Prerequisites

The following items are required to install an OpenShift Container Platform cluster on a RHV environment.

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.

  • 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

Networking requirements for user-provisioned infrastructure

All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require networking to be configured in initramfs during boot to fetch their Ignition config files.

During the initial boot, the machines require an IP address configuration that is set either through a DHCP server or statically by providing the required boot options. After a network connection is established, the machines download their Ignition config files from an HTTP or HTTPS server. The Ignition config files are then used to set the exact state of each machine. The Machine Config Operator completes more changes to the machines, such as the application of new certificates or keys, after installation.

It is recommended to use a DHCP server for long-term management of the cluster machines. Ensure that the DHCP server is configured to provide persistent IP addresses, DNS server information, and hostnames to the cluster machines.

If a DHCP service is not available for your user-provisioned infrastructure, you can instead provide the IP networking configuration and the address of the DNS server to the nodes at RHCOS install time. These can be passed as boot arguments if you are installing from an ISO image. See the Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines section for more information about static IP provisioning and advanced networking options.

The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.

Firewall

Configure your firewall so your cluster has access to required sites.

See also:

Load balancers

Configure one or preferably two layer-4 load balancers:

  • Provide load balancing for ports 6443 and 22623 on the control plane and bootstrap machines. Port 6443 provides access to the Kubernetes API server and must be reachable both internally and externally. Port 22623 must be accessible to nodes within the cluster.

  • Provide load balancing for port 443 and 80 for machines that run the Ingress router, which are usually compute nodes in the default configuration. Both ports must be accessible from within and outside the cluster.

DNS

Configure infrastructure-provided DNS to allow the correct resolution of the main components and services. If you use only one load balancer, these DNS records can point to the same IP address.

  • Create DNS records for api.<cluster_name>.<base_domain> (internal and external resolution) and api-int.<cluster_name>.<base_domain> (internal resolution) that point to the load balancer for the control plane machines.

  • Create a DNS record for *.apps.<cluster_name>.<base_domain> that points to the load balancer for the Ingress router. For example, ports 443 and 80 of the compute machines.

Setting the cluster node hostnames through DHCP

On Red Hat Enterprise Linux CoreOS (RHCOS) machines, the hostname is set through NetworkManager. By default, the machines obtain their hostname through DHCP. If the hostname is not provided by DHCP, it is obtained through a reverse DNS lookup. Reverse DNS lookup occurs after the network has been initialized on a node and can take time to resolve. Other system services can start prior to this and detect the hostname as localhost or similar. You can avoid this by using DHCP to provide the hostname for each cluster node.

Additionally, setting the hostnames through DHCP can bypass any manual DNS record name configuration errors in environments that have a DNS split-horizon implementation.

Network connectivity requirements

You must configure the network connectivity between machines to allow OpenShift Container Platform cluster components to communicate. Each machine must be able to resolve the hostnames of all other machines in the cluster.

This section provides details about the ports that are required.

In connected OpenShift Container Platform environments, all nodes are required to have internet access to pull images for platform containers and provide telemetry data to Red Hat.

Table 1. Ports used for all-machine to all-machine communications
Protocol Port Description

ICMP

N/A

Network reachability tests

TCP

1936

Metrics

9000-9999

Host level services, including the node exporter on ports 9100-9101 and the Cluster Version Operator on port 9099.

10250-10259

The default ports that Kubernetes reserves

10256

openshift-sdn

UDP

4789

VXLAN and Geneve

6081

VXLAN and Geneve

9000-9999

Host level services, including the node exporter on ports 9100-9101.

TCP/UDP

30000-32767

Kubernetes node port

Table 2. Ports used for all-machine to control plane communications
Protocol Port Description

TCP

6443

Kubernetes API

Table 3. Ports used for control plane machine to control plane machine communications
Protocol Port Description

TCP

2379-2380

etcd server and peer ports

NTP configuration for user-provisioned infrastructure

OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.

If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

Setting up the installation machine

To run the binary openshift-install installation program and Ansible scripts, set up the RHV Manager or an Red Hat Enterprise Linux (RHEL) computer with network access to the RHV environment and the REST API on the Manager.

Procedure
  1. Update or install Python3 and Ansible. For example:

    # dnf update python3 ansible
  2. Install the python3-ovirt-engine-sdk4 package to get the Python Software Development Kit.

  3. Install the ovirt.image-template Ansible role. On the RHV Manager and other Red Hat Enterprise Linux (RHEL) machines, this role is distributed as the ovirt-ansible-image-template package. For example, enter:

    # dnf install ovirt-ansible-image-template
  4. Install the ovirt.vm-infra Ansible role. On the RHV Manager and other RHEL machines, this role is distributed as the ovirt-ansible-vm-infra package.

