You can customize and install an OpenShift Container Platform cluster on Red Hat Virtualization (RHV), similar to the one shown in the following diagram.

Diagram of an OpenShift Container Platform cluster on a RHV cluster

The installation program uses installer-provisioned infrastructure to automate creating and deploying the cluster.

To install a customized cluster, you prepare the environment and perform the following steps:

  1. Create an installation configuration file, the install-config.yaml file, by running the installation program and answering its prompts.

  2. Inspect and modify parameters in the install-config.yaml file.

  3. Make a working copy of the install-config.yaml file.

  4. Run the installation program with a copy of the install-config.yaml file.

Then, the installation program creates the OpenShift Container Platform cluster.

For an alternative to installing a customized cluster, see Installing a default cluster.

This installation program is available for Linux and macOS only.

Prerequisites

Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.8, you require access to the internet to install your cluster.

You must have internet access to:

  • Access the Red Hat OpenShift Cluster Manager page 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 content that is required and use it to populate a mirror registry with the packages that you need to install a cluster and generate the installation program. 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.

Requirements for the RHV environment

To install and run an OpenShift Container Platform version 4.8 cluster, the RHV environment must meet the following requirements.

Not meeting these requirements can cause the installation or process to fail. Additionally, not meeting these requirements can cause the OpenShift Container Platform cluster to fail days or weeks after installation.

The following requirements for CPU, memory, and storage resources are based on default values multiplied by the default number of virtual machines the installation program creates. These resources must be available in addition to what the RHV environment uses for non-OpenShift Container Platform operations.

By default, the installation program creates seven virtual machines during the installation process. First, it creates a bootstrap virtual machine to provide temporary services and a control plane while it creates the rest of the OpenShift Container Platform cluster. When the installation program finishes creating the cluster, deleting the bootstrap machine frees up its resources.

If you increase the number of virtual machines in the RHV environment, you must increase the resources accordingly.

Requirements
  • The RHV version is 4.4.

  • The RHV environment has one data center whose state is Up.

  • The RHV data center contains an RHV cluster.

  • The RHV cluster has the following resources exclusively for the OpenShift Container Platform cluster:

    • Minimum 28 vCPUs: four for each of the seven virtual machines created during installation.

    • 112 GiB RAM or more, including:

      • 16 GiB or more for the bootstrap machine, which provides the temporary control plane.

      • 16 GiB or more for each of the three control plane machines which provide the control plane.

      • 16 GiB or more for each of the three compute machines, which run the application workloads.

  • The RHV storage domain must meet these etcd backend performance requirements.

  • For affinity group support:

    One physical machine per worker or control plane. Workers and control planes can be on the same physical machine. For example, if you have three workers and three control planes, you need three physical machines. If you have four workers and three control planes, you need four physical machines.

    • For hard anti-affinity (default): A minimum of three physical machines. For more than three worker nodes, one physical machine per worker or control plane. Workers and control planes can be on the same physical machine.

    • For custom affinity groups: Ensure that the resources are appropriate for the affinity group rules that you define.

  • In production environments, each virtual machine must have 120 GiB or more. Therefore, the storage domain must provide 840 GiB or more for the default OpenShift Container Platform cluster. In resource-constrained or non-production environments, each virtual machine must have 32 GiB or more, so the storage domain must have 230 GiB or more for the default OpenShift Container Platform cluster.

  • To download images from the Red Hat Ecosystem Catalog during installation and update procedures, the RHV cluster must have access to an internet connection. The Telemetry service also needs an internet connection to simplify the subscription and entitlement process.

  • The RHV cluster must have a virtual network with access to the REST API on the RHV Manager. Ensure that DHCP is enabled on this network, because the VMs that the installer creates obtain their IP address by using DHCP.

  • A user account and group with the following least privileges for installing and managing an OpenShift Container Platform cluster on the target RHV cluster:

    • DiskOperator

    • DiskCreator

    • UserTemplateBasedVm

    • TemplateOwner

    • TemplateCreator

    • ClusterAdmin on the target cluster

Apply the principle of least privilege: Avoid using an administrator account with SuperUser privileges on RHV during the installation process. The installation program saves the credentials you provide to a temporary ovirt-config.yaml file that might be compromised.

Verifying the requirements for the RHV environment

Verify that the RHV environment meets the requirements to install and run an OpenShift Container Platform cluster. Not meeting these requirements can cause failures.

