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https://issues.apache.org/jira/browse/HBASE-28366?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17817535#comment-17817535
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Viraj Jasani commented on HBASE-28366:
--------------------------------------
The fact that we had logs mentioned in above comment clearly says that even for
old server, we were not able to throw YouAreDeadException. If we were, we would
not have these logs.
{code:java}
public void regionServerReport(ServerName sn, ServerMetrics sl) throws
YouAreDeadException {
checkIsDead(sn, "REPORT");
if (null == this.onlineServers.replace(sn, sl)) {
// Already have this host+port combo and its just different start code?
// Just let the server in. Presume master joining a running cluster.
// recordNewServer is what happens at the end of reportServerStartup.
// The only thing we are skipping is passing back to the regionserver
// the ServerName to use. Here we presume a master has already done
// that so we'll press on with whatever it gave us for ServerName.
if (!checkAndRecordNewServer(sn, sl)) {
LOG.info("RegionServerReport ignored, could not record the server: " +
sn);
return; // Not recorded, so no need to move on
}
}
updateLastFlushedSequenceIds(sn, sl);
} {code}
Here, only checkIsDead() throws YouAreDeadException.
So we have problem: for the same host+port combination with different start
code, we are log that the report is ignored but we still proceed with recording
the report report:
{code:java}
ServerMetrics newLoad =
ServerMetricsBuilder.toServerMetrics(serverName, versionNumber, version, sl);
server.getServerManager().regionServerReport(serverName, newLoad);
server.getAssignmentManager().reportOnlineRegions(serverName,
newLoad.getRegionMetrics().keySet());{code}
We can easily create inconsistencies if we just return gracefully from
regionServerReport() even though the server was not successfully recorded, we
should throw YouAreDeadException even here, because the start code is old and
we have record of new online server with new start code.
> Mis-order of SCP and regionServerReport results into region inconsistencies
> ---------------------------------------------------------------------------
>
> Key: HBASE-28366
> URL: https://issues.apache.org/jira/browse/HBASE-28366
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.4.17, 3.0.0-beta-1, 2.5.7
> Reporter: Viraj Jasani
> Assignee: Viraj Jasani
> Priority: Major
>
> If the regionserver is online but due to network issue, if it's rs ephemeral
> node gets deleted in zookeeper, active master schedules the SCP. However, if
> the regionserver is alive, it can still send regionServerReport to active
> master. In the case where SCP assigns regions to other regionserver that were
> previously hosted on the old regionserver (which is still alive), the old rs
> can continue to sent regionServerReport to active master.
> Eventually this results into region inconsistencies because region is alive
> on two regionservers at the same time (though it's temporary state because
> the rs will be aborted soon). While old regionserver can have zookeeper
> connectivity issues, it can still make rpc calls to active master.
> Logs:
> SCP:
> {code:java}
> 2024-01-29 16:50:33,956 INFO [RegionServerTracker-0]
> assignment.AssignmentManager - Scheduled ServerCrashProcedure pid=9812440 for
> server1-114.xyz,61020,1706541866103 (carryingMeta=false)
> server1-114.xyz,61020,1706541866103/CRASHED/regionCount=364/lock=java.util.concurrent.locks.ReentrantReadWriteLock@5d5fc31[Write
> locks = 1, Read locks = 0], oldState=ONLINE.
> 2024-01-29 16:50:33,956 DEBUG [RegionServerTracker-0]
> procedure2.ProcedureExecutor - Stored pid=9812440,
> state=RUNNABLE:SERVER_CRASH_START; ServerCrashProcedure
> server1-114.xyz,61020,1706541866103, splitWal=true, meta=false
> 2024-01-29 16:50:33,973 INFO [PEWorker-36] procedure.ServerCrashProcedure -
> Splitting WALs pid=9812440, state=RUNNABLE:SERVER_CRASH_SPLIT_LOGS,
> locked=true; ServerCrashProcedure server1-114.xyz,61020,1706541866103,
> splitWal=true, meta=false, isMeta: false
> {code}
> As part of SCP, d743ace9f70d55f55ba1ecc6dc49a5cb was assigned to another
> server:
>
> {code:java}
> 2024-01-29 16:50:42,656 INFO [PEWorker-24] procedure.MasterProcedureScheduler
> - Took xlock for pid=9818494, ppid=9812440,
> state=RUNNABLE:REGION_STATE_TRANSITION_GET_ASSIGN_CANDIDATE;
> TransitRegionStateProcedure
> table=PLATFORM_ENTITY.PLATFORM_IMMUTABLE_ENTITY_DATA,
> region=d743ace9f70d55f55ba1ecc6dc49a5cb, ASSIGN
> 2024-01-29 16:50:43,106 INFO [PEWorker-23] assignment.RegionStateStore -
> pid=9818494 updating hbase:meta row=d743ace9f70d55f55ba1ecc6dc49a5cb,
> regionState=OPEN, repBarrier=12867482, openSeqNum=12867482,
> regionLocation=server1-65.xyz,61020,1706165574050
> {code}
>
> rs abort, after ~5 min:
> {code:java}
> 2024-01-29 16:54:27,235 ERROR [regionserver/server1-114:61020]
> regionserver.HRegionServer - ***** ABORTING region server
