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https://issues.apache.org/jira/browse/HBASE-21844?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16761244#comment-16761244
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Sergey Shelukhin commented on HBASE-21844:
------------------------------------------

We were actually thinking about going back to 2.1/2.2 but the assignment in 
them is basically the same as in master (actually in 2.2 it's improved over 2.1 
it seems ;)). So the same issues would happen on 2.2, and probably on 2.1. We 
decided to freeze our master snapshot, backport bugfixes only, and wait for 2.2 
release to switch to that.

Yeah I like the idea of running master with mini-hbck at startup, with an 
explicit flag or config. That's sort of what I was referring to, in 20kft above 
:)

> 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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