[jira] [Resolved] (HBASE-14190) Assign system tables ahead of user region assignment

["Andrew Kyle Purtell (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HBASE-14190?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrew Kyle Purtell resolved HBASE-14190.
-----------------------------------------
    Resolution: Not A Problem

> Assign system tables ahead of user region assignment
> ----------------------------------------------------
>
>                 Key: HBASE-14190
>                 URL: https://issues.apache.org/jira/browse/HBASE-14190
>             Project: HBase
>          Issue Type: Bug
>          Components: Region Assignment
>            Reporter: Ted Yu
>            Assignee: Ted Yu
>            Priority: Critical
>         Attachments: 14190-system-wal-v1.txt, 14190-v12.4.txt, 14190-v12.txt
>
>
> Currently the namespace table region is assigned like user regions.
> I spent several hours working with a customer where master couldn't finish initialization.
> Even though master was restarted quite a few times, it went down with the following:
> {code}
> 2015-08-05 17:16:57,530 FATAL [hdpmaster1:60000.activeMasterManager] master.HMaster: Master server abort: loaded coprocessors are: []
> 2015-08-05 17:16:57,530 FATAL [hdpmaster1:60000.activeMasterManager] master.HMaster: Unhandled exception. Starting shutdown.
> java.io.IOException: Timedout 300000ms waiting for namespace table to be assigned
>   at org.apache.hadoop.hbase.master.TableNamespaceManager.start(TableNamespaceManager.java:104)
>   at org.apache.hadoop.hbase.master.HMaster.initNamespace(HMaster.java:985)
>   at org.apache.hadoop.hbase.master.HMaster.finishActiveMasterInitialization(HMaster.java:779)
>   at org.apache.hadoop.hbase.master.HMaster.access$500(HMaster.java:182)
>   at org.apache.hadoop.hbase.master.HMaster$1.run(HMaster.java:1646)
>   at java.lang.Thread.run(Thread.java:744)
> {code}
> During previous run(s), namespace table was created, hence leaving an entry in hbase:meta.
> The following if block in TableNamespaceManager#start() was skipped:
> {code}
>     if (!MetaTableAccessor.tableExists(masterServices.getConnection(),
>       TableName.NAMESPACE_TABLE_NAME)) {
> {code}
> TableNamespaceManager#start() spins, waiting for namespace region to be assigned.
> There was issue in master assigning user regions.
> We tried issuing 'assign' command from hbase shell which didn't work because of the following check in MasterRpcServices#assignRegion():
> {code}
>       master.checkInitialized();
> {code}
> This scenario can be avoided if we assign hbase:namespace table after hbase:meta is assigned but before user table region assignment.



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