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Posted to issues@hbase.apache.org by "Ted Yu (JIRA)" <ji...@apache.org> on 2013/05/10 01:34:13 UTC

[jira] [Commented] (HBASE-8519) Backup master will never come up if primary master dies during initialization

    [ https://issues.apache.org/jira/browse/HBASE-8519?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13653383#comment-13653383 ] 

Ted Yu commented on HBASE-8519:
-------------------------------

Looks like we can introduce another state, stored at beginning of initialization in clusterup znode, that signifies primary master tries to start the cluster.
ActiveMasterManager can check for this state to decide whether backup master should be brought up.
                
> Backup master will never come up if primary master dies during initialization
> -----------------------------------------------------------------------------
>
>                 Key: HBASE-8519
>                 URL: https://issues.apache.org/jira/browse/HBASE-8519
>             Project: HBase
>          Issue Type: Bug
>          Components: master
>    Affects Versions: 0.94.7, 0.95.0
>            Reporter: Jerry He
>            Assignee: Jerry He
>            Priority: Minor
>             Fix For: 0.98.0
>
>
> The problem happens if primary master dies after becoming master but before it completes initialization and calls clusterStatusTracker.setClusterUp(),
> The backup master will try to become the master, but will shutdown itself promptly because it sees 'the cluster is not up'.
> This is the backup master log:
> 2013-05-09 15:08:05,568 INFO org.apache.hadoop.hbase.master.metrics.MasterMetrics: Initialized
> 2013-05-09 15:08:05,573 DEBUG org.apache.hadoop.hbase.master.HMaster: HMaster started in backup mode.  Stalling until master znode is written.
> 2013-05-09 15:08:05,589 INFO org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper: Node /hbase/master already exists and this is not a retry
> 2013-05-09 15:08:05,590 INFO org.apache.hadoop.hbase.master.ActiveMasterManager: Adding ZNode for /hbase/backup-masters/xxx.com,60000,1368137285373 in backup master directory
> 2013-05-09 15:08:05,595 INFO org.apache.hadoop.hbase.master.ActiveMasterManager: Another master is the active master, xxx.com,60000,1368137283107; waiting to become the next active master
> 2013-05-09 15:09:45,006 DEBUG org.apache.hadoop.hbase.master.ActiveMasterManager: No master available. Notifying waiting threads
> 2013-05-09 15:09:45,006 INFO org.apache.hadoop.hbase.master.HMaster: Cluster went down before this master became active
> 2013-05-09 15:09:45,006 DEBUG org.apache.hadoop.hbase.master.HMaster: Stopping service threads
> 2013-05-09 15:09:45,006 INFO org.apache.hadoop.ipc.HBaseServer: Stopping server on 60000
>  
> In ActiveMasterManager::blockUntilBecomingActiveMaster()
>   ..
>   if (!clusterStatusTracker.isClusterUp()) {
>           this.master.stop(
>             "Cluster went down before this master became active");
>         }
>   ..

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