[
https://issues.apache.org/jira/browse/KAFKA-5813?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Ray Chiang updated KAFKA-5813:
------------------------------
Component/s: zkclient
replication
> Unexpected unclean leader election due to leader/controller's unusual event
> handling order
> -------------------------------------------------------------------------------------------
>
> Key: KAFKA-5813
> URL: https://issues.apache.org/jira/browse/KAFKA-5813
> Project: Kafka
> Issue Type: Improvement
> Components: replication, zkclient
> Affects Versions: 0.10.2.1
> Reporter: Allen Wang
> Priority: Minor
>
> We experienced an unexpected unclean leader election after network glitch
> happened on the leader of partition. We have replication factor 2.
> Here is the sequence of event gathered from various logs:
> 1. ZK session timeout happens for leader of partition
> 2. New ZK session is established for leader
> 3. Leader removes the follower from ISR (which might be caused by replication
> delay due to the network problem) and updates the ISR in ZK
> 4. Controller processes the BrokerChangeListener event happened at step 1
> where the leader seems to be offline
> 5. Because the ISR in ZK is already updated by leader to remove the follower,
> controller makes an unclean leader election
> 6. Controller processes the second BrokerChangeListener event happened at
> step 2 to mark the broker online again
> It seems to me that step 4 happens too late. If it happens right after step
> 1, it will be a clean leader election and hopefully the producer will
> immediately switch to the new leader, thus avoiding consumer offset reset.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
