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Deploying hosted control planes on IBM Z

You can deploy hosted control planes on IBM Z by configuring a cluster to function as a management cluster. The management cluster is the OpenShift Container Platform cluster where the control planes are hosted. The management cluster is also known as the hosting cluster.

note

The management cluster is not the managed cluster. A managed cluster is a cluster that the hub cluster manages. The management cluster can run on either the x86_64 architecture, supported beginning with OpenShift Container Platform 4.17 and multicluster engine for Kubernetes Operator 2.7, or the s390x architecture, supported beginning with OpenShift Container Platform 4.20 and multicluster engine for Kubernetes Operator 2.10.

You can convert a managed cluster to a management cluster by using the hypershift add-on to deploy the HyperShift Operator on that cluster. Then, you can start to create the hosted cluster.

The multicluster engine Operator supports only the default local-cluster, which is a hub cluster that is managed, and the hub cluster as the management 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 Z system host must be started with the PXE or ISO images that are provided by the central infrastructure management. 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 Operator installs the Agent Cluster API provider in the hosted control plane namespace.

Prerequisites to configure hosted control planes on IBM Z​

Ensure you meet the prerequisites to configure hosted control planes on IBM Z.

  • The multicluster engine for Kubernetes Operator version 2.7 or later must be installed on an OpenShift Container Platform cluster. You can install multicluster engine Operator as an Operator from the OpenShift Container Platform OperatorHub.
  • The multicluster engine Operator must have at least one managed OpenShift Container Platform cluster. The local-cluster is automatically imported in multicluster engine Operator 2.7 and later. For more information about the local-cluster, see Advanced configuration in the Red Hat Advanced Cluster Management 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 three 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".
note

The management cluster can run on either the x86_64 architecture, supported beginning with OpenShift Container Platform 4.17 and multicluster engine for Kubernetes Operator 2.7, or the s390x architecture, supported beginning with OpenShift Container Platform 4.20 and multicluster engine for Kubernetes Operator 2.10.

Additional resources

IBM Z infrastructure requirements​

The Agent platform does not create any infrastructure, but requires several resources for infrastructure.

  • Agents: An Agent represents a host that is booted with a discovery image, or PXE image and is ready to be provisioned as an OpenShift Container Platform node.
  • DNS: The API and Ingress endpoints must be routable.

The hosted control planes feature is enabled by default. If you disabled the feature and want to manually enable it, or if you need to disable the feature, see "Enabling or disabling the hosted control planes feature".

DNS configuration for hosted control planes on IBM Z​

The API server for the hosted cluster is exposed as a NodePort service. A DNS entry must exist for the api.<hosted_cluster_name>.<base_domain> 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 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
api-int               IN A 1xx.2x.2xx.1xx
;
;
*.apps        IN A 1xx.2x.2xx.1xx
;
;EOF

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

For IBM z/VM, add IP addresses that correspond to the IP address of the agent.

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 differs from the internal endpoint that gets 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 bind 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 postinstallation operations, by entering a domain name in the kubeAPIServerDNSName parameter of a HostedCluster object.

Prerequisites

  • You have a valid TLS certificate that covers the DNS name that you set in the kubeAPIServerDNSName parameter.
  • You have a resolvable DNS name URI that can reach and point to the correct address.

Procedure

  • In the specification for the HostedCluster object, add the kubeAPIServerDNSName parameter 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: <custom_address>

    The value for the kubeAPIServerDNSName parameter must be a valid and addressable domain.

    After you define the kubeAPIServerDNSName parameter and specify the certificate, the Control Plane Operator controllers create a kubeconfig file named custom-admin-kubeconfig, where the file gets stored in the HostedControlPlane namespace. The generation of certificates happen 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 defined new server in the kubeAPIServerDNSName parameter.

    A reference for the custom kubeconfig file exists in the status parameter as CustomKubeconfig of the HostedCluster object. The CustomKubeConfig parameter is optional, and you can add the parameter only if the kubeAPIServerDNSName parameter is not empty. After you set the CustomKubeConfig parameter, the parameter 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 parameter during postinstallation operations, deletion of all related secrets and status references occur.

    note

    Defining a custom DNS name does not directly impact the data plane, so no expected rollouts occur. The HostedControlPlane namespace receives the changes from the HyperShift Operator and deletes the corresponding parameters.

