[KAFKA-5074] Transition to OnlinePartition without preferred leader in ISR fails

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.9.0.0
• Component/s: controller
• Assignee: Unassigned
• Reporter: Dustin Cote
• Created: 14/Apr/17 18:35
• Updated: 13/May/22 15:20

Description

Running 0.9.0.0, the controller can get into a state where it no longer is able to elect a leader for an Offline partition. It's unclear how this state is first achieved but in the steady state, this happens:
-There are partitions with a leader of -1
-The Controller repeatedly attempts a preferred leader election for these partitions
-The preferred leader election fails because the only replica in the ISR is not the preferred leader

The log cycle looks like this:

[2017-04-12 18:00:18,891] INFO [Controller 8]: Starting preferred replica leader election for partitions topic,1
[2017-04-12 18:00:18,891] INFO [Partition state machine on Controller 8]: Invoking state change to OnlinePartition for partitions topic,1
[2017-04-12 18:00:18,892] INFO [PreferredReplicaPartitionLeaderSelector]: Current leader -1 for partition [topic,1] is not the preferred replica. Trigerring preferred replica leader election (kafka.controller.PreferredReplicaPartitionLeaderSelector)
[2017-04-12 18:00:18,893] WARN [Controller 8]: Partition [topic,1] failed to complete preferred replica leader election. Leader is -1 (kafka.controller.KafkaController)

It's not clear if this would happen on versions later that 0.9.0.0.