Deploying hosted control planes on IBM Power - Deploying hosted control planes | Hosted control planes

Prerequisites to configure hosted control planes on IBM Power
IBM Power infrastructure requirements
DNS configuration for hosted control planes on IBM Power
- Defining a custom DNS name
Creating a hosted cluster on bare metal
- Creating a hosted cluster by using the CLI
Creating heterogeneous node pools on agent hosted clusters

You can deploy hosted control planes by configuring a cluster to function as a hosting cluster. The hosting cluster is an OKD cluster where the control planes are hosted. The hosting cluster is also known as the management cluster.

The management cluster is not the managed cluster. A managed cluster is a cluster that the hub cluster manages.

The multicluster engine Operator supports only the default local-cluster, which is a hub cluster that is managed, and the hub cluster as the hosting cluster.

To provision hosted control planes on bare metal, you can use the Agent platform. The Agent platform uses the central infrastructure management service to add worker nodes to a hosted cluster. For more information, see "Enabling the central infrastructure management service".

Each IBM Power host must be started with a Discovery Image that the central infrastructure management provides. After each host starts, it runs an Agent process to discover the details of the host and completes the installation. An Agent custom resource represents each host.

When you create a hosted cluster with the Agent platform, HyperShift installs the Agent Cluster API provider in the hosted control plane namespace.

Prerequisites to configure hosted control planes on IBM Power

The multicluster engine for Kubernetes Operator version 2.7 and later installed on an OKD cluster. The multicluster engine Operator is automatically installed when you install Red Hat Advanced Cluster Management (RHACM). You can also install the multicluster engine Operator without RHACM as an Operator from the OKD OperatorHub.
The multicluster engine Operator must have at least one managed OKD cluster. The local-cluster managed hub cluster is automatically imported in the multicluster engine Operator version 2.7 and later. For more information about local-cluster, see Advanced configuration in the RHACM documentation. You can check the status of your hub cluster by running the following command:
```
$ oc get managedclusters local-cluster
```
You need a hosting cluster with at least 3 worker nodes to run the HyperShift Operator.
You need to enable the central infrastructure management service. For more information, see "Enabling the central infrastructure management service".
You need to install the hosted control plane command-line interface. For more information, see "Installing the hosted control plane command-line interface".

The hosted control planes feature is enabled by default. If you disabled the feature and want to manually enable it, see "Manually enabling the hosted control planes feature". If you need to disable the feature, see "Disabling the hosted control planes feature".

Additional resources

IBM Power infrastructure requirements

The Agent platform does not create any infrastructure, but requires the following resources for infrastructure:

Agents: An Agent represents a host that is booted with a discovery image and is ready to be provisioned as an OKD node.
DNS: The API and Ingress endpoints must be routable.

DNS configuration for hosted control planes on IBM Power

The API server for the hosted cluster is exposed. A DNS entry must exist for the api.<hosted_cluster_name>.<basedomain> entry that points to the destination where the API server is reachable.

The DNS entry can be as simple as a record that points to one of the nodes in the managed cluster that is running the hosted control plane.

The entry can also point to a load balancer that is deployed to redirect incoming traffic to the ingress pods.

See the following example of a DNS configuration:

$ cat /var/named/<example.krnl.es.zone>

Example output

$ TTL 900
@ IN  SOA bastion.example.krnl.es.com. hostmaster.example.krnl.es.com. (
      2019062002
      1D 1H 1W 3H )
  IN NS bastion.example.krnl.es.com.
;
;
api                   IN A 1xx.2x.2xx.1xx (1)
api-int               IN A 1xx.2x.2xx.1xx
;
;
*.apps.<hosted-cluster-name>.<basedomain>           IN A 1xx.2x.2xx.1xx
;
;EOF

1	The record refers to the IP address of the API load balancer that handles ingress and egress traffic for hosted control planes.

For IBM Power, add IP addresses that correspond to the IP address of the agent.

Example configuration

compute-0              IN A 1xx.2x.2xx.1yy
compute-1              IN A 1xx.2x.2xx.1yy

Defining a custom DNS name

As a cluster administrator, you can create a hosted cluster with an external API DNS name that is different from the internal endpoint that is used for node bootstraps and control plane communication. You might want to define a different DNS name for the following reasons:

To replace the user-facing TLS certificate with one from a public CA without breaking the control plane functions that are bound to the internal root CA
To support split-horizon DNS and NAT scenarios
To ensure a similar experience to standalone control planes, where you can use functions, such as the "Show Login Command" function, with the correct kubeconfig and DNS configuration

You can define a DNS name either during your initial setup or during day-2 operations, by entering a domain name in the kubeAPIServerDNSName field of a HostedCluster object.

