suja s created HDFS-3561:
----------------------------
Summary: ZKFC retries for 45 times to connect to other NN during
fencing when network between NNs broken and standby Nn will not take over as
active
Key: HDFS-3561
URL: https://issues.apache.org/jira/browse/HDFS-3561
Project: Hadoop HDFS
Issue Type: Bug
Components: auto-failover
Reporter: suja s
Scenario:
Active NN on machine1
Standby NN on machine2
Machine1 is isolated from the network (machine1 network cable unplugged)
After zk session timeout ZKFC at machine2 side gets notification that NN1 is
not there.
ZKFC tries to failover NN2 as active.
As part of this during fencing it tries to connect to machine1 and kill NN1.
(sshfence technique configured)
This connection retry happens for 45 times( as it takes
ipc.client.connect.max.socket.retries)
Also after that standby NN is not able to take over as active (because of
fencing failure).
Suggestion: If ZKFC is not able to reach other NN for specified time/no of
retries it can consider that NN as dead and instruct the other NN to take over
as active as there is no chance of the other NN (NN1) retaining its state as
active after zk session timeout when its isolated from network
>From ZKFC log:
{noformat}
2012-06-21 17:46:14,378 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 22 time(s).
2012-06-21 17:46:35,378 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 23 time(s).
2012-06-21 17:46:56,378 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 24 time(s).
2012-06-21 17:47:17,378 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 25 time(s).
2012-06-21 17:47:38,382 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 26 time(s).
2012-06-21 17:47:59,382 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 27 time(s).
2012-06-21 17:48:20,386 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 28 time(s).
2012-06-21 17:48:41,386 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 29 time(s).
2012-06-21 17:49:02,386 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 30 time(s).
2012-06-21 17:49:23,386 INFO org.apache.hadoop.ipc.Client: Retrying connect to
server: HOST-xx-xx-xx-102/xx.xx.xx.102:65110. Already tried 31 time(s).
{noformat}
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