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https://issues.apache.org/jira/browse/HBASE-5926?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13506801#comment-13506801
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Jean-Daniel Cryans commented on HBASE-5926:
-------------------------------------------
This jira has the odd side-effect of printing out a lot of garbage when running
in standalone and killing it with -9, gist of it being:
{noformat}
2012-11-29 13:08:27,227 WARN
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper: Possibly transient
ZooKeeper exception:
org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode =
ConnectionLoss for /hbase/master
2012-11-29 13:08:27,227 ERROR
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper: ZooKeeper getData
failed after 0 retries
2012-11-29 13:08:27,227 WARN org.apache.hadoop.hbase.zookeeper.ZKUtil: clean
znode for master Unable to get data of znode /hbase/master
org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode =
ConnectionLoss for /hbase/master
at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
at org.apache.zookeeper.ZooKeeper.getData(ZooKeeper.java:1131)
at
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.getData(RecoverableZooKeeper.java:291)
at
org.apache.hadoop.hbase.zookeeper.ZKUtil.getDataNoWatch(ZKUtil.java:562)
at
org.apache.hadoop.hbase.zookeeper.MasterAddressTracker.deleteIfEquals(MasterAddressTracker.java:168)
at org.apache.hadoop.hbase.ZNodeClearer.clear(ZNodeClearer.java:150)
at
org.apache.hadoop.hbase.master.HMasterCommandLine.run(HMasterCommandLine.java:110)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:65)
at
org.apache.hadoop.hbase.util.ServerCommandLine.doMain(ServerCommandLine.java:78)
at org.apache.hadoop.hbase.master.HMaster.main(HMaster.java:2298)
{noformat}
Basically the znode cleaner fails hard because ZK is offline.
I was confused to see more logs being printed out after running the kill.
> Delete the master znode after a master crash
> --------------------------------------------
>
> Key: HBASE-5926
> URL: https://issues.apache.org/jira/browse/HBASE-5926
> Project: HBase
> Issue Type: Improvement
> Components: master, scripts
> Affects Versions: 0.96.0
> Reporter: nkeywal
> Assignee: nkeywal
> Priority: Minor
> Fix For: 0.96.0
>
> Attachments: 5926.v10.patch, 5926.v11.patch, 5926.v13.patch,
> 5926.v14.patch, 5926.v6.patch, 5926.v8.patch, 5926.v9.patch
>
>
> This is the continuation of the work done in HBASE-5844.
> But we can't apply exactly the same strategy: for the region server, there is
> a znode per region server, while for the master & backup master there is a
> single znode for both.
> So if we apply the same strategy as for a regionserver, we may have this
> scenario:
> 1) Master starts
> 2) Backup master starts
> 3) Master dies
> 4) ZK detects it
> 5) Backup master receives the update from ZK
> 6) Backup master creates the new master node and become the main master
> 7) Previous master script continues
> 8) Previous master script deletes the master node in ZK
> 9) => issue: we deleted the node just created by the new master
> This should not happen often (usually the znode will be deleted soon enough),
> but it can happen.
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