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

Creating a hosted cluster on bare metal for IBM Z​

On bare-metal infrastructure, you can create or import a hosted cluster. After you enable the Assisted Installer 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. The Agent Cluster API provider connects a management cluster that hosts the control plane and a hosted cluster that consists of only the compute nodes.

Prerequisites

  • Each hosted cluster must have a cluster-wide unique name. A hosted cluster name cannot be the same as any existing managed cluster. Otherwise, the multicluster engine Operator cannot manage the hosted cluster.
  • Do not use the word clusters as a hosted cluster name.
  • You cannot create a hosted cluster in the namespace of a multicluster engine Operator managed cluster.
  • For best security and management practices, create a hosted cluster separate from other hosted clusters.
  • Verify that you have a default storage class configured for your cluster. Otherwise, you might see pending persistent volume claims (PVCs).

Procedure

  1. 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. The HyperShift Operator creates the namespace. During the hosted cluster creation process on bare-metal infrastructure, a generated Cluster API provider role requires that the namespace already exists.

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

    $ hcp create cluster agent \
      --name=<hosted_cluster_name> \
      --pull-secret=<path_to_pull_secret> \
      --agent-namespace=<hosted_control_plane_namespace> \
      --base-domain=<base_domain> \
      --api-server-address=api.<hosted_cluster_name>.<base_domain> \
      --etcd-storage-class=<etcd_storage_class> \
      --ssh-key=<path_to_ssh_key> \
      --namespace=<hosted_cluster_namespace> \
      --control-plane-availability-policy=HighlyAvailable \
      --release-image=quay.io/openshift-release-dev/ocp-release:<ocp_release_image>-multi \
      --node-pool-replicas=<node_pool_replica_count> \
      --disable-cluster-capabilities=<capability> \
      --enable-cluster-capabilities=<capability> \
      --render \
      --render-sensitive  > hosted-cluster-config.yaml

    where:

    • --name specifies the name of your hosted cluster, such as example.
    • --pull-secret specifies the path to your pull secret, such as /user/name/pullsecret.
    • --agent-namespace specifies your hosted control plane namespace, such as clusters-example. Ensure that agents are available in this namespace by using the oc get agent -n <hosted_control_plane_namespace> command.
    • --base-domain specifies your base domain, such as krnl.es.
    • --api-server-address specifies the IP address that gets 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.
    • --etcd-storage-class specifies the etcd storage class name, such as lvm-storageclass.
    • --ssh-key specifies the path to your SSH public key. The default file path is ~/.ssh/id_rsa.pub.
    • --namespace specifies your hosted cluster namespace.
    • --control-plane-availability-policy specifies the availability policy for the hosted control plane components. Supported options are SingleReplica and HighlyAvailable. The default value is HighlyAvailable.
    • --release-image specifies the supported OpenShift Container Platform version that you want to use, such as 4.22.0-multi. If you are using a disconnected environment, replace <ocp_release_image> with the digest image. To extract the OpenShift Container Platform release image digest, see "Extracting the release image digest".
    • --node-pool-replicas specifies the node pool replica count, such as 3. You must specify the replica count as 0 or greater to create the same number of replicas. Otherwise, you do not create node pools.
    • --disable-cluster-capabilities specifies that you want to disable optional capabilities in the hosted cluster. This flag is optional. For more information, see "Capabilities for hosted clusters".
    • --enable-cluster-capabilities specifies that you want to enable optional capabilities in the hosted cluster. This flag is optional. For more information, see "Capabilities for hosted clusters".

  3. Apply the changes to the hosted cluster configuration file by entering the following command:

    $ oc apply -f hosted_cluster_config.yaml

  4. Check for the creation of the hosted cluster, node pools, and pods by entering the following commands:

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

  5. Confirm that the hosted cluster is ready. The status of Available: True indicates the readiness of the control plane.

Additional resources

Capabilities for hosted clusters​

To reduce resource consumption and prevent unnecessary Operators and operands from being deployed, administrators can enable or disable optional OpenShift Container Platform components when they create a hosted cluster.

When capabilities are not specified on a HostedCluster resource, the cluster uses the OpenShift Container Platform version’s DefaultCapabilitySet settings, excluding the baremetal capability. As a result, most optional components are enabled by default.

warning

Capabilities are immutable after cluster creation. You cannot change them after you create the HostedCluster resource.

Capabilities that you can enable or disable for a hosted cluster​

Familiarize yourself with the supported capabilities that you can enable or disable for a HostedCluster resource.

