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Flavio Junqueira commented on ZOOKEEPER-2247: --------------------------------------------- [~rakesh_r] It sounds ok to add to the predicate a call to {{!zk.hasInternalError()}} as you propose, but why can't we simply make {{self.isRunning()}} return false in the case of an error by setting running to false? That's what we want, that the server stops running in the case of an error, right? {{QuorumPeer.isRunning()}} returns the value of {{QuorumPeer.running}}, which is the condition to keep running the main loop, so we don't want to set it to false. It sounds like using {{QuorumPeer.isRunning()}} as is with follower, observer, learner, and leader isn't great because there are scenarios (like the one discussed here) in which we want to shutdown a participant/observer, but not the quorum peer. We may want to have a {{isRunning()}} for the follower, observer, learner, and leader classes that returns something like {{running && !zk.hasInternalError()}}. We may need to implement a {{isRunning()}} method for each one of those classes because they might eventually have different predicates to determine whether they are running or not. Does it make sense? > Zookeeper service becomes unavailable when leader fails to write transaction > log > -------------------------------------------------------------------------------- > > Key: ZOOKEEPER-2247 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2247 > Project: ZooKeeper > Issue Type: Bug > Affects Versions: 3.5.0 > Reporter: Arshad Mohammad > Assignee: Arshad Mohammad > Priority: Critical > Fix For: 3.4.8, 3.5.2 > > Attachments: ZOOKEEPER-2247-01.patch, ZOOKEEPER-2247-02.patch, > ZOOKEEPER-2247-03.patch, ZOOKEEPER-2247-04.patch, ZOOKEEPER-2247-05.patch, > ZOOKEEPER-2247-06.patch > > > Zookeeper service becomes unavailable when leader fails to write transaction > log. Bellow are the exceptions > {code} > 2015-08-14 15:41:18,556 [myid:100] - ERROR > [SyncThread:100:ZooKeeperCriticalThread@48] - Severe unrecoverable error, > from thread : SyncThread:100 > java.io.IOException: Input/output error > at sun.nio.ch.FileDispatcherImpl.force0(Native Method) > at sun.nio.ch.FileDispatcherImpl.force(FileDispatcherImpl.java:76) > at sun.nio.ch.FileChannelImpl.force(FileChannelImpl.java:376) > at > org.apache.zookeeper.server.persistence.FileTxnLog.commit(FileTxnLog.java:331) > at > org.apache.zookeeper.server.persistence.FileTxnSnapLog.commit(FileTxnSnapLog.java:380) > at org.apache.zookeeper.server.ZKDatabase.commit(ZKDatabase.java:563) > at > org.apache.zookeeper.server.SyncRequestProcessor.flush(SyncRequestProcessor.java:178) > at > org.apache.zookeeper.server.SyncRequestProcessor.run(SyncRequestProcessor.java:113) > 2015-08-14 15:41:18,559 [myid:100] - INFO > [SyncThread:100:ZooKeeperServer$ZooKeeperServerListenerImpl@500] - Thread > SyncThread:100 exits, error code 1 > 2015-08-14 15:41:18,559 [myid:100] - INFO > [SyncThread:100:ZooKeeperServer@523] - shutting down > 2015-08-14 15:41:18,560 [myid:100] - INFO > [SyncThread:100:SessionTrackerImpl@232] - Shutting down > 2015-08-14 15:41:18,560 [myid:100] - INFO > [SyncThread:100:LeaderRequestProcessor@77] - Shutting down > 2015-08-14 15:41:18,560 [myid:100] - INFO > [SyncThread:100:PrepRequestProcessor@1035] - Shutting down > 2015-08-14 15:41:18,560 [myid:100] - INFO > [SyncThread:100:ProposalRequestProcessor@88] - Shutting down > 2015-08-14 15:41:18,561 [myid:100] - INFO > [SyncThread:100:CommitProcessor@356] - Shutting down > 2015-08-14 15:41:18,561 [myid:100] - INFO > [CommitProcessor:100:CommitProcessor@191] - CommitProcessor exited loop! > 2015-08-14 15:41:18,562 [myid:100] - INFO > [SyncThread:100:Leader$ToBeAppliedRequestProcessor@915] - Shutting down > 2015-08-14 15:41:18,562 [myid:100] - INFO > [SyncThread:100:FinalRequestProcessor@646] - shutdown of request processor > complete > 2015-08-14 15:41:18,562 [myid:100] - INFO > [SyncThread:100:SyncRequestProcessor@191] - Shutting down > 2015-08-14 15:41:18,563 [myid:100] - INFO [ProcessThread(sid:100 > cport:-1)::PrepRequestProcessor@159] - PrepRequestProcessor exited loop! > {code} > After this exception Leader server still remains leader. After this non > recoverable exception the leader should go down and let other followers > become leader. -- This message was sent by Atlassian JIRA (v6.3.4#6332)