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https://issues.apache.org/jira/browse/HBASE-21844?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16760745#comment-16760745
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Wellington Chevreuil commented on HBASE-21844:
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This may look similar to HBASE-21843, but difference is that on HBASE-21843
meta is coming online with an old state somehow, not reflecting updates made on
a previous SCP "successful" run. That problem affects mostly user tables, but
may also impact namespace table, in which case master becomes stuck with
similar symptoms from this HBASE-21844 (however, it's namespace that's not
coming online, instead of meta) . I believe this patch will fix namespace issue
as well (isRegionOnline is also called for namespace), since it will submit a
new SCP for the server currently assigned to it, but not user table regions.
Those would remain unassigned, and would still require the extra checks from
HBASE-21843.
> Master could get stuck in initializing state while waiting for meta
> -------------------------------------------------------------------
>
> Key: HBASE-21844
> URL: https://issues.apache.org/jira/browse/HBASE-21844
> Project: HBase
> Issue Type: Bug
> Components: master, meta
> Affects Versions: 3.0.0
> Reporter: Bahram Chehrazy
> Assignee: Bahram Chehrazy
> Priority: Major
> Attachments:
> 0001-HBASE-21844-Handling-incorrect-Meta-state-on-Zookeep.patch
>
>
> If the active master crashes after meta server dies, there is a slight chance
> of master getting into a state where the ZK says meta is OPEN, but the server
> is dead and there is no active SCP to recover it (perhaps the SCP has aborted
> and the procWALs were corrupted). In this case the waitForMetaOnline never
> returns.
>
> We've seen this happening a few times when there had been a temporary HDFS
> outage. Following log lines shows this state.
>
> 2019-01-17 18:55:48,497 WARN [master/************:16000:becomeActiveMaster]
> master.HMaster: hbase:meta,,1.1588230740 is NOT online; state=
> {1588230740 *state=*OPEN**, ts=1547780128227,
> server=*************,16020,1547776821322}
> ; *ServerCrashProcedures=false*. Master startup cannot progress, in
> holding-pattern until region onlined.
>
> I'm still investigating why and how to prevent getting into this bad state,
> but nevertheless the master should be able to recover during a restart by
> initiating a new SCP to fix the meta.
>
>
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