Thanks for this KIP, Jose - Could you please explain the following about backward compatibility. If a leader has been elected unclean. And we decide to roll the cluster back when the leader is in the middle of recovery, leader will simply not be able to recover when we roll back because it will lose its local copy of the unclean flag. Even if the controller sends another `LISR` to the leader, it will ignore the flag. So, the leader will not be able to carry on its recovery workflow. It will treat the situation as if it was not elected unclean and carry on with expanding ISR.- ``` When thinking about backward compatibility it is important to note that if the "is unclean" field is true then the ISR is guarantee to have a size of 1. The topic partition leader will not increase the ISR until it has recovered from the unclean leader election and has set the "is unclean" field to false. ```
On Wed, Jan 19, 2022 at 4:52 PM José Armando García Sancio <jsan...@confluent.io.invalid> wrote: > > Hi all, > > I made the following changes to the KIP: > https://cwiki.apache.org/confluence/pages/diffpagesbyversion.action?pageId=173082256&selectedPageVersions=12&selectedPageVersions=11 > > Some of the highlights are: > 1. Changed the field from IsUnclean to IsLeaderRecovering > 2. Added a few more sentences explaining why this KIP is backward > compatible and the interaction between the controller and the > partition leaders when they are in different software versions. > > Thanks > -José -- Best Regards, Raman Verma
