1. Proposed title of this feature request

Machine Config Pool upgrade rollback 
2. What is the nature and description of the request?

In an upgrade scenario, it would be a great addition to add the possibility to rollback a certain MCP's nodes to the previous Z or Y release.
3. Why does the customer need this? (List the business requirements here)

If after an upgrade is performed, some of the applications start running into some issues specific to the new OCP version, the customer could rollback the workers and keep the control plane updated till the issues are fixed.
4. List any affected packages or components.

MCO