Prerequisites

You have a valid TLS certificate that covers the DNS name that you will set in the kubeAPIServerDNSName field.
Your DNS name is a resolvable URI that is reachable and pointing to the right address.

Procedure

In the specification for the HostedCluster object, add the kubeAPIServerDNSName field and the address for the domain and specify which certificate to use, as shown in the following example:

#...
spec:
  configuration:
    apiServer:
      servingCerts:
        namedCertificates:
        - names:
          - xxx.example.com
          - yyy.example.com
          servingCertificate:
            name: <my_serving_certificate>
  kubeAPIServerDNSName: <your_custom_address> (1)

1	The value for the `kubeAPIServerDNSName` field must be a valid, addressable domain.

After you define the kubeAPIServerDNSName field and specify the certificate, the Control Plane Operator controllers create a kubeconfig file named custom-admin-kubeconfig, which is stored in the HostedControlPlane namespace. The certificates are generated from the root CA, and the HostedControlPlane namespace manages their expiration and renewal.

The Control Plane Operator reports a new kubeconfig file named CustomKubeconfig in the HostedControlPlane namespace. That file uses the new server that is defined in the kubeAPIServerDNSName field.

The custom kubeconfig file is referenced in the HostedCluster object in the status field as CustomKubeconfig. The CustomKubeConfig field is optional, and can be added only if the kubeAPIServerDNSName field is not empty. When the CustomKubeConfig field is set, it triggers the generation of a secret named <hosted_cluster_name>-custom-admin-kubeconfig in the HostedCluster namespace. You can use the secret to access the HostedCluster API server. If you remove the CustomKubeConfig field during day-2 operations, all related secrets and status references are deleted.

This process does not directly affect the data plane, so no rollouts are expected to occur. The HostedControlPlane namespace receives the changes from the HyperShift Operator and deletes the corresponding fields.

If you remove the kubeAPIServerDNSName field from the specification for the HostedCluster object, all newly generated secrets and the CustomKubeconfig reference are removed from the cluster and from the status field.

Creating a hosted cluster on bare metal

You can create a hosted cluster or import one. When the Assisted Installer is enabled as an add-on to multicluster engine Operator and you create a hosted cluster with the Agent platform, the HyperShift Operator installs the Agent Cluster API provider in the hosted control plane namespace.

Creating a hosted cluster by using the CLI

To create a hosted cluster by using the command-line interface (CLI), complete the following steps.

Prerequisites

Each hosted cluster must have a cluster-wide unique name. A hosted cluster name cannot be the same as any existing managed cluster in order for the multicluster engine Operator to manage it.
Do not use clusters as a hosted cluster name.
A hosted cluster cannot be created in the namespace of a multicluster engine Operator managed cluster.
Verify that you have a default storage class configured for your cluster. Otherwise, you might see pending persistent volume claims (PVCs).
By default when you use the hcp create cluster agent command, the hosted cluster is created with node ports. However, the preferred publishing strategy for hosted clusters on bare metal is to expose services through a load balancer. If you create a hosted cluster by using the web console or by using Red Hat Advanced Cluster Management, to set a publishing strategy for a service besides the Kubernetes API server, you must manually specify the servicePublishingStrategy information in the HostedCluster custom resource. For more information, see step 4 in this procedure.
Ensure that you meet the requirements described in "Preparing to deploy hosted control planes on bare metal", which includes requirements related to infrastructure, firewalls, ports, and services. For example, those requirements describe how to add the appropriate zone labels to the bare-metal hosts in your management cluster, as shown in the following example commands:
```
$ oc label node [compute-node-1] topology.kubernetes.io/zone=zone1
```
```
$ oc label node [compute-node-2] topology.kubernetes.io/zone=zone2
```
```
$ oc label node [compute-node-3] topology.kubernetes.io/zone=zone3
```
Ensure that you have added bare-metal nodes to a hardware inventory.

