kafka-jira mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jun Rao (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (KAFKA-1120) Controller could miss a broker state change
Date Fri, 07 Jul 2017 20:27:00 GMT

    [ https://issues.apache.org/jira/browse/KAFKA-1120?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16078619#comment-16078619
] 

Jun Rao commented on KAFKA-1120:
--------------------------------

[~wushujames], it seems that problem that you reproduced should have been fixed by https://issues.apache.org/jira/browse/KAFKA-5028.
In that jira, there will be only a single thread processing any broker change and controlled
shutdown request. So, they won't interleave. 

> Controller could miss a broker state change 
> --------------------------------------------
>
>                 Key: KAFKA-1120
>                 URL: https://issues.apache.org/jira/browse/KAFKA-1120
>             Project: Kafka
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 0.8.1
>            Reporter: Jun Rao
>              Labels: reliability
>
> When the controller is in the middle of processing a task (e.g., preferred leader election,
broker change), it holds a controller lock. During this time, a broker could have de-registered
and re-registered itself in ZK. After the controller finishes processing the current task,
it will start processing the logic in the broker change listener. However, it will see no
broker change and therefore won't do anything to the restarted broker. This broker will be
in a weird state since the controller doesn't inform it to become the leader of any partition.
Yet, the cached metadata in other brokers could still list that broker as the leader for some
partitions. Client requests routed to that broker will then get a TopicOrPartitionNotExistException.
This broker will continue to be in this bad state until it's restarted again.



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Mime
View raw message