Feature Overview

In 4.17 we introduced support for 4/5-node control planes:

https://docs.redhat.com/en/documentation/openshift_container_platform/4.18/html-single/scalability_and_performance/index#etcd-node-scaling_recommended-etcd-practices 

Before this we have been advising to scale up and then down from instructions in the article How to replace all master nodes in OpenShift Container Platform 4: 

https://access.redhat.com/articles/6270901 

The process in the article isn't covered in our CI tests and while is expected to work we must formalize this use case with the 4/5-node control planes feature introduced in 4.17. 

Goals 

• Validate and review the instructions in the article on OpenShift 4.17 onwards.
• Add reviewed instructions to the downstream documentation for the OpenShift Control Plane.

Backport to 4.17