These requirements are based on the default resources the installation program uses to create control plane and compute machines. These resources include vCPUs, memory, and storage. If you change these resources or increase the number of OpenShift Container Platform machines, adjust these requirements accordingly.

Procedure
  1. Check that the RHV version supports installation of OpenShift Container Platform version 4.8.

    1. In the RHV Administration Portal, click the ? help icon in the upper-right corner and select About.

    2. In the window that opens, make a note of the RHV Software Version.

    3. Confirm that the RHV version is 4.4. For more information about supported version combinations, see Support Matrix for OpenShift Container Platform on RHV.

  2. Inspect the data center, cluster, and storage.

    1. In the RHV Administration Portal, click ComputeData Centers.

    2. Confirm that the data center where you plan to install OpenShift Container Platform is accessible.

    3. Click the name of that data center.

    4. In the data center details, on the Storage tab, confirm the storage domain where you plan to install OpenShift Container Platform is Active.

    5. Record the Domain Name for use later on.

    6. Confirm Free Space has at least 230 GiB.

    7. Confirm that the storage domain meets these etcd backend performance requirements, which you can measure by using the fio performance benchmarking tool.

    8. In the data center details, click the Clusters tab.

    9. Find the RHV cluster where you plan to install OpenShift Container Platform. Record the cluster name for use later on.

  3. Inspect the RHV host resources.

    1. In the RHV Administration Portal, click Compute > Clusters.

    2. Click the cluster where you plan to install OpenShift Container Platform.

    3. In the cluster details, click the Hosts tab.

    4. Inspect the hosts and confirm they have a combined total of at least 28 Logical CPU Cores available exclusively for the OpenShift Container Platform cluster.

    5. Record the number of available Logical CPU Cores for use later on.

    6. Confirm that these CPU cores are distributed so that each of the seven virtual machines created during installation can have four cores.

    7. Confirm that, all together, the hosts have 112 GiB of Max free Memory for scheduling new virtual machines distributed to meet the requirements for each of the following OpenShift Container Platform machines:

      • 16 GiB required for the bootstrap machine

      • 16 GiB required for each of the three control plane machines

      • 16 GiB for each of the three compute machines

    8. Record the amount of Max free Memory for scheduling new virtual machines for use later on.

  4. Verify that the virtual network for installing OpenShift Container Platform has access to the RHV Manager’s REST API. From a virtual machine on this network, use curl to reach the RHV Manager’s REST API:

    $ curl -k -u <username>@<profile>:<password> \ (1)
    https://<engine-fqdn>/ovirt-engine/api (2)
    1 For <username>, specify the user name of an RHV account with privileges to create and manage an OpenShift Container Platform cluster on RHV. For <profile>, specify the login profile, which you can get by going to the RHV Administration Portal login page and reviewing the Profile dropdown list. For <password>, specify the password for that user name.
    2 For <engine-fqdn>, specify the fully qualified domain name of the RHV environment.

    For example:

    $ curl -k -u ocpadmin@internal:pw123 \
    https://rhv-env.virtlab.example.com/ovirt-engine/api

Preparing the network environment on RHV

Configure two static IP addresses for the OpenShift Container Platform cluster and create DNS entries using these addresses.

Procedure
  1. Reserve two static IP addresses

    1. On the network where you plan to install OpenShift Container Platform, identify two static IP addresses that are outside the DHCP lease pool.

    2. Connect to a host on this network and verify that each of the IP addresses is not in use. For example, use Address Resolution Protocol (ARP) to check that none of the IP addresses have entries:

      $ arp 10.35.1.19
      Example output
      10.35.1.19 (10.35.1.19) -- no entry
    3. Reserve two static IP addresses following the standard practices for your network environment.

    4. Record these IP addresses for future reference.

  2. Create DNS entries for the OpenShift Container Platform REST API and apps domain names using this format:

    api.<cluster-name>.<base-domain>   <ip-address> (1)
    *.apps.<cluster-name>.<base-domain>   <ip-address> (2)
    1 For <cluster-name>, <base-domain>, and <ip-address>, specify the cluster name, base domain, and static IP address of your OpenShift Container Platform API.
    2 Specify the cluster name, base domain, and static IP address of your OpenShift Container Platform apps for Ingress and the load balancer.

    For example:

    api.my-cluster.virtlab.example.com	10.35.1.19
    *.apps.my-cluster.virtlab.example.com	10.35.1.20

Installing OpenShift Container Platform on RHV in insecure mode

By default, the installer creates a CA certificate, prompts you for confirmation, and stores the certificate to use during installation. You do not need to create or install one manually.

