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https://issues.apache.org/jira/browse/ZOOKEEPER-2172?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexander Shraer updated ZOOKEEPER-2172:
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Attachment: ZOOKEPER-2172-05.patch
Thanks!
I made a few more changes:
- starting the new server with only itself and the leader in the inittial
config, so we can know that its config was really updated after reconfig
- changed the Learner.java logic a bit, to match what was there before ZK-107
(see revision history). Also I noticed that if majorChange = true we often skip
important logic when throwing an exception, so I moved the exception part to
the end of each code block.
Can another committer take a look before we commit ? [~cnauroth] [~rgs] [~fpj]
> Cluster crashes when reconfig a new node as a participant
> ---------------------------------------------------------
>
> Key: ZOOKEEPER-2172
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2172
> Project: ZooKeeper
> Issue Type: Bug
> Components: leaderElection, quorum, server
> Affects Versions: 3.5.0
> Environment: Ubuntu 12.04 + java 7
> Reporter: Ziyou Wang
> Assignee: Arshad Mohammad
> Priority: Critical
> Fix For: 3.5.3
>
> Attachments: ZOOKEEPER-2172-02.patch, ZOOKEEPER-2172-03.patch,
> ZOOKEEPER-2172-04.patch, ZOOKEEPER-2172.patch, ZOOKEPER-2172-05.patch,
> history.txt, node-1.log, node-2.log, node-3.log, zoo-1.log, zoo-2-1.log,
> zoo-2-2.log, zoo-2-3.log, zoo-2.log, zoo-2212-1.log, zoo-2212-2.log,
> zoo-2212-3.log, zoo-3-1.log, zoo-3-2.log, zoo-3-3.log, zoo-3.log,
> zoo-4-1.log, zoo-4-2.log, zoo-4-3.log, zoo.cfg.dynamic.10000005d,
> zoo.cfg.dynamic.next, zookeeper-1.log, zookeeper-1.out, zookeeper-2.log,
> zookeeper-2.out, zookeeper-3.log, zookeeper-3.out
>
>
> The operations are quite simple: start three zk servers one by one, then
> reconfig the cluster to add the new one as a participant. When I add the
> third one, the zk cluster may enter a weird state and cannot recover.
>
> I found “2015-04-20 12:53:48,236 [myid:1] - INFO [ProcessThread(sid:1
> cport:-1)::PrepRequestProcessor@547] - Incremental reconfig” in node-1 log.
> So the first node received the reconfig cmd at 12:53:48. Latter, it logged
> “2015-04-20 12:53:52,230 [myid:1] - ERROR
> [LearnerHandler-/10.0.0.2:55890:LearnerHandler@580] - Unexpected exception
> causing shutdown while sock still open” and “2015-04-20 12:53:52,231 [myid:1]
> - WARN [LearnerHandler-/10.0.0.2:55890:LearnerHandler@595] - ******* GOODBYE
> /10.0.0.2:55890 ********”. From then on, the first node and second node
> rejected all client connections and the third node didn’t join the cluster as
> a participant. The whole cluster was done.
>
> When the problem happened, all three nodes just used the same dynamic
> config file zoo.cfg.dynamic.10000005d which only contained the first two
> nodes. But there was another unused dynamic config file in node-1 directory
> zoo.cfg.dynamic.next which already contained three nodes.
>
> When I extended the waiting time between starting the third node and
> reconfiguring the cluster, the problem didn’t show again. So it should be a
> race condition problem.
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