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In OpenShift Container Platform version 4.11, you can install a customized cluster on Red Hat OpenStack Platform (RHOSP). To customize the installation, modify parameters in the install-config.yaml before you install the cluster.

Prerequisites

Resource guidelines for installing OpenShift Container Platform on RHOSP

To support an OpenShift Container Platform installation, your Red Hat OpenStack Platform (RHOSP) quota must meet the following requirements:

Table 1. Recommended resources for a default OpenShift Container Platform cluster on RHOSP
Resource Value

Floating IP addresses

3

Ports

15

Routers

1

Subnets

1

RAM

112 GB

vCPUs

28

Volume storage

275 GB

Instances

7

Security groups

3

Security group rules

60

Server groups

2 - plus 1 for each additional availability zone in each machine pool

A cluster might function with fewer than recommended resources, but its performance is not guaranteed.

If RHOSP object storage (Swift) is available and operated by a user account with the swiftoperator role, it is used as the default backend for the OpenShift Container Platform image registry. In this case, the volume storage requirement is 175 GB. Swift space requirements vary depending on the size of the image registry.

By default, your security group and security group rule quotas might be low. If you encounter problems, run openstack quota set --secgroups 3 --secgroup-rules 60 <project> as an administrator to increase them.

An OpenShift Container Platform deployment comprises control plane machines, compute machines, and a bootstrap machine.

Control plane machines

By default, the OpenShift Container Platform installation process creates three control plane machines.

Each machine requires:

  • An instance from the RHOSP quota

  • A port from the RHOSP quota

  • A flavor with at least 16 GB memory, 4 vCPUs, and 100 GB storage space

Compute machines

By default, the OpenShift Container Platform installation process creates three compute machines.

Each machine requires:

  • An instance from the RHOSP quota

  • A port from the RHOSP quota

  • A flavor with at least 8 GB memory, 2 vCPUs, and 100 GB storage space

Compute machines host the applications that you run on OpenShift Container Platform; aim to run as many as you can.

Bootstrap machine

During installation, a bootstrap machine is temporarily provisioned to stand up the control plane. After the production control plane is ready, the bootstrap machine is deprovisioned.

The bootstrap machine requires:

  • An instance from the RHOSP quota

  • A port from the RHOSP quota

  • A flavor with at least 16 GB memory, 4 vCPUs, and 100 GB storage space

Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.11, you require access to the internet to install your cluster.

You must have internet access to:

  • Access OpenShift Cluster Manager Hybrid Cloud Console to download the installation program and perform subscription management. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster.

  • Access Quay.io to obtain the packages that are required to install your cluster.

  • Obtain the packages that are required to perform cluster updates.

If your cluster cannot have direct internet access, you can perform a restricted network installation on some types of infrastructure that you provision. During that process, you download the required content and use it to populate a mirror registry with the installation packages. With some installation types, the environment that you install your cluster in will not require internet access. Before you update the cluster, you update the content of the mirror registry.

Enabling Swift on RHOSP

Swift is operated by a user account with the swiftoperator role. Add the role to an account before you run the installation program.

If the Red Hat OpenStack Platform (RHOSP) object storage service, commonly known as Swift, is available, OpenShift Container Platform uses it as the image registry storage. If it is unavailable, the installation program relies on the RHOSP block storage service, commonly known as Cinder.

If Swift is present and you want to use it, you must enable access to it. If it is not present, or if you do not want to use it, skip this section.

Prerequisites
  • You have a RHOSP administrator account on the target environment.

  • The Swift service is installed.

  • On Ceph RGW, the account in url option is enabled.

Procedure

To enable Swift on RHOSP:

  1. As an administrator in the RHOSP CLI, add the swiftoperator role to the account that will access Swift:

    $ openstack role add --user <user> --project <project> swiftoperator

Your RHOSP deployment can now use Swift for the image registry.

Configuring an image registry with custom storage on clusters that run on RHOSP

After you install a cluster on Red Hat OpenStack Platform (RHOSP), you can use a Cinder volume that is in a specific availability zone for registry storage.

Procedure
  1. Create a YAML file that specifies the storage class and availability zone to use. For example:

    apiVersion: storage.k8s.io/v1
    kind: StorageClass
    metadata:
      name: custom-csi-storageclass
    provisioner: cinder.csi.openstack.org
    volumeBindingMode: WaitForFirstConsumer
    allowVolumeExpansion: true
    parameters:
      availability: <availability_zone_name>

    OpenShift Container Platform does not verify the existence of the availability zone you choose. Verify the name of the availability zone before you apply the configuration.

  2. From a command line, apply the configuration:

    $ oc apply -f <storage_class_file_name>
    Example output
    storageclass.storage.k8s.io/custom-csi-storageclass created
  3. Create a YAML file that specifies a persistent volume claim (PVC) that uses your storage class and the openshift-image-registry namespace. For example:

    apiVersion: v1
    kind: PersistentVolumeClaim
    metadata:
      name: csi-pvc-imageregistry
      namespace: openshift-image-registry (1)
      annotations:
        imageregistry.openshift.io: "true"
    spec:
      accessModes:
      - ReadWriteOnce
      volumeMode: Filesystem
      resources:
        requests:
          storage: 100Gi (2)
      storageClassName: <your_custom_storage_class> (3)
    1 Enter the namespace openshift-image-registry. This namespace allows the Cluster Image Registry Operator to consume the PVC.
    2 Optional: Adjust the volume size.
    3 Enter the name of the storage class that you created.
  4. From a command line, apply the configuration:

    $ oc apply -f <pvc_file_name>
    Example output
    persistentvolumeclaim/csi-pvc-imageregistry created
  5. Replace the original persistent volume claim in the image registry configuration with the new claim:

    $ oc patch configs.imageregistry.operator.openshift.io/cluster --type 'json' -p='[{"op": "replace", "path": "/spec/storage/pvc/claim", "value": "csi-pvc-imageregistry"}]'
    Example output
    config.imageregistry.operator.openshift.io/cluster patched

    Over the next several minutes, the configuration is updated.

Verification

To confirm that the registry is using the resources that you defined:

  1. Verify that the PVC claim value is identical to the name that you provided in your PVC definition:

    $ oc get configs.imageregistry.operator.openshift.io/cluster -o yaml
    Example output
    ...
    status:
        ...
        managementState: Managed
        pvc:
          claim: csi-pvc-imageregistry
    ...
  2. Verify that the status of the PVC is Bound:

    $ oc get pvc -n openshift-image-registry csi-pvc-imageregistry
    Example output
    NAME                   STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS             AGE
    csi-pvc-imageregistry  Bound    pvc-72a8f9c9-f462-11e8-b6b6-fa163e18b7b5   100Gi      RWO            custom-csi-storageclass  11m

Verifying external network access

The OpenShift Container Platform installation process requires external network access. You must provide an external network value to it, or deployment fails. Before you begin the process, verify that a network with the external router type exists in Red Hat OpenStack Platform (RHOSP).

Procedure
  1. Using the RHOSP CLI, verify the name and ID of the 'External' network:

    $ openstack network list --long -c ID -c Name -c "Router Type"</