Gabriella Lotz has posted comments on this change. ( http://gerrit.cloudera.org:8080/24476 )
Change subject: KUDU-3767 Add global leader awareness to auto leader rebalancer (Part 2) ...................................................................... Patch Set 5: (2 comments) http://gerrit.cloudera.org:8080/#/c/24476/3/src/kudu/master/auto_leader_rebalancer.cc File src/kudu/master/auto_leader_rebalancer.cc: http://gerrit.cloudera.org:8080/#/c/24476/3/src/kudu/master/auto_leader_rebalancer.cc@491 PS3, Line 491: // A leader is only ever handed to a tserver that already hosts a follower > For the example above, I'm not sure how those two factors can prevent endle Yes, I traced it through. ceil_avg = ceil(12/4) = 3, so TS0/TS1/TS2 (at 4) do look overloaded. But a leader can only be handed to a tserver that already hosts a follower of that tablet, and the only candidates are the other two of TS0/TS1/TS2, which are also at 4 (not below the ceiling), so they're rejected. TS3 is below the ceiling but hosts no replica, so it's never a follower and can't receive leadership. So no tablet has a valid destination and the pass makes no moves. Here it's the replica rebalancer that schedules moves (to populate TS3), the leader rebalancer doesn't. http://gerrit.cloudera.org:8080/#/c/24476/4/src/kudu/master/auto_leader_rebalancer.cc File src/kudu/master/auto_leader_rebalancer.cc: http://gerrit.cloudera.org:8080/#/c/24476/4/src/kudu/master/auto_leader_rebalancer.cc@807 PS4, Line 807: // > Do you think it is possible that we end up with non-zero per-table-moves al Good point, I think that's possible in a cluster with constant per-table churn. I've got a separate ticket for the leader rebalancer TODOs (metrics included), so I've added a TODO here to emit a metric when the global pass is skipped, and I'll cover it there. -- To view, visit http://gerrit.cloudera.org:8080/24476 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I5d44761f6444ca1d1bf4fcee405d65d029e41980 Gerrit-Change-Number: 24476 Gerrit-PatchSet: 5 Gerrit-Owner: Gabriella Lotz <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Ashwani Raina <[email protected]> Gerrit-Reviewer: Gabriella Lotz <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Reviewer: Marton Greber <[email protected]> Gerrit-Reviewer: Zoltan Chovan <[email protected]> Gerrit-Comment-Date: Thu, 09 Jul 2026 11:22:15 +0000 Gerrit-HasComments: Yes