Although it is not recommended, you can override this functionality and install OpenShift Container Platform without verifying a certificate by installing OpenShift Container Platform on RHV in insecure mode.

Installing in insecure mode is not recommended, because it enables a potential attacker to perform a Man-in-the-Middle attack and capture sensitive credentials on the network.

Procedure
  1. Create a file named ~/.ovirt/ovirt-config.yaml.

  2. Add the following content to ovirt-config.yaml:

    ovirt_url: \https://ovirt.example.com/ovirt-engine/api
    ovirt_fqdn: ovirt.example.com
    ovirt_pem_url: ""
    ovirt_username: ocpadmin@internal
    ovirt_password: super-secret-password
    ovirt_insecure: true
  3. Run the installer.

Generating a key pair for cluster node SSH access

During an OpenShift Container Platform installation, you can provide an SSH public key to the installation program. The key is passed to the Red Hat Enterprise Linux CoreOS (RHCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys list for the core user on each node, which enables password-less authentication.

After the key is passed to the nodes, you can use the key pair to SSH in to the RHCOS nodes as the user core. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.

If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather command also requires the SSH public key to be in place on the cluster nodes.

Do not skip this procedure in production environments, where disaster recovery and debugging is required.

Procedure
  1. If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, create one. For example, on a computer that uses a Linux operating system, run the following command:

    $ ssh-keygen -t ed25519 -N '' -f <path>/<file_name> (1)
    1 Specify the path and file name, such as ~/.ssh/id_rsa, of the new SSH key. If you have an existing key pair, ensure your public key is in the your ~/.ssh directory.

    If you plan to install an OpenShift Container Platform cluster that uses FIPS Validated / Modules in Process cryptographic libraries on the x86_64 architecture, do not create a key that uses the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.

  2. View the public SSH key:

    $ cat <path>/<file_name>.pub

    For example, run the following to view the ~/.ssh/id_rsa.pub public key:

    $ cat ~/.ssh/id_rsa.pub
  3. Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the ./openshift-install gather command.

    On some distributions, default SSH private key identities such as ~/.ssh/id_rsa and ~/.ssh/id_dsa are managed automatically.

    1. If the ssh-agent process is not already running for your local user, start it as a background task:

      $ eval "$(ssh-agent -s)"
      Example output
      Agent pid 31874

      If your cluster is in FIPS mode, only use FIPS-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.

  4. Add your SSH private key to the ssh-agent:

    $ ssh-add <path>/<file_name> (1)
    1 Specify the path and file name for your SSH private key, such as ~/.ssh/id_rsa
    Example output
    Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
Next steps
  • When you install OpenShift Container Platform, provide the SSH public key to the installation program.

Obtaining the installation program

Before you install OpenShift Container Platform, download the installation file on a local computer.

Prerequisites
  • You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure
  1. Access the Infrastructure Provider page on the Red Hat OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.

  2. Select your infrastructure provider.

  3. Navigate to the page for your installation type, download the installation program for your operating system, and place the file in the directory where you will store the installation configuration files.

    The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.

    Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OpenShift Container Platform uninstallation procedures for your specific cloud provider.

  4. Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:

    $ tar xvf openshift-install-linux.tar.gz
  5. From the Pull Secret page on the Red Hat OpenShift Cluster Manager site, download your installation pull secret. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.

Creating the installation configuration file

You can customize the OpenShift Container Platform cluster you install on Red Hat Virtualization (RHV).

Prerequisites
  • Obtain the OpenShift Container Platform installation program and the pull secret for your cluster.

Procedure
  1. Create the install-config.yaml file.

    1. Change to the directory that contains the installation program and run the following command:

      $ ./openshift-install create install-config --dir=<installation_directory> (1)
      1 For <installation_directory>, specify the directory name to store the files that the installation program creates.

      Specify an empty directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.

    2. Respond to the installation program prompts.

      1. For SSH Public Key, select a password-less public key, such as ~/.ssh/id_rsa.pub. This key authenticates connections with the new OpenShift Container Platform cluster.

        For production OpenShift Container Platform clusters on which you want to perform installation debugging or disaster recovery, select an SSH key that your ssh-agent process uses.