    # dnf install ovirt-ansible-vm-infra
  5. Create an environment variable and assign an absolute or relative path to it. For example, enter:

    $ export ASSETS_DIR=./wrk

    The installation program uses this variable to create a directory where it saves important installation-related files. Later, the installation process reuses this variable to locate those asset files. Avoid deleting this assets directory; it is required for uninstalling the cluster.

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.

You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.

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.

Downloading the Ansible playbooks

Download the Ansible playbooks for installing OpenShift Container Platform version 4.8 on RHV.

Procedure
  1. On your installation machine, run the following commands:

    $ mkdir playbooks
    $ cd playbooks
    $ curl -s -L -X GET https://api.github.com/repos/openshift/installer/contents/upi/ovirt?ref=release-4.8  |
    grep 'download_url.*\.yml' |
    awk '{ print $2 }' | sed -r 's/("|",)//g' |
    xargs -n 1 curl -O
Next steps
  • After you download these Ansible playbooks, you must also create the environment variable for the assets directory and customize the inventory.yml file before you create an installation configuration file by running the installation program.

The inventory.yml file

You use the inventory.yml file to define and create elements of the OpenShift Container Platform cluster you are installing. This includes elements such as the Red Hat Enterprise Linux CoreOS (RHCOS) image, virtual machine templates, bootstrap machine, control plane nodes, and worker nodes. You also use inventory.yml to destroy the cluster.

The following inventory.yml example shows you the parameters and their default values. The quantities and numbers in these default values meet the requirements for running a production OpenShift Container Platform cluster in a RHV environment.

Example inventory.yml file
---
all:
  vars:

    ovirt_cluster: "Default"
    ocp:
      assets_dir: "{{ lookup('env', 'ASSETS_DIR') }}"
      ovirt_config_path: "{{ lookup('env', 'HOME') }}/.ovirt/ovirt-config.yaml"

    # ---
    # {op-system} section
    # ---
    rhcos:
      image_url: "https://mirror.openshift.com/pub/openshift-v4/dependencies/rhcos/4.8/latest/rhcos-openstack.x86_64.qcow2.gz"
      local_cmp_image_path: "/tmp/rhcos.qcow2.gz"
      local_image_path: "/tmp/rhcos.qcow2"

    # ---
    # Profiles section
    # ---
    control_plane:
      cluster: "{{ ovirt_cluster }}"
      memory: 16GiB
      sockets: 4
      cores: 1
      template: rhcos_tpl
      operating_system: "rhcos_x64"
      type: high_performance
      graphical_console:
        headless_mode: false
        protocol:
        - spice
        - vnc
      disks:
      - size: 120GiB
        name: os
        interface: virtio_scsi
        storage_domain: depot_nvme
      nics:
      - name: nic1
        network: lab
        profile: lab

    compute:
      cluster: "{{ ovirt_cluster }}"
      memory: 16GiB
      sockets: 4
      cores: 1
      template: worker_rhcos_tpl
      operating_system: "rhcos_x64"
      type: high_performance
      graphical_console:
        headless_mode: false
        protocol:
        - spice
        - vnc
      disks:
      - size: 120GiB
        name: os
        interface: virtio_scsi
        storage_domain: depot_nvme
      nics:
      - name: nic1
        network: lab
        profile: lab

    # ---
    # Virtual machines section
    # ---
    vms:
    - name: "{{ metadata.infraID }}-bootstrap"
      ocp_type: bootstrap
      profile: "{{ control_plane }}"
      type: server
    - name: "{{ metadata.infraID }}-master0"
      ocp_type: master
      profile: "{{ control_plane }}"
    - name: "{{ metadata.infraID }}-master1"
      ocp_type: master
      profile: "{{ control_plane }}"
    - name: "{{ metadata.infraID }}-master2"
      ocp_type: master
      profile: "{{ control_plane }}"
    - name: "{{ metadata.infraID }}-worker0"
      ocp_type: worker
      profile: "{{ compute }}"
    - name: "{{ metadata.infraID }}-worker1"
      ocp_type: worker
      profile: "{{ compute }}"
    - name: "{{ metadata.infraID }}-worker2"
      ocp_type: worker
      profile: "{{ compute }}"

Enter values for parameters whose descriptions begin with "Enter." Otherwise, you can use the default value or replace it with a new value.

General section
  • ovirt_cluster: Enter the name of an existing RHV cluster in which to install the OpenShift Container Platform cluster.

  • ocp.assets_dir: The path of a directory the openshift-install installation program creates to store the files that it generates.

  • ocp.ovirt_config_path: The path of the ovirt-config.yaml file the installation program generates, for example, ./wrk/install-config.yaml. This file contains the credentials required to interact with the REST API of the Manager.

Red Hat Enterprise Linux CoreOS (RHCOS) section
  • image_url: Enter the URL of the RHCOS image you specified for download.

  • local_cmp_image_path: The path of a local download directory for the compressed RHCOS image.

  • local_image_path: The path of a local directory for the extracted RHCOS image.

Profiles section

This section consists of two profiles:

  • control_plane: The prof