[ACCUMULO-3772] WAL prematurely deleted for root table

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 1.8.0
• Component/s: gc, tserver
• Labels: 1.7.0_QA

Environment

SHA1 2436eec237dc23608e91cae56777a323e2f77295 (I believe). Running with Kerberos on. HDFS 2.7.1-SNAPSHOT

• Assignee: Josh Elser
• Reporter: Josh Elser
• Created: 04/May/15 21:48
• Updated: 02/Jun/16 17:24
• Resolved: 21/May/15 17:20

Description

I have a 5-node test system which I ran all of the ITs against.

When I came back to the cluster later, I observed the following:

• Multiple running MinCs against accumulo.metadata that weren't running
• accumulo.root without an online tablet
• Multiple queued FATE ops (PopulateMetadata blocked).

Ultimately, found that recovery was repeatedly failing (without any notification on the monitor, mind you).

2015-05-04 21:44:16,151 [state.ZooTabletStateStore] DEBUG: root tablet log hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-4.novalocal+9997/fc0e8426-
f295-40d7-888e-f4b7dde1f966
2015-05-04 21:44:16,151 [state.ZooTabletStateStore] DEBUG: root tablet log hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-6.novalocal+9997/a1a2c22f-
f90d-4542-ab24-3ebdfa5d6fe4
2015-05-04 21:44:16,152 [state.ZooTabletStateStore] DEBUG: root tablet log hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-
f19e-4f43-bfc6-82f978b8ccb2
2015-05-04 21:44:16,152 [state.ZooTabletStateStore] DEBUG: Returning root tablet state: +r<<@(null,null,os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-6.novalocal:9997[34d1e090f8c0004])
2015-05-04 21:44:16,152 [master.Master] DEBUG: Root Table location State: +r<<@(null,null,os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-6.novalocal:9997[34d1e090f8c0004])
2015-05-04 21:44:16,152 [recovery.RecoveryManager] DEBUG: Recovering hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-4.novalocal+9997/fc0e8426-f295-4
0d7-888e-f4b7dde1f966 to hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/recovery/fc0e8426-f295-40d7-888e-f4b7dde1f966
2015-05-04 21:44:16,171 [recovery.RecoveryManager] DEBUG: Recovering hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-6.novalocal+9997/a1a2c22f-f90d-4
542-ab24-3ebdfa5d6fe4 to hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/recovery/a1a2c22f-f90d-4542-ab24-3ebdfa5d6fe4
2015-05-04 21:44:16,174 [recovery.RecoveryManager] DEBUG: Recovering hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-f19e-4
f43-bfc6-82f978b8ccb2 to hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/recovery/088e3c39-f19e-4f43-bfc6-82f978b8ccb2

Note 088e3c39-f19e-4f43-bfc6-82f978b8ccb2. Eventually we see that the file is gone:

2015-05-04 21:45:15,647 [recovery.RecoveryManager] DEBUG: Unable to initate log sort for hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-f19e-4f43-bfc6-82f978b8ccb2: java.io.FileNotFoundException: File does not exist: /apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-f19e-4f43-bfc6-82f978b8ccb2
        at org.apache.hadoop.hdfs.server.namenode.INodeFile.valueOf(INodeFile.java:71)
        at org.apache.hadoop.hdfs.server.namenode.INodeFile.valueOf(INodeFile.java:61)
        at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.recoverLease(FSNamesystem.java:2828)
        at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.recoverLease(NameNodeRpcServer.java:666)
        at org.apache.hadoop.hdfs.protocolPB.ClientNamenodeProtocolServerSideTranslatorPB.recoverLease(ClientNamenodeProtocolServerSideTranslatorPB.java:663)
        at org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos$ClientNamenodeProtocol$2.callBlockingMethod(ClientNamenodeProtocolProtos.java)
        at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:616)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:969)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2049)
        at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2045)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:415)
        at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1657)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2043)

The most likely candidate to direct hatred towards is the GC

[root@os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2 accumulo]# fgrep 088e3c39-f19e-4f43-bfc6-82f978b8ccb2 gc_os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal.debug.log
2015-05-04 08:30:15,210 [gc.GarbageCollectWriteAheadLogs] INFO : Checking replication table for hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-f19e-4f43-bfc6-82f978b8ccb2
2015-05-04 08:30:15,223 [gc.GarbageCollectWriteAheadLogs] DEBUG: WAL not needed for replication hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-f19e-4f43-bfc6-82f978b8ccb2
2015-05-04 08:30:15,268 [gc.GarbageCollectWriteAheadLogs] DEBUG: Removing unused WAL for server os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal:9997[14d1df69c910000] log hdfs://os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-2.novalocal:8020/apps/accumulo/data/wal/os-hdp-2-3-amb-r6-1430724014-sec-accumulo-1-5.novalocal+9997/088e3c39-f19e-4f43-bfc6-82f978b8ccb2

Sure enough, the GC deleted the file. I'll be digging from here...

Issue Links

• is broken by: ACCUMULO-3423 speed up WAL roll-overs
• is related to: ACCUMULO-4157 WAL can be prematurely deleted