Procedure

Create a namespace by entering the following command:
```
$ oc create ns <hosted_cluster_namespace>
```
Replace <hosted_cluster_namespace> with an identifier for your hosted cluster namespace. Typically, the namespace is created by the HyperShift Operator, but during the hosted cluster creation process on bare metal, a Cluster API provider role is generated that needs the namespace to already exist.

Create the configuration file for your hosted cluster by entering the following command:

$ hcp create cluster agent \
  --name=<hosted_cluster_name> \(1)
  --pull-secret=<path_to_pull_secret> \(2)
  --agent-namespace=<hosted_control_plane_namespace> \(3)
  --base-domain=<base_domain> \(4)
  --api-server-address=api.<hosted_cluster_name>.<base_domain> \(5)
  --etcd-storage-class=<etcd_storage_class> \(6)
  --ssh-key=<path_to_ssh_key> \(7)
  --namespace=<hosted_cluster_namespace> \(8)
  --control-plane-availability-policy=HighlyAvailable \(9)
  --release-image=quay.io/openshift-release-dev/ocp-release:<ocp_release_image>-multi \(10)
  --node-pool-replicas=<node_pool_replica_count> \(11)
  --render \
  --render-sensitive \
  --ssh-key <home_directory>/<path_to_ssh_key>/<ssh_key> > hosted-cluster-config.yaml (12)

1	Specify the name of your hosted cluster.
2	Specify the path to your pull secret, for example, `/user/name/pullsecret`.
3	Specify your hosted control plane namespace. To ensure that agents are available in this namespace, enter the `oc get agent -n <hosted_control_plane_namespace>` command.
4	Specify your base domain, for example, `krnl.es`.
5	The `--api-server-address` flag defines the IP address that is used for the Kubernetes API communication in the hosted cluster. If you do not set the `--api-server-address` flag, you must log in to connect to the management cluster.
6	Specify the etcd storage class name, for example, `lvm-storageclass`.
7	Specify the path to your SSH public key. The default file path is `~/.ssh/id_rsa.pub`.
8	Specify your hosted cluster namespace.
9	Specify the availability policy for the hosted control plane components. Supported options are `SingleReplica` and `HighlyAvailable`. The default value is `HighlyAvailable`.
10	Specify the supported OKD version that you want to use, for example, `4.19.0-multi`. If you are using a disconnected environment, replace `<ocp_release_image>` with the digest image. To extract the OKD release image digest, see "Extracting the release image digest".
11	Specify the node pool replica count, for example, `3`. You must specify the replica count as `0` or greater to create the same number of replicas. Otherwise, no node pools are created.
12	After the `--ssh-key` flag, specify the path to the SSH key; for example, `user/.ssh/id_rsa`.

Configure the service publishing strategy. By default, hosted clusters use the NodePort service publishing strategy because node ports are always available without additional infrastructure. However, you can configure the service publishing strategy to use a load balancer.
- If you are using the default NodePort strategy, configure the DNS to point to the hosted cluster compute nodes, not the management cluster nodes. For more information, see "DNS configurations on bare metal".
- For production environments, use the LoadBalancer strategy because it provides certificate handling and automatic DNS resolution. To change the service publishing strategy LoadBalancer, in your hosted cluster configuration file, edit the service publishing strategy details:
  ... spec: services: - service: APIServer servicePublishingStrategy: type: LoadBalancer (1) - service: Ignition servicePublishingStrategy: type: Route - service: Konnectivity servicePublishingStrategy: type: Route - service: OAuthServer servicePublishingStrategy: type: Route - service: OIDC servicePublishingStrategy: type: Route sshKey: name: <ssh_key> ...
  1 Specify LoadBalancer as the API Server type. For all other services, specify Route as the type.
Apply the changes to the hosted cluster configuration file by entering the following command:
```
$ oc apply -f hosted_cluster_config.yaml
```

Monitor the creation of the hosted cluster, node pools, and pods by entering the following commands:

$ oc get hostedcluster \
  <hosted_cluster_namespace> -n \
  <hosted_cluster_namespace> -o \
  jsonpath='{.status.conditions[?(@.status=="False")]}' | jq .

$ oc get nodepool \
  <hosted_cluster_namespace> -n \
  <hosted_cluster_namespace> -o \
  jsonpath='{.status.conditions[?(@.status=="False")]}' | jq .

$ oc get pods -n <hosted_cluster_namespace>

Confirm that the hosted cluster is ready. The cluster is ready when its status is Available: True, the node pool status shows AllMachinesReady: True, and all cluster Operators are healthy.

