Feature Overview

The Agent-based Installer (ABI) will be updated to support the installation of OpenShift Container Platform (OCP) 4.22 using either Red Hat CoreOS (RHCOS) 9 or RHCOS 10 as the base operating system. This capability ensures that Cluster Administrators can deploy OCP 4.22 in environments requiring the latest operating system stream, maintaining compatibility with the dual-stream release strategy for RHCOS.

Goals

• Primary Goal: Enable the Agent-based Installer to successfully deploy an OpenShift Container Platform 4.22 cluster with nodes provisioned using the RHCOS 10 base image.
• Anticipated Primary User: Cluster Administrator.
• Expanded Functionality: This feature expands the installer's current compatibility matrix by adding support for a new, major version of Red Hat CoreOS.
• Operational Goals:
  • Ensure that clusters can be installed with RHCOS 9.x or RHCOS 10.x as the base image.
  • Validate that clusters can successfully operate with varying versions of RHCOS (9.x and 10.x) across different MachineConfigPools of the same cluster.
  • Maintain the existing control mechanisms used by Red Hat to determine which Red Hat Enterprise Linux (RHEL) minors are compatible with specific RHCOS versions.

Requirements

Functional Requirements

1. The Agent-based Installer must correctly identify and present the available RHCOS 9 and RHCOS 10 images for OCP 4.22 deployment.
2. The installation process must successfully provision OCP 4.22 nodes using the selected RHCOS 10 image.
3. The deployed OCP cluster must remain fully functional and supported when utilizing a mix of RHCOS 9 and RHCOS 10 nodes.
4. All installer validation checks must pass when installing with RHCOS 10.

Non-Functional Requirements

All non-functional requirements (including security, reliability, performance, maintainability, scalability, and usability) must be identical to the standards currently applied to RHCOS 9 support within the Agent-based Installer. No degradation or change in non-functional performance is acceptable.

User Scenarios

• As a Cluster Administrator, I want to install OpenShift Container Platform 4.22 using the Agent-based Installer so that I can immediately deploy my cluster on the newest certified operating system stream, RHCOS 10.
• As a Cluster Administrator, I want to use a single OCP 4.22 installation media to deploy a cluster with either RHCOS 9 or RHCOS 10 so that I can maintain flexibility based on my infrastructure's specific requirements or hardware compatibility needs.
• As a Cluster Administrator, I want to add new machine pools using the RHCOS 10 base image to an existing OCP 4.22 cluster that was initially deployed with RHCOS 9 so that I can leverage the latest operating system features for new workloads without impacting existing nodes.

Out of Scope

Links

• Master JIRA Issue: https://issues.redhat.com/browse/OCPSTRAT-1150