The capabilities are described in the following table:

CapabilityDescription
ImageRegistryThe OpenShift Image Registry Operator and its operands, including cloud storage infrastructure, such as S3 buckets and Identity and Access Management (IAM) users.
openshift-samplesThe OpenShift Samples Operator, which manages example ImageStreams and templates.
InsightsThe Insights Operator, which collects and uploads cluster telemetry data.
baremetalThe Bare Metal Infrastructure Operator. This capability is excluded from the default set. If needed, you must explicitly enable it.
ConsoleThe OpenShift Web Console Operator and its operands.
NodeTuningThe Node Tuning Operator, which manages node-level performance tuning by using TuneD and performance profiles.
IngressThe OpenShift Ingress Operator, which manages the default router of the cluster.

The following rules apply when you combine capability settings:

No overlap
A capability cannot be in both the enabled and disabled lists simultaneously.
Console requires Ingress
You can disable the Ingress capability only if the Console capability is also disabled because the console depends on Ingress.
Version requirement
You must use OpenShift Container Platform 4.20 or later to disable any of the following capabilities: openshift-samples, Insights, Console, NodeTuning, and Ingress. You can disable ImageRegistry and baremetal on versions earlier than 4.20.
Bare metal default exclusion
The baremetal capability is excluded from the default set. You can add it to the cluster by explicitly enabling it.

Setting capabilities for a hosted cluster​

To reduce unnecessary resource consumption, you can control which optional capabilities are enabled for a hosted cluster when you create the cluster.

warning

Capabilities are immutable after cluster creation. You cannot change them after you create the HostedCluster resource.

You can specify which capabilities are enabled by either using the hcp command-line interface (CLI) or by setting the HostedCluster manifest.

Procedure

  • To specify which capabilities are enabled in a hosted cluster by using the CLI, you can add the --disable-cluster-capabilities flag, the --enable-cluster-capabilities flag, or both. The following example shows how to disable the ImageRegistry, Console, and Ingress capabilities and enable the baremetal capability while you create a hosted cluster on AWS by using the hcp command-line interface:

    $ hcp create cluster aws \
        --name my-hosted-cluster \
        --disable-cluster-capabilities=ImageRegistry,Console,Ingress \
        --enable-cluster-capabilities=baremetal

    You can specify multiple capabilities as a comma-separated list. The supported values are as follows:

    • ImageRegistry
    • openshift-samples
    • Insights
    • baremetal
    • Console
    • NodeTuning
    • Ingress

  • To specify which capabilities are enabled in a hosted cluster by using the HostedCluster manifest at cluster creation time, see the following examples:

    • To directly disable capabilities in a hosted cluster, add the spec.capabilities.disabled section in the HostedCluster resource: 
      apiVersion: hypershift.openshift.io/v1beta1
      kind: HostedCluster
      metadata:
        name: my-hosted-cluster
        namespace: my-cluster-namespace
      spec:
        capabilities:
          disabled:
            - ImageRegistry
            - Console
            - Ingress
        # ...
    • To explicitly enable a capability that is not part of the default set of capabilities, such as the baremetal capability, see the following example: 
      apiVersion: hypershift.openshift.io/v1beta1
      kind: HostedCluster
      metadata:
        name: my-hosted-cluster
        namespace: my-cluster-namespace
      spec:
        capabilities:
          enabled:
            - baremetal
        # ...
    • You can use both enabled and disabled if no capabilities are in both lists. See the following example: 
      apiVersion: hypershift.openshift.io/v1beta1
      kind: HostedCluster
      metadata:
        name: my-hosted-cluster
        namespace: my-cluster-namespace
      spec:
        capabilities:
          enabled:
            - baremetal
          disabled:
            - ImageRegistry
            - openshift-samples
        # ...

Creating an InfraEnv resource for hosted control planes on IBM Z​

Before you can create a hosted cluster, you need an InfraEnv resource, which is the environment where hosts that are booted with PXE images can join as agents. In this case, the agents are created in the same namespace as your hosted control plane.

