CLI (oc).

Create a YAML file, and add the configuration to create a compute machine set to control the 64-bit ARM or 64-bit x86 compute nodes in your cluster.

Example MachineSet object for an AWS 64-bit ARM or x86 compute node

apiVersion: machine.openshift.io/v1beta1
kind: MachineSet
metadata:
  labels:
    machine.openshift.io/cluster-api-cluster: <infrastructure_id> 
  name: <infrastructure_id>-aws-machine-set-0 
  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>-<zone> 
  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>-<zone> 
    spec:
      metadata:
        labels:
          node-role.kubernetes.io/<role>: ""
      providerSpec:
        value:
          ami:
            id: ami-02a574449d4f4d280 
          apiVersion: awsproviderconfig.openshift.io/v1beta1
          blockDevices:
            - ebs:
                iops: 0
                volumeSize: 120
                volumeType: gp2
          credentialsSecret:
            name: aws-cloud-credentials
          deviceIndex: 0
          iamInstanceProfile:
            id: <infrastructure_id>-worker-profile 
          instanceType: m6g.xlarge 
          kind: AWSMachineProviderConfig
          placement:
            availabilityZone: us-east-1a 
            region: <region> 
          securityGroups:
            - filters:
                - name: tag:Name
                  values:
                    - <infrastructure_id>-node 
          subnet:
            filters:
              - name: tag:Name
                values:
                  - <infrastructure_id>-subnet-private-<zone>
          tags:
            - name: kubernetes.io/cluster/<infrastructure_id> 
              value: owned
            - name: <custom_tag_name>
              value: <custom_tag_value>
          userDataSecret:
            name: worker-user-data

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, role node label, and zone.
Specify the role node label to add.

Specify a Red Hat Enterprise Linux CoreOS (RHCOS) Amazon Machine Image (AMI) for your AWS region for the nodes. The RHCOS AMI must be compatible with the machine architecture.

$ oc get configmap/coreos-bootimages \
	  -n openshift-machine-config-operator \
	  -o jsonpath='{.data.stream}' | jq \
	  -r '.architectures.<arch>.images.aws.regions."<region>".image'

Specify a machine type that aligns with the CPU architecture of the chosen AMI. For more information, see "Tested instance types for AWS 64-bit ARM"
Specify the zone. For example, us-east-1a. Ensure that the zone you select has machines with the required architecture.
Specify the region. For example, us-east-1. Ensure that the zone you select has machines with the required architecture.

Create the compute machine set by running the following command:
```
$ oc create -f <file_name> 
```
1. Replace <file_name> with the name of the YAML file with compute machine set configuration. For example: aws-arm64-machine-set-0.yaml, or aws-amd64-machine-set-0.yaml.

Verification

View the list of compute machine sets by running the following command:

$ oc get machineset -n openshift-machine-api

The output must include the machine set that you created.

Example output

NAME                                                DESIRED  CURRENT  READY  AVAILABLE  AGE
<infrastructure_id>-aws-machine-set-0                   2        2      2          2  10m

You can check if the nodes are ready and schedulable by running the following command:
```
$ oc get nodes
```

Additional resources