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https://issues.apache.org/jira/browse/HBASE-21811?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sean Busbey updated HBASE-21811:
--------------------------------
Component/s: amv2
> region can be opened on two servers due to race condition with procedures and
> server reports
> --------------------------------------------------------------------------------------------
>
> Key: HBASE-21811
> URL: https://issues.apache.org/jira/browse/HBASE-21811
> Project: HBase
> Issue Type: Bug
> Components: amv2
> Affects Versions: 3.0.0
> Reporter: Sergey Shelukhin
> Assignee: Sergey Shelukhin
> Priority: Blocker
>
> Looks like the region server responses are being processed incorrectly in
> places allowing te region to be opened on two servers.
> * The region server report handling in procedures should check which server
> is reporting.
> * Also although I didn't check (and it isn't implicated in this bug), RS must
> check in OPEN that it's actually the correct RS master sent open to (w.r.t.
> start timestamp)
> This was previosuly "mitigated" by master killing the RS with incorrect
> reports, but due to race conditions with reports and assignment the kill was
> replaced with a warning, so now this condition persists.
> Regardless, the kill approach is not a good fix because there's still a
> window when a region can be opened on two servers.
> A region is being opened by server_48c. The server dies, and we process the
> retry correctly (retry=3 because 2 previous similar open failures were
> processed correctly).
> We start opening it on server_1aa now.
> {noformat}
> 2019-01-28 18:12:09,862 INFO [KeepAlivePEWorker-104]
> assignment.RegionStateStore: pid=4915 updating hbase:meta
> row=8be2a423b16471b9417f0f7de04281c6, regionState=ABNORMALLY_CLOSED
> 2019-01-28 18:12:09,862 INFO [KeepAlivePEWorker-104]
> procedure.ServerCrashProcedure: pid=11944,
> state=RUNNABLE:SERVER_CRASH_ASSIGN, hasLock=true; ServerCrashProcedure
> server=server_48c,17020,1548726406632, splitWal=true, meta=false found RIT
> pid=4915, ppid=7, state=WAITING:REGION_STATE_TRANSITION_CONFIRM_OPENED,
> hasLock=true; TransitRegionStateProcedure table=table,
> region=8be2a423b16471b9417f0f7de04281c6, ASSIGN; rit=OPENING,
> location=server_48c,17020,1548726406632, table=table,
> region=8be2a423b16471b9417f0f7de04281c6
> 2019-01-28 18:12:10,778 INFO [KeepAlivePEWorker-80]
> assignment.TransitRegionStateProcedure: Retry=3 of max=2147483647; pid=4915,
> ppid=7, state=RUNNABLE:REGION_STATE_TRANSITION_CONFIRM_OPENED, hasLock=true;
> TransitRegionStateProcedure table=table,
> region=8be2a423b16471b9417f0f7de04281c6, ASSIGN; rit=ABNORMALLY_CLOSED,
> location=null
> ...
> 2019-01-28 18:12:10,902 INFO [KeepAlivePEWorker-80]
> assignment.TransitRegionStateProcedure: Starting pid=4915, ppid=7,
> state=RUNNABLE:REGION_STATE_TRANSITION_GET_ASSIGN_CANDIDATE, hasLock=true;
> TransitRegionStateProcedure table=table,
> region=8be2a423b16471b9417f0f7de04281c6, ASSIGN; rit=ABNORMALLY_CLOSED,
> location=null; forceNewPlan=true, retain=false
> 2019-01-28 18:12:11,114 INFO [PEWorker-7] assignment.RegionStateStore:
> pid=4915 updating hbase:meta row=8be2a423b16471b9417f0f7de04281c6,
> regionState=OPENING, regionLocation=server_1aa,17020,1548727658713
> {noformat}
> However, we get the remote procedure failure from 48c after we've already
> started that.
> It actually tried to open on the restarted RS, which makes me wonder if this
> is safe also w.r.t. other races - what if RS already initialized and didn't
> error out?
