[jira] [Comment Edited] (HBASE-21742) master can create bad procedures during abort, making entire cluster unusable

["Sergey Shelukhin (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-21742?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16749199#comment-16749199 ] 

Sergey Shelukhin edited comment on HBASE-21742 at 1/22/19 10:06 PM:
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This is on master (mid-December).
The problem is not that SCP gave up... the problem is that SCP was created with incorrect state during master shutdown, and preserved in procedure WAL.
So, there was no SCP at all with meta flag set (the server holding meta had SCP with meta=false), and all SCPs were waiting for someone else to recover meta.



was (Author: sershe):
This is on master.
The problem is not that SCP gave up... the problem is that SCP was created with incorrect state during master shutdown, and preserved in procedure WAL.
So, there was no SCP at all with meta flag set (the server holding meta had SCP with meta=false), and all SCPs were waiting for someone else to recover meta.


> master can create bad procedures during abort, making entire cluster unusable
> -----------------------------------------------------------------------------
>
>                 Key: HBASE-21742
>                 URL: https://issues.apache.org/jira/browse/HBASE-21742
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 3.0.0
>            Reporter: Sergey Shelukhin
>            Priority: Critical
>
> Some small HDFS hiccup causes master and meta RS to fail together. Master goes first:
> {noformat}
> 2019-01-18 08:09:46,790 INFO  [KeepAlivePEWorker-311] zookeeper.MetaTableLocator: Setting hbase:meta (replicaId=0) location in ZooKeeper as meta-rs,17020,1547824792484
> ...
> 2019-01-18 10:01:16,904 ERROR [PEWorker-11] master.HMaster: ***** ABORTING master master,17000,1547604554447: FAILED [blah] *****
> ...
> 2019-01-18 10:01:17,087 INFO  [master/master:17000] assignment.AssignmentManager: Stopping assignment manager
> {noformat}
> Bunch of stuff keeps happening, including procedure retries, which is also suspect, but not the point here:
> {noformat}
> 2019-01-18 10:01:21,598 INFO  [PEWorker-3] procedure2.TimeoutExecutorThread: ADDED pid=104031, state=WAITING_TIMEOUT:REGION_STATE_TRANSITION_CLOSE, ... {noformat}
> {noformat}
> Then the meta RS decides it's time to go:
> {noformat}
> 2019-01-18 10:01:25,319 INFO  [RegionServerTracker-0] master.RegionServerTracker: RegionServer ephemeral node deleted, processing expiration [meta-rs,17020,1547824792484]
> ...
> 2019-01-18 10:01:25,463 INFO  [RegionServerTracker-0] assignment.AssignmentManager: Added meta-rs,17020,1547824792484 to dead servers which carryingMeta=false, submitted ServerCrashProcedure pid=104313
> {noformat}
> This SCP gets persisted, so when the next master starts, it waits forever for meta to be onlined, while there's no SCP with meta=true to online it.
> The only way around this is to delete the procv2 WAL - master has all the information here, as it often does in bugs I've found recently, but some split brain procedures cause it to get stuck one way or another.
> I will file a separate bug about that.



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