[
https://issues.apache.org/jira/browse/HDFS-6827?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14103278#comment-14103278
]
Zesheng Wu commented on HDFS-6827:
----------------------------------
bq. As I described in the issue description, our NN came up inside about 6
seconds. 1 second for Client#handleConnectionFailure() sleep, the other 5
seconds for some unknown reasons, maybe GC or network problems, we haven't
found direct evidences.
Sorry, this description is not very accurate.
Our NN came up inside about 6 seconds. And the ZKFC retried connection exactly
after NN starting successfully. There are about 6 seconds between ZKFC detected
'Connection reset by peer' and reconnected NN successfully. 1 second for
{{Client#handleConnectionFailure()}} sleep is definitely, the other 5 seconds
for some unknown reasons, maybe GC or network problems, we haven't found direct
evidences.
> Both NameNodes stuck in STANDBY state due to HealthMonitor not aware of the
> target's status changing sometimes
> --------------------------------------------------------------------------------------------------------------
>
> Key: HDFS-6827
> URL: https://issues.apache.org/jira/browse/HDFS-6827
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: ha
> Affects Versions: 2.4.1
> Reporter: Zesheng Wu
> Assignee: Zesheng Wu
> Priority: Critical
> Attachments: HDFS-6827.1.patch
>
>
> In our production cluster, we encounter a scenario like this: ANN crashed due
> to write journal timeout, and was restarted by the watchdog automatically,
> but after restarting both of the NNs are standby.
> Following is the logs of the scenario:
> # NN1 is down due to write journal timeout:
> {color:red}2014-08-03,23:02:02,219{color} INFO
> org.apache.hadoop.hdfs.server.namenode.NameNode: SHUTDOWN_MSG
> # ZKFC1 detected "connection reset by peer"
> {color:red}2014-08-03,23:02:02,560{color} ERROR
> org.apache.hadoop.security.UserGroupInformation: PriviledgedActionException
> as:xx@xx.HADOOP (auth:KERBEROS) cause:java.io.IOException:
> {color:red}Connection reset by peer{color}
> # NN1 wat restarted successfully by the watchdog:
> 2014-08-03,23:02:07,884 INFO org.apache.hadoop.hdfs.server.namenode.NameNode:
> Web-server up at: xx:13201
> 2014-08-03,23:02:07,884 INFO org.apache.hadoop.ipc.Server: IPC Server
> Responder: starting
> {color:red}2014-08-03,23:02:07,884{color} INFO org.apache.hadoop.ipc.Server:
> IPC Server listener on 13200: starting
> 2014-08-03,23:02:08,742 INFO org.apache.hadoop.ipc.Server: RPC server clean
> thread started!
> 2014-08-03,23:02:08,743 INFO org.apache.hadoop.hdfs.server.namenode.NameNode:
> Registered DFSClientInformation MBean
> 2014-08-03,23:02:08,744 INFO org.apache.hadoop.hdfs.server.namenode.NameNode:
> NameNode up at: xx/xx:13200
> 2014-08-03,23:02:08,744 INFO
> org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Starting services
> required for standby state
> # ZKFC1 retried the connection and considered NN1 was healthy
> {color:red}2014-08-03,23:02:08,292{color} INFO org.apache.hadoop.ipc.Client:
> Retrying connect to server: xx/xx:13200. Already tried 0 time(s); retry
> policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=1, sleepTime=1
> SECONDS)
> # ZKFC1 still considered NN1 as a healthy Active NN, and didn't trigger the
> failover, as a result, both NNs were standby.
> The root cause of this bug is that NN is restarted too quickly and ZKFC
> health monitor doesn't realize that.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