Install MetalLB in the hosted cluster:

Extract the kubeconfig file from the hosted cluster and set the environment variable for hosted cluster access by entering the following commands:

$ oc get secret \
  <hosted_cluster_namespace>-admin-kubeconfig \
  -n <hosted_cluster_namespace> \
  -o jsonpath='{.data.kubeconfig}' \
  | base64 -d > \
  kubeconfig-<hosted_cluster_namespace>.yaml

$ export KUBECONFIG="/path/to/kubeconfig-<hosted_cluster_namespace>.yaml"

Install the MetalLB Operator by creating the install-metallb-operator.yaml file:

apiVersion: v1
kind: Namespace
metadata:
  name: metallb-system
---
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: metallb-operator
  namespace: metallb-system
---
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: metallb-operator
  namespace: metallb-system
spec:
  channel: "stable"
  name: metallb-operator
  source: redhat-operators
  sourceNamespace: openshift-marketplace
  installPlanApproval: Automatic

Apply the file by entering the following command:
```
$ oc apply -f install-metallb-operator.yaml
```

Configure the MetalLB IP address pool by creating the deploy-metallb-ipaddresspool.yaml file:

apiVersion: metallb.io/v1beta1
kind: IPAddressPool
metadata:
  name: metallb
  namespace: metallb-system
spec:
  autoAssign: true
  addresses:
  - 10.11.176.71-10.11.176.75
---
apiVersion: metallb.io/v1beta1
kind: L2Advertisement
metadata:
  name: l2advertisement
  namespace: metallb-system
spec:
  ipAddressPools:
  - metallb

Apply the configuration by entering the following command:
```
$ oc apply -f deploy-metallb-ipaddresspool.yaml
```
Verify that MetalLB is installed by checking the Operator status, the IP address pool, and the L2Advertisement. Enter the following commands:
```
$ oc get pods -n metallb-system
```
```
$ oc get ipaddresspool -n metallb-system
```
```
$ oc get l2advertisement -n metallb-system
```

Configure the load balancer for ingress:

Create the ingress-loadbalancer.yaml file:

apiVersion: v1
kind: Service
metadata:
  annotations:
    metallb.universe.tf/address-pool: metallb
  name: metallb-ingress
  namespace: openshift-ingress
spec:
  ports:
    - name: http
      protocol: TCP
      port: 80
      targetPort: 80
    - name: https
      protocol: TCP
      port: 443
      targetPort: 443
  selector:
    ingresscontroller.operator.openshift.io/deployment-ingresscontroller: default
  type: LoadBalancer

Apply the configuration by entering the following command:
```
$ oc apply -f ingress-loadbalancer.yaml
```

Verify that the load balancer service works as expected by entering the following command:

$ oc get svc metallb-ingress -n openshift-ingress

Example output

NAME              TYPE           CLUSTER-IP       EXTERNAL-IP    PORT(S)                      AGE
metallb-ingress   LoadBalancer   172.31.127.129   10.11.176.71   80:30961/TCP,443:32090/TCP   16h

Configure the DNS to work with the load balancer:
1. Configure the DNS for the apps domain by pointing the *.apps.<hosted_cluster_namespace>.<base_domain> wildcard DNS record to the load balancer IP address.
2. Verify the DNS resolution by entering the following command:
  $ nslookup console-openshift-console.apps.<hosted_cluster_namespace>.<base_domain> <load_balancer_ip_address>
  Example output
  Server: 10.11.176.1 Address: 10.11.176.1#53 Name: console-openshift-console.apps.my-hosted-cluster.sample-base-domain.com Address: 10.11.176.71

Verification

Check the cluster Operators by entering the following command:
```
$ oc get clusteroperators
```
Ensure that all Operators show AVAILABLE: True, PROGRESSING: False, and DEGRADED: False.
Check the nodes by entering the following command:
```
$ oc get nodes
```
Ensure that the status of all nodes is READY.

Test access to the console by entering the following URL in a web browser:

https://console-openshift-console.apps.<hosted_cluster_namespace>.<base_domain>

Additional resources

Creating heterogeneous node pools on agent hosted clusters

On the agent platform, you can create heterogeneous node pools so that your clusters can run diverse machine types, such as x86_64 or ppc64le, within a single hosted cluster.

