Hi Paolo, Thanks for this KIP, it solves for a real problem that we at Aiven have also found ourselves needing a solution for.
Just to note first that this topic has been discussed before on the mail thread, see "KRaft controller disaster recovery", here: https://lists.apache.org/thread/84hbwwz46401vf81355v03ypyzkph32f. On Aiven, we have built custom tooling to handle such disaster recovery cases (or rather, best-effort restoring availability, as this is a data loss scenario). The tooling we have built works like this: - Operator runs a tool to identify the longest log copy available. As both brokers and controllers replicate the log, it may be that a broker holds the most extensive copy of the log. This works by inspecting the raft log on disk on each surviving node in the cluster and identifying the one with the highest log end offset. - The operator then invokes another tool on the chosen node that manually modifies the log on disk to reduce the voter set to only that controller, so that it gains quorum on its own. - From this we can start all surviving and participants of the cluster up again, and our normal automations will scale the voter set up to 3 or 5 again. Let me know if it is of interest, and I can do what I can to share more of this custom tooling. We could likely open source it in some form. BR, Anton Den mån 18 maj 2026 kl 15:55 skrev Paolo Patierno <[email protected] >: > Hi all, > I would like to start a discussion on KIP-1347 > < > https://cwiki.apache.org/confluence/display/KAFKA/KIP-1347%3A+Overriding+voter+set+on+storage+formatting > > > which > is about allowing the override of the voter set through the storage > formatting tool to recover a disaster scenario where the KRaft quorum can't > be formed anymore. This KIP aims to fix KAFKA-20427 > <https://issues.apache.org/jira/browse/KAFKA-20427>. > Any feedback is very welcome. > > Thanks, > Paolo. > > -- > Paolo Patierno > > *Senior Principal Software Engineer @ IBM**CNCF Ambassador* > > Twitter : @ppatierno <http://twitter.com/ppatierno> > Linkedin : paolopatierno <http://it.linkedin.com/in/paolopatierno> > GitHub : ppatierno <https://github.com/ppatierno> >
