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https://issues.apache.org/jira/browse/AMBARI-19289?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15821926#comment-15821926
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Di Li commented on AMBARI-19289:
--------------------------------
pushed to trunk as
https://git-wip-us.apache.org/repos/asf?p=ambari.git;a=commit;h=fb50d88f182d02c36a27185142cab6c9e4b3659c
> HDFS Service check fails if previous active NN is down
> ------------------------------------------------------
>
> Key: AMBARI-19289
> URL: https://issues.apache.org/jira/browse/AMBARI-19289
> Project: Ambari
> Issue Type: Bug
> Components: ambari-server
> Affects Versions: 2.4.2
> Reporter: Weiwei Yang
> Assignee: Weiwei Yang
> Fix For: trunk
>
> Attachments: AMBARI-19289_branch-2.5.01.patch,
> AMBARI-19289_trunk.01.patch, AMBARI-19289_trunk.02.patch
>
>
> *Reproduce steps*
> # Enable namenode HA
> # Shutdown the active namenode, standby takes over
> # Run HDFS service check
> hdfs service check script uses
> {{hdfs dfsadmin -fs hdfs://mycluster -safemode get | grep OFF}}
> to check if namenode is out of safemode. However this command will fail if
> 1st NN is down without checking the state of 2nd NN. This is likely a HDFS
> bug similar to HDFS-8277.
> *Proposal*
> There are several approaches to fix this
> # Loop each namenode address and get safemode with {{hdfs dfsadmin -fs
> hdfs://nn_host:8020 -safemode get | grep OFF}}, as long as there is one NN
> returns OFF, consider DFS is not in safemode and continue the rest of check.
> However is it really necessary to add such complexity for service check?
> # Remove the safemode check code, if HDFS is in safemode, read/write
> operations will fail anyway so service check won't pass
> I am preferring to #2 because it makes script simpler and work in all cases.
> Note this is service check, it should pass as long as HDFS is in working
> state. It is not namenode check.
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