[ https://issues.apache.org/jira/browse/HBASE-21811?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Duo Zhang updated HBASE-21811: ------------------------------ Attachment: HBASE-21811-v1.patch > 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 > Fix For: 3.0.0, 2.2.0 > > Attachments: HBASE-21811-UT.patch, HBASE-21811-v1.patch, > HBASE-21811.patch > > > 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. -- This message was sent by Atlassian JIRA (v7.6.3#76005)