About creating heterogeneous node pools on agent hosted clusters

A node pool is a group of nodes within a cluster that share the same configuration. Heterogeneous node pools are pools that have different configurations, allowing you to create pools optimized for various workloads.

You can create heterogeneous node pools on the agent platform. It enables clusters to run diverse machine types, for example, x86_64 or ppc64le, within a single hosted cluster.

To create a heterogeneous node pool, perform the following general steps, as described in the following sections:

Create an AgentServiceConfig custom resource (CR) that informs the Operator how much storage is needed for components such as the database and filesystem. The CR also defines which OKD versions to maintain.
Create an agent cluster.
Create the heterogeneous node pool.
Configure DNS for hosted control planes
Create an InfraEnv custom resource (CR) for each architecture.
Add agents to the heterogeneous cluster.

Creating the AgentServiceConfig custom resource

To create heterogeneous node pools on an agent hosted cluster, you first need to create the AgentServiceConfig CR with two heterogeneous architecture operating system (OS) images.

Procedure

Run the following command:

$ envsubst <<"EOF" | oc apply -f -
apiVersion: agent-install.openshift.io/v1beta1
kind: AgentServiceConfig
metadata:
 name: agent
spec:
  databaseStorage:
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: <db_volume_name> (1)
  filesystemStorage:
    accessModes:
    - ReadWriteOnce
    resources:
      requests:
        storage: <fs_volume_name> (2)
  osImages:
    - openshiftVersion: <ocp_version> (3)
      version: <ocp_release_version_x86> (4)
      url: <iso_url_x86> (5)
      rootFSUrl: <root_fs_url_x8> (6)
      cpuArchitecture: <arch_x86> (7)
    - openshiftVersion: <ocp_version> (8)
      version: <ocp_release_version_ppc64le> (9)
      url: <iso_url_ppc64le> (10)
      rootFSUrl: <root_fs_url_ppc64le> (11)
      cpuArchitecture: <arch_ppc64le> (12)
EOF

1	Specify the multicluster engine for Kubernetes Operator `agentserviceconfig` config, database volume name.
2	Specify the multicluster engine Operator `agentserviceconfig` config, filesystem volume name.
3	Specify the current version of OKD.
4	Specify the current OKD release version for x86.
5	Specify the ISO URL for x86.
6	Specify the root filesystem URL for X86.
7	Specify the CPU architecture for x86.
8	Specify the current OKD version.
9	Specify the OKD release version for `ppc64le`.
10	Specify the ISO URL for `ppc64le`.
11	Specify the root filesystem URL for `ppc64le`.
12	Specify the CPU architecture for `ppc64le`.

Create an agent cluster

An agent cluster is a cluster that is managed and provisioned using an agent-based approach. An agent cluster can utilize heterogeneous node pools, allowing for different types of worker nodes to be used within the same cluster.

Prerequisites

You used a multi-architecture release image to enable support for heterogeneous node pools when creating a hosted cluster. Find the latest multi-architecture images on the Multi-arch release images page.

Procedure

Create an environment variable for the cluster namespace by running the following command:
```
$ export CLUSTERS_NAMESPACE=<hosted_cluster_namespace>
```
Create an environment variable for the machine classless inter-domain routing (CIDR) notation by running the following command:
```
$ export MACHINE_CIDR=192.168.122.0/24
```
Create the hosted control namespace by running the following command:
```
$ oc create ns <hosted_control_plane_namespace>
```

Create the cluster by running the following command:

$ hcp create cluster agent \
    --name=<hosted_cluster_name> \(1)
    --pull-secret=<pull_secret_file> \(2)
    --agent-namespace=<hosted_control_plane_namespace> \(3)
    --base-domain=<basedomain> \(4)
    --api-server-address=api.<hosted_cluster_name>.<basedomain> \
    --release-image=quay.io/openshift-release-dev/ocp-release:<ocp_release> (5)

1	Specify the hosted cluster name.
2	Specify the pull secret file path.
3	Specify the namespace for the hosted control plane.
4	Specify the base domain for the hosted cluster.
5	Specify the current OKD release version.

Creating heterogeneous node pools

You create heterogeneous node pools by using the NodePool custom resource (CR).

