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https://issues.apache.org/jira/browse/ZOOKEEPER-3756?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17059014#comment-17059014
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Mate Szalay-Beko commented on ZOOKEEPER-3756:
---------------------------------------------
> restarting the leader pod causes the cluster to be down for around 30 seconds
> while it restarts
No, usually a full cluster recovery shouldn't take more than a few seconds. At
least this is what I saw with normal clusters without Kubetnetes.
It would be interesting to see where ZooKeeper spend the 30 seconds. Is the
detection of the loosing of the old leader is slow? Or the new election is this
slow for some reason?
> I'm happy to close this and open a new issue if needed.
I would prefer to keep this one open. Partly to minimize the administration :)
and also there are some discussion / attachment here that is valuable for the
new issue too.
> Members failing to rejoin quorum
> --------------------------------
>
> Key: ZOOKEEPER-3756
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-3756
> Project: ZooKeeper
> Issue Type: Improvement
> Components: leaderElection
> Affects Versions: 3.5.6, 3.5.7
> Reporter: Dai Shi
> Assignee: Mate Szalay-Beko
> Priority: Major
> Attachments: Dockerfile, configmap.yaml, docker-entrypoint.sh,
> jmx.yaml, zoo-service.yaml, zookeeper.yaml
>
>
> Not sure if this is the place to ask, please close if it's not.
> I am seeing some behavior that I can't explain since upgrading to 3.5:
> In a 5 member quorum, when server 3 is the leader and each server has this in
> their configuration:
> {code:java}
> server.1=100.71.255.254:2888:3888:participant;2181
> server.2=100.71.255.253:2888:3888:participant;2181
> server.3=100.71.255.252:2888:3888:participant;2181
> server.4=100.71.255.251:2888:3888:participant;2181
> server.5=100.71.255.250:2888:3888:participant;2181{code}
> If servers 1 or 2 are restarted, they fail to rejoin the quorum with this in
> the logs:
> {code:java}
> 2020-03-11 20:23:35,720 [myid:2] - INFO
> [QuorumPeer[myid=2](plain=0.0.0.0:2181)(secure=disabled):QuorumPeer@1175] -
> LOOKING
> 2020-03-11 20:23:35,721 [myid:2] - INFO
> [QuorumPeer[myid=2](plain=0.0.0.0:2181)(secure=disabled):FastLeaderElection@885]
> - New election. My id = 2, proposed zxid=0x1b8005f4bba
> 2020-03-11 20:23:35,733 [myid:2] - INFO
> [WorkerSender[myid=2]:QuorumCnxManager@438] - Have smaller server identifier,
> so dropping the connection: (3, 2)
> 2020-03-11 20:23:35,734 [myid:2] - INFO
> [0.0.0.0/0.0.0.0:3888:QuorumCnxManager$Listener@924] - Received connection
> request 100.126.116.201:36140
> 2020-03-11 20:23:35,735 [myid:2] - INFO
> [WorkerSender[myid=2]:QuorumCnxManager@438] - Have smaller server identifier,
> so dropping the connection: (4, 2)
> 2020-03-11 20:23:35,740 [myid:2] - INFO
> [WorkerSender[myid=2]:QuorumCnxManager@438] - Have smaller server identifier,
> so dropping the connection: (5, 2)
> 2020-03-11 20:23:35,740 [myid:2] - INFO
> [0.0.0.0/0.0.0.0:3888:QuorumCnxManager$Listener@924] - Received connection
> request 100.126.116.201:36142
> 2020-03-11 20:23:35,740 [myid:2] - INFO
> [WorkerReceiver[myid=2]:FastLeaderElection@679] - Notification: 2 (message
> format version), 2 (n.leader), 0x1b8005f4bba (n.zxid), 0x1 (n.round), LOOKING
> (n.state), 2 (n.sid), 0x1b8 (n.peerEPoch), LOOKING (my state)0 (n.config
> version)
> 2020-03-11 20:23:35,742 [myid:2] - WARN
> [SendWorker:3:QuorumCnxManager$SendWorker@1143] - Interrupted while waiting
> for message on queue
> java.lang.InterruptedException
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.reportInterruptAfterWait(AbstractQueuedSynchronizer.java:2014)
> at
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2088)
> at
> java.util.concurrent.ArrayBlockingQueue.poll(ArrayBlockingQueue.java:418)
> at
> org.apache.zookeeper.server.quorum.QuorumCnxManager.pollSendQueue(QuorumCnxManager.java:1294)
> at
> org.apache.zookeeper.server.quorum.QuorumCnxManager.access$700(QuorumCnxManager.java:82)
> at
> org.apache.zookeeper.server.quorum.QuorumCnxManager$SendWorker.run(QuorumCnxManager.java:1131)
> 2020-03-11 20:23:35,744 [myid:2] - WARN
> [SendWorker:3:QuorumCnxManager$SendWorker@1153] - Send worker leaving thread
> id 3 my id = 2
> 2020-03-11 20:23:35,745 [myid:2] - WARN
> [RecvWorker:3:QuorumCnxManager$RecvWorker@1230] - Interrupting
> SendWorker{code}
> The only way I can seem to get them to rejoin the quorum is to restart the
> leader.
> However, if I remove server 4 and 5 from the configuration of server 1 or 2
> (so only servers 1, 2, and 3 remain in the configuration file), then they can
> rejoin the quorum fine. Is this expected and am I doing something wrong? Any
> help or explanation would be greatly appreciated. Thank you.
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