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Installing a cluster on RHV with customizations

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 4.9, 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 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.

Requirements for the RHV environment

To install and run an OpenShift Container Platform version 4.9 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 4.9.

    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 Compute → Data 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 (1)
ovirt_fqdn: ovirt.example.com (2)
ovirt_pem_url: ""
ovirt_username: admin@internal
ovirt_password: super-secret-password (3)
ovirt_insecure: true