Procedure

To define a NodePool CR, create a YAML file similar to the following example:

envsubst <<"EOF" | oc apply -f -
apiVersion:apiVersion: hypershift.openshift.io/v1beta1
kind: NodePool
metadata:
  name: <hosted_cluster_name>
  namespace: <clusters_namespace>
spec:
  arch: <arch_ppc64le>
  clusterName: <hosted_cluster_name>
  management:
    autoRepair: false
    upgradeType: InPlace
  nodeDrainTimeout: 0s
  nodeVolumeDetachTimeout: 0s
  platform:
    agent:
      agentLabelSelector:
        matchLabels:
          inventory.agent-install.openshift.io/cpu-architecture: <arch_ppc64le> (1)
    type: Agent
  release:
    image: quay.io/openshift-release-dev/ocp-release:<ocp_release>
  replicas: 0
EOF

1	This selector block is selects the agents that match the specified label. To create a node pool of architecture `ppc64le` with zero replicas, specify `ppc64le`. This ensures that it selects only agents from `ppc64le` architecture when it scales.

DNS configuration for hosted control planes

Domain Name Service (DNS) configuration for hosted control planes enables external clients to reach ingress controllers so that they can route traffic to internal components. Configuring this setting ensures that traffic is routed to either ppc64le or x86_64 compute node.

You can point an *.apps.<cluster_name> record to either of the compute nodes where the ingress application is hosted. Or, if you are able to set up a load balancer on top of the compute nodes, point this record to this load balancer. When you are creating a heterogeneous node pool, make sure the compute nodes can reach each other or keep them in the same network.

Creating infrastructure environment resources

For heterogeneous node pools, you must create an infraEnv custom resource (CR) for each architecture. For example, for node pools with x86_64 and ppc64le architectures, create an InfraEnv CR for x86_64 and ppc64le.

Before proceeding, make sure that the operating system (OS) images for both x86_64 and ppc64le architectures are added to the AgentServiceConfig resource. After this, you can use the InfraEnv resources to get the minimal ISO image.

Procedure

Create the InfraEnv resource with x86_64 architecture for heterogeneous node pools by running the following command:

$ envsubst <<"EOF" | oc apply -f -
apiVersion: agent-install.openshift.io/v1beta1
kind: InfraEnv
metadata:
  name: <hosted_cluster_name>-<arch_x86>  (1) (2)
  namespace: <hosted_control_plane_namespace> (3)
spec:
  cpuArchitecture: <arch_x86>
  pullSecretRef:
    name: pull-secret
  sshAuthorizedKey: <ssh_pub_key> (4)
EOF

1	The hosted cluster name.
2	The `x86_64` architecture.
3	The hosted control plane namespace.
4	The ssh public key.

Create the InfraEnv resource with ppc64le architecture for heterogeneous node pools by running the following command:

envsubst <<"EOF" | oc apply -f -
apiVersion: agent-install.openshift.io/v1beta1
kind: InfraEnv
metadata:
  name: <hosted_cluster_name>-<arch_ppc64le>  (1) (2)
  namespace: <hosted_control_plane_namespace> (3)
spec:
  cpuArchitecture: <arch_ppc64le>
  pullSecretRef:
    name: pull-secret
  sshAuthorizedKey: <ssh_pub_key> (4)
EOF

1	The hosted cluster name.
2	The `ppc64le` architecture.
3	The hosted control plane namespace.
4	The ssh public key.

To verify that the InfraEnv resources are created successfully run the following commands:
- Verify that the x86_64 InfraEnv resource is created successfully:
  $ oc describe InfraEnv <hosted_cluster_name>-<arch_x86>
- Verify that the ppc64le InfraEnv resource is created successfully:
  $ oc describe InfraEnv <hosted_cluster_name>-<arch_ppc64le>

Generate a live ISO that allows either a virtual machine or a bare-metal machine to join as agents by running the following commands:

Generate a live ISO for x86_64:

$ oc -n <hosted_control_plane_namespace> get InfraEnv <hosted_cluster_name>-<arch_x86> -ojsonpath="{.status.isoDownloadURL}"

Generate a live ISO for ppc64le:

$ oc -n <hosted_control_plane_namespace> get InfraEnv <hosted_cluster_name>-<arch_ppc64le> -ojsonpath="{.status.isoDownloadURL}"

Adding agents to the heterogeneous cluster

You add agents by manually configuring the machine to boot with a live ISO. You can download the live ISO and use it to boot a bare-metal node or a virtual machine. On boot, the node communicates with the assisted-service and registers as an agent in the same namespace as the InfraEnv resource. When each agent is created, you can optionally set its installation_disk_id and hostname parameters in the specifications. When you are done, approve it to indicate that the agent is ready for use.