> server1-114.xyz,61020,1706541866103: Unexpected exception handling getData
> *****
> org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode
> = ConnectionLoss for /hbase/master
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:102)
> at org.apache.zookeeper.KeeperException.create(KeeperException.java:54)
> at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1229)
> at
> org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.getData(RecoverableZooKeeper.java:414)
> at
> org.apache.hadoop.hbase.zookeeper.ZKUtil.getDataInternal(ZKUtil.java:403)
> at
> org.apache.hadoop.hbase.zookeeper.ZKUtil.getDataAndWatch(ZKUtil.java:367)
> at
> org.apache.hadoop.hbase.zookeeper.ZKNodeTracker.getData(ZKNodeTracker.java:180)
> at
> org.apache.hadoop.hbase.zookeeper.MasterAddressTracker.getMasterAddress(MasterAddressTracker.java:152)
> at
> org.apache.hadoop.hbase.regionserver.HRegionServer.createRegionServerStatusStub(HRegionServer.java:2892)
> at
> org.apache.hadoop.hbase.regionserver.HRegionServer.tryRegionServerReport(HRegionServer.java:1352)
> at
> org.apache.hadoop.hbase.regionserver.HRegionServer.run(HRegionServer.java:1142)
> {code}
>
> Several region transition failure report logs:
> {code:java}
> 2024-01-29 16:55:13,029 INFO [_REGION-regionserver/server1-114:61020-0]
> regionserver.HRegionServer - Failed report transition server { host_name:
> "server1-114.xyz" port: 61020 start_code: 1706541866103 } transition {
> transition_code: CLOSED region_info { region_id: 1671555604277 table_name {
> namespace: "default" qualifier: "TABLE1" } start_key: "abc" end_key: "xyz"
> offline: false split: false replica_id: 0 } proc_id: -1 }; retry (#0)
> immediately.
> java.net.UnknownHostException: Call to address=master-server1.xyz:61000
> failed on local exception: java.net.UnknownHostException:
> master-server1.xyz:61000 could not be resolved
> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> at
> sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
> at
> sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
> at org.apache.hadoop.hbase.ipc.IPCUtil.wrapException(IPCUtil.java:239)
> at
> org.apache.hadoop.hbase.ipc.AbstractRpcClient.onCallFinished(AbstractRpcClient.java:391)
> at
> org.apache.hadoop.hbase.ipc.AbstractRpcClient.access$100(AbstractRpcClient.java:92)
> at
> org.apache.hadoop.hbase.ipc.AbstractRpcClient$3.run(AbstractRpcClient.java:425)
> at
> org.apache.hadoop.hbase.ipc.AbstractRpcClient$3.run(AbstractRpcClient.java:420)
> at org.apache.hadoop.hbase.ipc.Call.callComplete(Call.java:114)
> at org.apache.hadoop.hbase.ipc.Call.setException(Call.java:129)
> at
> org.apache.hadoop.hbase.ipc.NettyRpcConnection.lambda$sendRequest$4(NettyRpcConnection.java:365)
> at
> org.apache.hbase.thirdparty.io.netty.util.concurrent.AbstractEventExecutor.runTask(AbstractEventExecutor.java:174)
> at
> org.apache.hbase.thirdparty.io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:167)
> at
> org.apache.hbase.thirdparty.io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:470)
> at
> org.apache.hbase.thirdparty.io.netty.channel.epoll.EpollEventLoop.run(EpollEventLoop.java:403)
> at
> org.apache.hbase.thirdparty.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997)
> at
> org.apache.hbase.thirdparty.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
> at
> org.apache.hbase.thirdparty.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
> at java.lang.Thread.run(Thread.java:750)
> Caused by: java.net.UnknownHostException: master-server1.xyz:61000 could not
> be resolved
> at
> org.apache.hadoop.hbase.ipc.RpcConnection.getRemoteInetAddress(RpcConnection.java:192)
> at
> org.apache.hadoop.hbase.ipc.NettyRpcConnection.connect(NettyRpcConnection.java:280)
> at
> org.apache.hadoop.hbase.ipc.NettyRpcConnection.access$900(NettyRpcConnection.java:79)
> at
> org.apache.hadoop.hbase.ipc.NettyRpcConnection$5.run(NettyRpcConnection.java:340)
> at
> org.apache.hadoop.hbase.ipc.HBaseRpcControllerImpl.notifyOnCancel(HBaseRpcControllerImpl.java:259)
> at
> org.apache.hadoop.hbase.ipc.NettyRpcConnection.sendRequest0(NettyRpcConnection.java:323)
> at
> org.apache.hadoop.hbase.ipc.NettyRpcConnection.lambda$sendRequest$4(NettyRpcConnection.java:363)
> ... 8 more
> {code}
>
> The server is later started after sometime:
> {code:java}
> Mon Jan 29 17:01:35 UTC 2024 Starting regionserver on server1-114.xyz
> core file size (blocks, -c) unlimited
> ...
> ... {code}
>
> In order to avoid region inconsistencies, we should clear regionserver ->
> region reported map from active master. We can do it in two ways:
> # Active: master should throw error while serving regionServerReport call if
> the server is already considered dead due to deletion of ephemeral znode.
> # Passive: run a chore that can compare the regionserver -> region map
> generated from the regionserver reports with the actual live servers based on
> the zk tracking, and remove any rs report that is no longer valid.
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