[KAFKA-8509] Add downgrade system tests

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: system tests
• Assignee: Jason Gustafson
• Reporter: Jason Gustafson
• Created: 07/Jun/19 18:35
• Updated: 22/Nov/19 18:09
• Resolved: 22/Nov/19 18:09

Description

We've been bitten a few times by downgrade incompatibilities. It should be straightforward to adapt our current upgrade system tests to support downgrades as well. The basic procedure should be: 

1. Roll the cluster with the updated binary, keep IBP on old version
2. Verify produce/consume
3. Roll the cluster with the old binary, keep IBP the same.
4. Verify produce/consume

Issue Links

• links to: GitHub Pull Request #7724