Procedure

  1. Create a YAML file to contain the configuration. See the following example: 
    apiVersion: agent-install.openshift.io/v1beta1
    kind: InfraEnv
    metadata:
      name: <hosted_cluster_name>
      namespace: <hosted_control_plane_namespace>
    spec:
      cpuArchitecture: s390x
      pullSecretRef:
        name: pull-secret
      sshAuthorizedKey: <ssh_public_key>
  2. Save the file as infraenv-config.yaml.
  3. Apply the configuration by entering the following command: 
    $ oc apply -f infraenv-config.yaml
  4. To fetch the URL to download the PXE or ISO images, such as, initrd.img, kernel.img, or rootfs.img, which allows IBM Z machines to join as agents, enter the following command: 
    $ oc -n <hosted_control_plane_namespace> get InfraEnv <hosted_cluster_name> -o json

Adding IBM Z KVM as agents​

To attach compute nodes to a hosted control plane, create agents that help you to scale the node pool.

Adding agents in an IBM Z environment requires additional steps, which are described in detail in this section.

Unless stated otherwise, this procedure applies to both z/VM and RHEL KVM installations on IBM Z and IBM LinuxONE.

For IBM Z with KVM, run the following command to start your IBM Z environment with the downloaded PXE images from the InfraEnv resource. After the Agents are created, the host communicates with the Assisted Service and registers in the same namespace as the InfraEnv resource on the management cluster.

Procedure

  1. Run the following command:

    virt-install \
       --name "<vm_name>" \
       --autostart \
       --ram=16384 \
       --cpu host \
       --vcpus=4 \
       --location "<path_to_kernel_initrd_image>,kernel=kernel.img,initrd=initrd.img" \
       --disk <qcow_image_path> \
       --network network:macvtap-net,mac=<mac_address> \
       --graphics none \
       --noautoconsole \
       --wait=-1
       --extra-args "rd.neednet=1 nameserver=<nameserver>   coreos.live.rootfs_url=http://<http_server>/rootfs.img random.trust_cpu=on rd.luks.options=discard ignition.firstboot ignition.platform.id=metal console=tty1 console=ttyS1,115200n8 coreos.inst.persistent-kargs=console=tty1 console=ttyS1,115200n8"
    • --name specifies the name of the virtual machine.
    • --location specifies the location of the kernel_initrd_image file.
    • --disk specifies the disk image path.
    • --network specifies the Mac address.
    • --extra-args specifies the server name of the agents.

  2. For ISO boot, download ISO from the InfraEnv resource and boot the nodes by running the following command:

    virt-install \
      --name "<vm_name>" \
      --autostart \
      --memory=16384 \
      --cpu host \
      --vcpus=4 \
      --network network:macvtap-net,mac=<mac_address> \
      --cdrom "<path_to_image.iso>" \
      --disk <qcow_image_path> \
      --graphics none \
      --noautoconsole \
      --os-variant <os_version> \
      --wait=-1
    • --name specifies the name of the virtual machine.
    • --network specifies the Mac address.
    • --cdrom specifies the location of the image.iso file.
    • --os-variant specifies the operating system version that you are using.

Adding IBM Z LPAR as agents​

To attach compute nodes to a hosted control plane, create agents that help you to scale the node pool.

Adding agents in an IBM Z environment requires additional steps, which are described in detail in this section.

Unless stated otherwise, this procedure applies to both z/VM and RHEL KVM installations on IBM Z and IBM LinuxONE.

You can add the Logical Partition (LPAR) on IBM Z or IBM LinuxONE as a compute node to a hosted control plane.

Procedure

  1. Create a boot parameter file for the agents:

    Example parameter file
    rd.neednet=1 cio_ignore=all,!condev \
    console=ttysclp0 \
    ignition.firstboot ignition.platform.id=metal
    coreos.live.rootfs_url=http://<http_server>/rhcos-<version>-live-rootfs.<architecture>.img \
    coreos.inst.persistent-kargs=console=ttysclp0
    ip=<ip>::<gateway>:<netmask>::<interface>:none nameserver=<dns> \
    rd.znet=qeth,<network_adaptor_range>,layer2=1
    rd.<disk_type>=<adapter> \
    zfcp.allow_lun_scan=0
    ai.ip_cfg_override=1 \
    random.trust_cpu=on rd.luks.options=discard

    where:

    coreos.live.rootfs_url
    For the coreos.live.rootfs_url artifact, specify the matching rootfs artifact for the kernel and initramfs that you are starting. Only HTTP and HTTPS protocols are supported.
    ip
    For the ip parameter, manually assign the IP address, as described in "Installing a cluster with z/VM on IBM Z and IBM LinuxONE".
    rd
    For installations on DASD-type disks, use rd.dasd to specify the DASD where Red Hat Enterprise Linux CoreOS (RHCOS) is to be installed. For installations on FCP-type disks, use rd.zfcp=<adapter>,<wwpn>,<lun> to specify the FCP disk where RHCOS is to be installed.
    ai.ip_cfg_override
    Specify this parameter when you use an Open Systems Adapter (OSA) or HiperSockets.

