mynameborat opened a new pull request #1484: URL: https://github.com/apache/samza/pull/1484
**Description**: During rolling upgrades, the current debounce timer gets extended every time when there is a quorum change notification. As a result, processors that were upgraded earlier in the deployment window remain unavailable waiting for work assignment. In some scenarios, this cause processors to be unavailable for 20 minutes or so depending on the size of the quorum and the debounce time configuration. Refer to [SAMZA-2633](https://issues.apache.org/jira/browse/SAMZA-2633) for more information. **Changes**: - Optimize the leader workflow to skip rebalance if there is no changes to work assignment - Make processors start with most recent agreed job model on startup - Leader persists the active job model version in ZK to enable change [2] **Tests**: - Added unit tests to `ZkJobCoordinator` - Validated the rolling upgrade behavior with quorum size = 8, 24 and 32 with debounce time = upgrade time with various upgrade concurrency (25%, 10%, 75%, 100%) **API Changes**: None **Upgrade Instructions**: None **Usage Instructions**: None -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