Procedure

Obtain a list of agents by running the following command:

oc -n <hosted_control_plane_namespace> get agents

Example output

NAME                                   CLUSTER   APPROVED   ROLE          STAGE
86f7ac75-4fc4-4b36-8130-40fa12602218                        auto-assign
e57a637f-745b-496e-971d-1abbf03341ba                        auto-assign

Patch an agent by running the following command:

oc -n <hosted_control_plane_namespace> patch agent 86f7ac75-4fc4-4b36-8130-40fa12602218 -p '{"spec":{"installation_disk_id":"/dev/sda","approved":true,"hostname":"worker-0.example.krnl.es"}}' --type merge

Patch the second agent by running the following command:

oc -n <hosted_control_plane_namespace> patch agent 23d0c614-2caa-43f5-b7d3-0b3564688baa -p '{"spec":{"installation_disk_id":"/dev/sda","approved":true,"hostname":"worker-1.example.krnl.es"}}' --type merge

Check the agent approval status by running the following command:

oc -n <hosted_control_plane_namespace> get agents

Example output

NAME                                   CLUSTER   APPROVED   ROLE          STAGE
86f7ac75-4fc4-4b36-8130-40fa12602218             true       auto-assign
e57a637f-745b-496e-971d-1abbf03341ba             true       auto-assign

Scaling the node pool

After your agents are approved, you can scale the node pools. The agentLabelSelector value that is configured in the node pool ensures that only matching agents are added to the cluster. This also helps scale down the node pool. To remove specific architecture nodes from the cluster, scale down the corresponding node pool.

Procedure

Scale the node pool by running the following command:

$ oc -n <clusters_namespace> scale nodepool <nodepool_name> --replicas 2

The Cluster API agent provider picks two agents randomly to assign to the hosted cluster. These agents pass through different states and then join the hosted cluster as OKD nodes. The various agent states are binding, discovering, insufficient, installing, installing-in-progress, and added-to-existing-cluster.

Verification

List the agents by running the following command:

$ oc -n <hosted_control_plane_namespace> get agent

Example output

NAME                                   CLUSTER         APPROVED   ROLE          STAGE
4dac1ab2-7dd5-4894-a220-6a3473b67ee6   hypercluster1   true       auto-assign
d9198891-39f4-4930-a679-65fb142b108b                   true       auto-assign
da503cf1-a347-44f2-875c-4960ddb04091   hypercluster1   true       auto-assign

Check the status of a specific scaled agent by running the following command:

$ oc -n <hosted_control_plane_namespace> get agent -o jsonpath='{range .items[*]}BMH: {@.metadata.labels.agent-install\.openshift\.io/bmh} Agent: {@.metadata.name} State: {@.status.debugInfo.state}{"\n"}{end}'

Example output

BMH: ocp-worker-2 Agent: 4dac1ab2-7dd5-4894-a220-6a3473b67ee6 State: binding
BMH: ocp-worker-0 Agent: d9198891-39f4-4930-a679-65fb142b108b State: known-unbound
BMH: ocp-worker-1 Agent: da503cf1-a347-44f2-875c-4960ddb04091 State: insufficient

Once the agents reach the added-to-existing-cluster state, verify that the OKD nodes are ready by running the following command:

$ oc --kubeconfig <hosted_cluster_name>.kubeconfig get nodes

Example output

NAME           STATUS   ROLES    AGE     VERSION
ocp-worker-1   Ready    worker   5m41s   v1.24.0+3882f8f
ocp-worker-2   Ready    worker   6m3s    v1.24.0+3882f8f

Adding workloads to the nodes can reconcile some cluster operators. The following command displays that two machines are created after scaling up the node pool:

$ oc -n <hosted_control_plane_namespace> get machines

Example output

NAME                            CLUSTER               NODENAME       PROVIDERID                                     PHASE     AGE   VERSION
hypercluster1-c96b6f675-m5vch   hypercluster1-b2qhl   ocp-worker-1   agent://da503cf1-a347-44f2-875c-4960ddb04091   Running   15m   4.11.5
hypercluster1-c96b6f675-tl42p   hypercluster1-b2qhl   ocp-worker-2   agent://4dac1ab2-7dd5-4894-a220-6a3473b67ee6   Running   15m   4.11.5