Overview

Update the OpenShift Container Platform 4.19 documentation to introduce Technology Preview support for the Cluster API (CAPI) on bare metal clusters, using the Metal3 CAPI provider. This feature enables administrators to manage compute nodes and machine sets as an alternative to the Machine API (MAPI), with the long-term goal of replacing MAPI. The documentation updates should:

• Announce the feature in the OpenShift 4.19 Release Notes under "Technology Preview Features," highlighting CAPI’s role as an alternative node management mechanism for bare metal clusters.
• Expand "Chapter 12. Managing Machines with the Cluster API" with a new section detailing prerequisites, steps to enable CAPI for bare metal (e.g., enabling TechPreviewNoUpgrade, configuring Metal3 provider), and limitations (e.g., worker node management only, no MAPI-to-CAPI migration).
• Add a brief note in the "Installing a Cluster on Bare Metal" section to inform users of the CAPI option during bare metal IPI or UPI planning, linking to the CAPI chapter and release notes.
• Optionally, include a reference in "Chapter 4. Technology Previews" for completeness.

Scope

• Document the feature’s availability, configuration, and limitations for bare metal IPI and UPI clusters.
• Highlight that CAPI is a step toward replacing MAPI, aligning with upstream Kubernetes standards.
• Ensure consistency with existing CAPI documentation for AWS/GCP (e.g., Chapter 12).
• Release notes shold include a clear entry for CAPI bare metal support with links to detailed guidance.