  2. Download the .ins and initrd.img.addrsize files from the InfraEnv resource. By default, the URL for the .ins and initrd.img.addrsize files is not available in the InfraEnv resource. You must edit the URL to fetch those artifacts.

    1. Update the kernel URL endpoint to include ins-file by running the followign command:

      $ curl -k -L -o generic.ins "< url for ins-file >"
      Example URL
      https://…/boot-artifacts/ins-file?arch=s390x&version=4.17.0

    2. Update the initrd URL endpoint to include s390x-initrd-addrsize:

      Example URL
      https://…./s390x-initrd-addrsize?api_key=<api-key>&arch=s390x&version=4.17.0

  3. Transfer the initrd, kernel, generic.ins, and initrd.img.addrsize parameter files to the file server. For more information about how to transfer the files with FTP and boot, see "Installing in an LPAR".

  4. Start the machine.

  5. Repeat the procedure for all other machines in the cluster.

Additional resources

Adding IBM z/VM as agents​

If you want to use a static IP for z/VM guest, you must configure the NMStateConfig attribute for the z/VM agent so that the IP parameter persists in the second start.

Complete the following steps to start your IBM Z environment with the downloaded PXE images from the InfraEnv resource. After the Agents are created, the host communicates with the Assisted Service and registers in the same namespace as the InfraEnv resource on the management cluster.

Procedure

  1. Update the parameter file to add the rootfs_url, network_adaptor and disk_type values.

    Example parameter file
    rd.neednet=1 cio_ignore=all,!condev \
    console=ttysclp0  \
    ignition.firstboot ignition.platform.id=metal \
    coreos.live.rootfs_url=http://<http_server>/rhcos-<version>-live-rootfs.<architecture>.img \
    coreos.inst.persistent-kargs=console=ttysclp0
    ip=<ip>::<gateway>:<netmask>::<interface>:none nameserver=<dns> \
    rd.znet=qeth,<network_adaptor_range>,layer2=1
    rd.<disk_type>=<adapter> \
    zfcp.allow_lun_scan=0
    ai.ip_cfg_override=1 \

    where:

    coreos.live.rootfs_url
    For the coreos.live.rootfs_url artifact, specify the matching rootfs artifact for the kernel and initramfs that you are starting. Only HTTP and HTTPS protocols are supported.
    ip
    For the ip parameter, manually assign the IP address, as described in "Installing a cluster with z/VM on IBM Z and IBM LinuxONE".
    rd
    For installations on DASD-type disks, use rd.dasd to specify the DASD where Red Hat Enterprise Linux CoreOS (RHCOS) is to be installed. For installations on FCP-type disks, use rd.zfcp=<adapter>,<wwpn>,<lun> to specify the FCP disk where RHCOS is to be installed.
    note

    For FCP multipath configurations, provide two disks instead of one.

    Example 
    rd.zfcp=<adapter1>,<wwpn1>,<lun1> \
    rd.zfcp=<adapter2>,<wwpn2>,<lun2>
    ai.ip_cfg_override
    Specify this parameter when you use an Open Systems Adapter (OSA) or HiperSockets.

  2. Move initrd, kernel images, and the parameter file to the guest VM by running the following commands:

    vmur pun -r -u -N kernel.img $INSTALLERKERNELLOCATION/<image name>
    vmur pun -r -u -N generic.parm $PARMFILELOCATION/paramfilename
    vmur pun -r -u -N initrd.img $INSTALLERINITRAMFSLOCATION/<image name>

  3. Run the following command from the guest VM console:

    cp ipl c

  4. To list the agents and their properties, enter the following command:

    $ oc -n <hosted_control_plane_namespace> get agents
    Example output
    NAME    CLUSTER APPROVED    ROLE    STAGE
    50c23cda-cedc-9bbd-bcf1-9b3a5c75804d    auto-assign
    5e498cd3-542c-e54f-0c58-ed43e28b568a    auto-assign

  5. Run the following command to approve the agent.

    $ oc -n <hosted_control_plane_namespace> patch agent \
      50c23cda-cedc-9bbd-bcf1-9b3a5c75804d -p \
      '{"spec":{"installation_disk_id":"/dev/sda","approved":true,"hostname":"worker-zvm-0.hostedn.example.com"}}' \
      --type merge

    Optionally, you can set the agent ID <installation_disk_id> and <hostname> in the specification.

