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https://issues.apache.org/jira/browse/HADOOP-10251?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14582914#comment-14582914
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Vinayakumar B commented on HADOOP-10251:
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bq. 2015-06-12 02:26:02,608 ERROR org.apache.hadoop.ha.ZKFailoverController:
Local service NameNode at zdh196/10.43.156.196:9000 has changed the
serviceState to active. Expected was standby. Quitting election marking fencing
necessary.
bq. 2015-06-12 02:27:56,878 ERROR org.apache.hadoop.ha.ZKFailoverController:
Local service NameNode at zdh195/10.43.156.195:9000 has changed the
serviceState to active. Expected was standby. Quitting election marking fencing
necessary.
The use case mentioned is normal auto failover. Not the manual failover using
haadmin commands.
And I am seeing both NN1 and NN2 are not staying in Active mode if the
transition happens from standby->active. This is strange.
Can you check this ?
1. Stop both ZKFCs. and NNs.
2. Start only one ZKFC and NN. It should successfully convert to active and
check whether it is staying in ACTIVE for long time.
3. Attach the logs for ZKFC after restart, (logs from the restarted point, all
lines)
4. Also attach the ZKFailoverController.java source code you are using.
> Both NameNodes could be in STANDBY State if SNN network is unstable
> -------------------------------------------------------------------
>
> Key: HADOOP-10251
> URL: https://issues.apache.org/jira/browse/HADOOP-10251
> Project: Hadoop Common
> Issue Type: Bug
> Components: ha
> Affects Versions: 2.2.0
> Reporter: Vinayakumar B
> Assignee: Vinayakumar B
> Priority: Critical
> Fix For: 2.5.0
>
> Attachments: HADOOP-10251.patch, HADOOP-10251.patch,
> HADOOP-10251.patch, HADOOP-10251.patch, HADOOP-10251.patch
>
>
> Following corner scenario happened in one of our cluster.
> 1. NN1 was Active and NN2 was Standby
> 2. NN2 machine's network was slow
> 3. NN1 got shutdown.
> 4. NN2 ZKFC got the notification and trying to check for old active for
> fencing. (This took little more time, again due to slow network)
> 5. In between, NN1 got restarted by our automatic monitoring, and ZKFC made
> it Active.
> 6. Now NN2 ZKFC got Old Active as NN1 and it did graceful fencing of NN1 to
> STANBY.
> 7. Before writing ActiveBreadCrumb to ZK, NN2 ZKFC got session timeout and
> got shutdown before making NN2 Active.
> *Now cluster having both NameNodes as STANDBY.*
> NN1 ZKFC still thinks that its nameNode is in Active state.
> NN2 ZKFC waiting for election.
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