      2. For Platform, select ovirt.

      3. For Enter oVirt’s API endpoint URL, enter the URL of the RHV API using this format:

        https://<engine-fqdn>/ovirt-engine/api (1)
        1 For <engine-fqdn>, specify the fully qualified domain name of the RHV environment.

        For example:

        $ curl -k -u ocpadmin@internal:pw123 \
        https://rhv-env.virtlab.example.com/ovirt-engine/api
      4. For Is the oVirt CA trusted locally?, enter Yes, because you have already set up a CA certificate. Otherwise, enter No.

      5. For oVirt’s CA bundle, if you entered Yes for the preceding question, copy the certificate content from /etc/pki/ca-trust/source/anchors/ca.pem and paste it here. Then, press Enter twice. Otherwise, if you entered No for the preceding question, this question does not appear.

      6. For oVirt engine username, enter the user name and profile of the RHV administrator using this format:

        <username>@<profile> (1)
        1 For <username>, specify the user name of an RHV administrator. For <profile>, specify the login profile, which you can get by going to the RHV Administration Portal login page and reviewing the Profile dropdown list. Together, the user name and profile should look similar to this example:
        ocpadmin@internal
      7. For oVirt engine password, enter the RHV admin password.

      8. For oVirt cluster, select the cluster for installing OpenShift Container Platform.

      9. For oVirt storage domain, select the storage domain for installing OpenShift Container Platform.

      10. For oVirt network, select a virtual network that has access to the RHV Manager REST API.

      11. For Internal API Virtual IP, enter the static IP address you set aside for the cluster’s REST API.

      12. For Ingress virtual IP, enter the static IP address you reserved for the wildcard apps domain.

      13. For Base Domain, enter the base domain of the OpenShift Container Platform cluster. If this cluster is exposed to the outside world, this must be a valid domain recognized by DNS infrastructure. For example, enter: virtlab.example.com

      14. For Cluster Name, enter the name of the cluster. For example, my-cluster. Use cluster name from the externally registered/resolvable DNS entries you created for the OpenShift Container Platform REST API and apps domain names. The installation program also gives this name to the cluster in the RHV environment.

      15. For Pull Secret, copy the pull secret from the pull-secret.txt file you downloaded earlier and paste it here. You can also get a copy of the same pull secret from the Pull Secret page on the Red Hat OpenShift Cluster Manager site.

  2. Modify the install-config.yaml file. You can find more information about the available parameters in the "Installation configuration parameters" section.

    If you have any intermediate CA certificates on the Manager, verify that the certificates appear in the ovirt-config.yaml file and the install-config.yaml file. If they do not appear, add them as follows:

    1. In the ~/.ovirt/ovirt-config.yaml file:

      [ovirt_ca_bundle]: |
           -----BEGIN CERTIFICATE-----
           <MY_TRUSTED_CA>
           -----END CERTIFICATE-----
           -----BEGIN CERTIFICATE-----
           <INTERMEDIATE_CA>
           -----END CERTIFICATE-----
    2. In the install-config.yaml file:

      [additionalTrustBundle]: |
           -----BEGIN CERTIFICATE-----
           <MY_TRUSTED_CA>
           -----END CERTIFICATE-----
           -----BEGIN CERTIFICATE-----
           <INTERMEDIATE_CA>
           -----END CERTIFICATE-----
  3. Back up the install-config.yaml file so that you can use it to install multiple clusters.

    The install-config.yaml file is consumed during the installation process. If you want to reuse the file, you must back it up now.

Example install-config.yaml files for Red Hat Virtualization (RHV)

You can customize the OpenShift Container Platform cluster the installation program creates by changing the parameters and parameter values in the install-config.yaml file.

The following examples are specific to installing OpenShift Container Platform on RHV.

install-config.yaml is located in <installation_directory>, which you specified when you ran the following command.

$ ./openshift-install create install-config --dir=<installation_directory>
  • These example files are provided for reference only. You must obtain your install-config.yaml file by using the installation program.

  • Changing the install-config.yaml file can increase the resources your cluster requires. Verify that your RHV environment has those additional resources. Otherwise, the installation or cluster will fail.