  6. Run the following command to verify that the agents are approved:

    $ oc -n <hosted_control_plane_namespace> get agents
    Example output
    NAME                                            CLUSTER     APPROVED   ROLE          STAGE
    50c23cda-cedc-9bbd-bcf1-9b3a5c75804d             true       auto-assign
    5e498cd3-542c-e54f-0c58-ed43e28b568a             true       auto-assign

Scaling the NodePool object for a hosted cluster on IBM Z​

The NodePool object is created when you create a hosted cluster. By scaling the NodePool object, you can add more compute nodes to the hosted control plane.

When you scale up a node pool, a machine is created. The Cluster API provider finds an Agent that is approved, is passing validations, is not currently in use, and meets the requirements that are specified in the node pool specification. You can monitor the installation of an Agent by checking its status and conditions.

Procedure

  1. Run the following command to scale the NodePool object to two nodes:

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

    The Cluster API agent provider randomly picks two agents that are then assigned to the hosted cluster. Those agents go through different states and finally join the hosted cluster as OpenShift Container Platform nodes. The agents pass through the transition phases in the following order:

    • binding
    • discovering
    • insufficient
    • installing
    • installing-in-progress
    • added-to-existing-cluster

  2. Run the following command to see the status of a specific scaled agent:

    $ 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: Agent: 50c23cda-cedc-9bbd-bcf1-9b3a5c75804d State: known-unbound
    BMH: Agent: 5e498cd3-542c-e54f-0c58-ed43e28b568a State: insufficient

  3. Run the following command to see the transition phases:

    $ oc -n <hosted_control_plane_namespace> get agent
    Example output
    NAME                                   CLUSTER           APPROVED       ROLE        STAGE
    50c23cda-cedc-9bbd-bcf1-9b3a5c75804d   hosted-forwarder   true          auto-assign
    5e498cd3-542c-e54f-0c58-ed43e28b568a                      true          auto-assign
    da503cf1-a347-44f2-875c-4960ddb04091   hosted-forwarder   true          auto-assign

  4. Run the following command to generate the kubeconfig file to access the hosted cluster:

    $ hcp create kubeconfig \
      --namespace <clusters_namespace> \
      --name <hosted_cluster_namespace> > <hosted_cluster_name>.kubeconfig

  5. After the agents reach the added-to-existing-cluster state, verify that you can see the OpenShift Container Platform nodes by entering the following command:

    $ oc --kubeconfig <hosted_cluster_name>.kubeconfig get nodes
    Example output
    NAME                             STATUS   ROLES    AGE      VERSION
    worker-zvm-0.hostedn.example.com Ready    worker   5m41s    v1.24.0+3882f8f
    worker-zvm-1.hostedn.example.com Ready    worker   6m3s     v1.24.0+3882f8f

    Cluster Operators start to reconcile by adding workloads to the nodes.

  6. Enter the following command to verify that two machines were created when you scaled up the NodePool object:

    $ oc -n <hosted_control_plane_namespace> get machine.cluster.x-k8s.io
    Example output
    NAME                                CLUSTER  NODENAME PROVIDERID     PHASE     AGE   VERSION
    hosted-forwarder-79558597ff-5tbqp   hosted-forwarder-crqq5   worker-zvm-0.hostedn.example.com   agent://50c23cda-cedc-9bbd-bcf1-9b3a5c75804d   Running   41h   4.15.0
    hosted-forwarder-79558597ff-lfjfk   hosted-forwarder-crqq5   worker-zvm-1.hostedn.example.com   agent://5e498cd3-542c-e54f-0c58-ed43e28b568a   Running   41h   4.15.0

  7. Run the following command to check the cluster version:

    $ oc --kubeconfig <hosted_cluster_name>.kubeconfig get clusterversion,co
    Example output
    NAME                                         VERSION       AVAILABLE   PROGRESSING   SINCE   STATUS
    clusterversion.config.openshift.io/version   4.15.0-ec.2   True        False         40h     Cluster version is 4.15.0-ec.2

  8. Run the following command to check the cluster operator status:

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

    For each component of your cluster, the output shows the following cluster operator statuses: NAME, VERSION, AVAILABLE, PROGRESSING, DEGRADED, SINCE, and MESSAGE.

    For an output example, see "Initial Operator configuration".