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https://issues.apache.org/jira/browse/CAMEL-24545?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18108924#comment-18108924
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mustafa kamal commented on CAMEL-24545:
---------------------------------------
A PR with the fix https://github.com/apache/camel/pull/25842
> Camel Shutdown Locked State With ZookeeprCluster Service
> --------------------------------------------------------
>
> Key: CAMEL-24545
> URL: https://issues.apache.org/jira/browse/CAMEL-24545
> Project: Camel
> Issue Type: Bug
> Components: camel-zookeeper, camel-zookeeper-master
> Affects Versions: 4.22.1, 4.18.5
> Environment: One ZK instance and one camel instance running
> ZooKeeperClusterService you need to use the main branch or any fix branch as
> this PR didn't span into a released version.
> Reporter: mustafa kamal
> Priority: Major
> Labels: Deadlock
> Attachments: dump.txt
>
>
> During shutdown, Camel's ClusteredRoutePolicy.onRemove and the Curator
> leader selector thread both run concurrently because some routes keep the
> shutdown window open long enough. These two threads acquire the same two
> locks in opposite order, causing a classic deadlock that permanently hangs
> the JVM.
> You can check the attached Thread Dump to see the technical level of the
> issue more.
>
> Possible fix is to surround `fireLeadershipChangedEvent((CamelClusterMember)
> null);` line 154 in `ZooKeeperClusterView` class, with `if
> (!isStoppingOrStopped())` that will solve the dead lock issue
> Another issue it solved the unnecessary firing of the Leadership Change event
> because on stopping/shutting down the view all the registered listeners will
> be removed so any reaction they need to do should be before stopping the view
> because stopping the view is not as the same as Losing the Leadership Lock so
> that's more of an enhancement than breaking functionality.
>
> To reproduce the issue run the application wait until it's the Leader by
> acquiring the lock in ZK then shutting down the application, not all routes
> will produce the issue some routes have a long enough shutdown windows that
> allows the Dead Lock to happen
>
> This issue is related to the PR [https://github.com/apache/camel/pull/25611]
> for ticket https://issues.apache.org/jira/projects/CAMEL/issues/CAMEL-24457
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