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https://issues.apache.org/jira/browse/CURATOR-652?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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shixiaoxiao resolved CURATOR-652.
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Resolution: Fixed
> double-leader
> -------------
>
> Key: CURATOR-652
> URL: https://issues.apache.org/jira/browse/CURATOR-652
> Project: Apache Curator
> Issue Type: Bug
> Affects Versions: 5.1.0, 5.2.0, 5.3.0
> Reporter: shixiaoxiao
> Assignee: Jordan Zimmerman
> Priority: Critical
> Fix For: awaiting-response
>
>
> When I use the LeaderLatch to select leader, there is a double-leader
> phenomenon.
> The timeline is as follows：
> 1. The zk cluster switch leader node bescause of zxid overflow. The cluster
> is unavailable to the outside world
> 2. A client(not leader befor zxid overflow) and B client(is leader before
> zxid overflow) enter the suspend state, B client set its leader status to
> false
> 3. The zk cluster complete the leader node election and the cluster back to
> normal
> 4. A client enter the reconnect state and call the reset function, set its
> leader status to false.
> 5. B client enter the reconnect state, call the reset function. set its
> leader status to false. Delete its old path.
> 6. A client receive preNodeDeleteEvent. Then getChildren from zkServer. Find
> itself is the smallest number and set itself as a leader.
> 7. B client create a new temporary node and then getChildren from zkServer.
> Find itself not the node with the smallest serial number and listen to the
> previous node delete event.
> 8. A client delete its old path.
> 9. B client receive the preNodeDeleteEvent. then getchildren from zkServer.
> Find itself is the smallest sequence number and then set itself as a leader
> 10. A client create a new temporary node and then getChildren from zkServer.
> Find itself not the node with the smallest serial number and listen to the
> previous node delete event. but it doesn't set itself as a non-leader state.
> because of the sixth step operation, A still is leader state now.
> 11. now A client and B client are the leader at the same time
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