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https://issues.apache.org/jira/browse/HBASE-13605?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14523986#comment-14523986
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Jimmy Xiang commented on HBASE-13605:
-------------------------------------
The dead server list in RegionStates is a list of servers that are dead and
have been processed by SSH. It is used by AM to make sure regions are not
assigned before SSH has finished log-splitting. It is critical to make sure
there is no data loss.
RegionStates does not know if a server is dead unless SSH tells it. If the
server is not dead, but it is on the dead server list in the RegionStates, this
is possible only if your cluster has some time sync issue. I was wondering how
this actually happened. There may be some clue in the log.
> RegionStates should not keep its list of dead servers
> -----------------------------------------------------
>
> Key: HBASE-13605
> URL: https://issues.apache.org/jira/browse/HBASE-13605
> Project: HBase
> Issue Type: Bug
> Reporter: Enis Soztutar
> Assignee: Enis Soztutar
> Fix For: 2.0.0, 1.0.2, 1.1.1
>
> Attachments: hbase-13605_v1.patch
>
>
> As mentioned in
> https://issues.apache.org/jira/browse/HBASE-9514?focusedCommentId=13769761&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13769761
> and HBASE-12844 we should have only 1 source of cluster membership.
> The list of dead server and RegionStates doing it's own liveliness check
> (ServerManager.isServerReachable()) has caused an assignment problem again in
> a test cluster where the region states "thinks" that the server is dead and
> SSH will handle the region assignment. However the RS is not dead at all,
> living happily, and never gets zk expiry or YouAreDeadException or anything.
> This leaves the list of regions unassigned in OFFLINE state.
> master assigning the region:
> {code}
> 15-04-20 09:02:25,780 DEBUG [AM.ZK.Worker-pool3-t330] master.RegionStates:
> Onlined 77dddcd50c22e56bfff133c0e1f9165b on
> os-amb-r6-us-1429512014-hbase4-6.novalocal,16020,1429520535268 {ENCODED =>
> 77dddcd50c
> {code}
> Master then disabled the table, and unassigned the region:
> {code}
> 2015-04-20 09:02:27,158 WARN [ProcedureExecutorThread-1]
> zookeeper.ZKTableStateManager: Moving table loadtest_d1 state from DISABLING
> to DISABLING
> Starting unassign of
> loadtest_d1,,1429520544378.77dddcd50c22e56bfff133c0e1f9165b. (offlining),
> current state: {77dddcd50c22e56bfff133c0e1f9165b state=OPEN,
> ts=1429520545780,
> server=os-amb-r6-us-1429512014-hbase4-6.novalocal,16020,1429520535268}
> bleProcedure$BulkDisabler-0] master.AssignmentManager: Sent CLOSE to
> os-amb-r6-us-1429512014-hbase4-6.novalocal,16020,1429520535268 for region
> loadtest_d1,,1429520544378.77dddcd50c22e56bfff133c0e1f9165b.
> 2015-04-20 09:02:27,414 INFO [AM.ZK.Worker-pool3-t316] master.RegionStates:
> Offlined 77dddcd50c22e56bfff133c0e1f9165b from
> os-amb-r6-us-1429512014-hbase4-6.novalocal,16020,1429520535268
> {code}
> On table re-enable, AM does not assign the region:
> {code}
> 2015-04-20 09:02:30,415 INFO [ProcedureExecutorThread-3]
> balancer.BaseLoadBalancer: Reassigned 25 regions. 25 retained the pre-restart
> assignment.ยท
> 2015-04-20 09:02:30,415 INFO [ProcedureExecutorThread-3]
> procedure.EnableTableProcedure: Bulk assigning 25 region(s) across 5
> server(s), retainAssignment=true
> l,16000,1429515659726-GeneralBulkAssigner-4] master.RegionStates: Couldn't
> reach online server
> os-amb-r6-us-1429512014-hbase4-6.novalocal,16020,1429520535268
> l,16000,1429515659726-GeneralBulkAssigner-4] master.AssignmentManager:
> Updating the state to OFFLINE to allow to be reassigned by SSH
> nmentManager: Skip assigning
> loadtest_d1,,1429520544378.77dddcd50c22e56bfff133c0e1f9165b., it is on a dead
> but not processed yet server:
> os-amb-r6-us-1429512014-hbase4-6.novalocal,16020,1429520535268
> {code}
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