Summary & Value

The downstream build process only supports one in-flight Z-stream release per Y-stream release. This presents challenges when faced with the unpredictable need for CVE-only z-stream releases. When developing a z-stream, we ship the previous z-stream and immediately open the build for changes unless there is a current outstanding CVE to address. Once changes are submitted to a z-stream, QE needs to run through a full regression before we ship that Z-stream release. This means we can no longer quickly turn around base-image-only CVE fixes to meet our 5 day deadline.

The ability to revert all changes that have entered a Z-stream from the time it was opened for changes at the midstream level would allow us to revert and convert a Z-stream release into a CVE-only base-images-only release, then replay changes back onto the midstream at a later date. This would simplify the process of meeting CVE deadlines without overburdening QE with the need for quick-turnaround regression tests.

Acceptance Criteria

• Feasibility of our "Z-Stream Time Machine" feature evaluated
• Basic architecture identified with PoC
• FeatureSpec written and presented to Architecture call if deemed feasible