Example default install-config.yaml file

apiVersion: v1
baseDomain: example.com
compute:
- architecture: amd64
  hyperthreading: Enabled
  name: worker
  platform: {}
  replicas: 3
controlPlane:
  architecture: amd64
  hyperthreading: Enabled
  name: master
  platform: {}
  replicas: 3
metadata:
  creationTimestamp: null
  name: my-cluster
networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  machineNetwork:
  - cidr: 10.0.0.0/16
  networkType: OpenShiftSDN
  serviceNetwork:
  - 172.30.0.0/16
platform:
  ovirt:
    api_vip: 10.46.8.230
    ingress_vip: 192.168.1.5
    ovirt_cluster_id: 68833f9f-e89c-4891-b768-e2ba0815b76b
    ovirt_storage_domain_id: ed7b0f4e-0e96-492a-8fff-279213ee1468
    ovirt_network_name: ovirtmgmt
    vnicProfileID: 3fa86930-0be5-4052-b667-b79f0a729692
publish: External
pullSecret: '{"auths": ...}'
sshKey: ssh-ed12345 AAAA...

Example minimal install-config.yaml file

apiVersion: v1
baseDomain: example.com
metadata:
  name: test-cluster
platform:
  ovirt:
    api_vip: 10.46.8.230
    ingress_vip: 10.46.8.232
    ovirt_cluster_id: 68833f9f-e89c-4891-b768-e2ba0815b76b
    ovirt_storage_domain_id: ed7b0f4e-0e96-492a-8fff-279213ee1468
    ovirt_network_name: ovirtmgmt
    vnicProfileID: 3fa86930-0be5-4052-b667-b79f0a729692
pullSecret: '{"auths": ...}'
sshKey: ssh-ed12345 AAAA...

Example Custom machine pools in an install-config.yaml file

apiVersion: v1
baseDomain: example.com
controlPlane:
  name: master
  platform:
    ovirt:
      cpu:
        cores: 4
        sockets: 2
      memoryMB: 65536
      osDisk:
        sizeGB: 100
      vmType: server
  replicas: 3
compute:
- name: worker
  platform:
    ovirt:
      cpu:
        cores: 4
        sockets: 4
      memoryMB: 65536
      osDisk:
        sizeGB: 200
      vmType: server
  replicas: 5
metadata:
  name: test-cluster
platform:
  ovirt:
    api_vip: 10.46.8.230
    ingress_vip: 10.46.8.232
    ovirt_cluster_id: 68833f9f-e89c-4891-b768-e2ba0815b76b
    ovirt_storage_domain_id: ed7b0f4e-0e96-492a-8fff-279213ee1468
    ovirt_network_name: ovirtmgmt
    vnicProfileID: 3fa86930-0be5-4052-b667-b79f0a729692
pullSecret: '{"auths": ...}'
sshKey: ssh-ed25519 AAAA...

Example non-enforcing affinity group

It is recommended to add a non-enforcing affinity group to distribute the control plane and workers, if possible, to use as much of the cluster as possible.

platform:
  ovirt:
    affinityGroups:
    - description: AffinityGroup to place each compute machine on a separate host
      enforcing: true
      name: compute
      priority: 3
    - description: AffinityGroup to place each control plane machine on a separate host
      enforcing: true
      name: controlplane
      priority: 5
    - description: AffinityGroup to place worker nodes and control plane nodes on separate hosts
      enforcing: false
      name: openshift
      priority: 5
compute:
- architecture: amd64
  hyperthreading: Enabled
  name: worker
  platform:
    ovirt:
      affinityGroupsNames:
      - compute
      - openshift
  replicas: 3
controlPlane:
  architecture: amd64
  hyperthreading: Enabled
  name: master
  platform:
    ovirt:
      affinityGroupsNames:
      - controlplane
      - openshift
  replicas: 3

Example removing all affinity groups for a non-production lab setup

For non-production lab setups, you must remove all affinity groups to concentrate the OpenShift Container Platform cluster on the few hosts you have.

platform:
  ovirt:
    affinityGroups: []
compute:
- architecture: amd64
  hyperthreading: Enabled
  name: worker
  platform:
    ovirt:
      affinityGroupsNames: []
  replicas: 3
controlPlane:
  architecture: amd64
  hyperthreading: Enabled
  name: master
  platform:
    ovirt:
      affinityGroupsNames: []
  replicas: 3

Installation configuration parameters

Before you deploy an OpenShift Container Platform cluster, you provide parameter values to describe your account on the cloud platform that hosts your cluster and optionally customize your cluster’s platform. When you create the install-config.yaml installation configuration file, you provide values for the required parameters through the command line. If you customize your cluster, you can modify the install-config.yaml file to provide more details about the platform.

After installation, you cannot modify these parameters in the install-config.yaml file.

The openshift-install command does not validate field names for