> Need to check if we verify the start code expected by master on RS when
> opening.
> {noformat}
> 2019-01-28 18:12:12,179 WARN [RSProcedureDispatcher-pool4-t362]
> assignment.RegionRemoteProcedureBase: The remote operation pid=11050,
> ppid=4915, state=SUCCESS, hasLock=false;
> org.apache.hadoop.hbase.master.assignment.OpenRegionProcedure for region
> {ENCODED => 8be2a423b16471b9417f0f7de04281c6 ... to server
> server_48c,17020,1548726406632 failed
> org.apache.hadoop.hbase.ipc.ServerNotRunningYetException:
> org.apache.hadoop.hbase.ipc.ServerNotRunningYetException: Server
> server_48c,17020,1548727752747 is not running yet
> 2019-01-28 18:12:12,179 WARN [RSProcedureDispatcher-pool4-t362]
> procedure.RSProcedureDispatcher: server server_48c,17020,1548726406632 is not
> up for a while; try a new one
> {noformat}
> Without any other reason (at least logged), the RIT immediately retries again
> and chooses a new candidate. It then retries again and goes to the new 48c,
> but that's unrelated.
> {noformat}
> 2019-01-28 18:12:12,289 INFO [KeepAlivePEWorker-100]
> assignment.TransitRegionStateProcedure: Retry=4 of max=2147483647; pid=4915,
> ppid=7, state=RUNNABLE:REGION_STATE_TRANSITION_CONFIRM_OPENED, hasLock=true;
> TransitRegionStateProcedure table=table,
> region=8be2a423b16471b9417f0f7de04281c6, ASSIGN; rit=OPENING,
> location=server_1aa,17020,1548727658713
> ...
> 2019-01-28 18:12:12,668 INFO [PEWorker-9] assignment.RegionStateStore:
> pid=4915 updating hbase:meta row=8be2a423b16471b9417f0f7de04281c6,
> regionState=OPENING, regionLocation=server_fd3,17020,1548727536972
> ....
> 2019-01-28 18:26:29,480 INFO [KeepAlivePEWorker-154]
> assignment.RegionStateStore: pid=4915 updating hbase:meta
> row=8be2a423b16471b9417f0f7de04281c6, regionState=OPENING,
> regionLocation=server_48c,17020,1548727752747
> {noformat}
> What does happen though is that 1aa, that never got a chance to respond at
> the time that the RIT erroneously retried above, finishes opening the region
> - which master ignores
> {noformat}
> 2019-01-28 18:27:42,424 WARN
> [RpcServer.default.FPBQ.Fifo.handler=29,queue=4,port=17000]
> assignment.TransitRegionStateProcedure: Received report OPENED transition
> from server_1aa,17020,1548727658713 for rit=OPENING,
> location=server_48c,17020,1548727752747, table=table,
> region=8be2a423b16471b9417f0f7de04281c6, pid=4915 but the region is not on
> it, should be a retry, ignore
> {noformat}
> And starts spamming these warnings until finally the region is open in two
> places.
> {noformat}
> 2019-01-28 18:27:45,500 WARN
> [RpcServer.default.FPBQ.Fifo.handler=42,queue=2,port=17000]
> assignment.AssignmentManager: rit=OPENING,
> location=server_48c,17020,1548727752747, table=table,
> region=8be2a423b16471b9417f0f7de04281c6 reported OPEN on
> server=server_1aa,17020,1548727658713 but state has otherwise
> ...
> 2019-01-28 18:51:21,197 WARN
> [RpcServer.default.FPBQ.Fifo.handler=10,queue=0,port=17000]
> assignment.AssignmentManager: rit=OPEN,
> location=server_48c,17020,1548727752747, table=table,
> region=8be2a423b16471b9417f0f7de04281c6 reported OPEN on
> server=server_1aa,17020,1548727658713 but state has otherwise
> {noformat}
> This can result in data loss.
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