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https://issues.apache.org/jira/browse/AMBARI-15364?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15188519#comment-15188519
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Sumit Mohanty commented on AMBARI-15364:
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"Rebalance HDFS" is a good reference.
> Ability to trigger NameNode checkpoint from Ambari Web
> ------------------------------------------------------
>
> Key: AMBARI-15364
> URL: https://issues.apache.org/jira/browse/AMBARI-15364
> Project: Ambari
> Issue Type: Bug
> Affects Versions: 2.2.0
> Reporter: Sumit Mohanty
> Fix For: 2.4.0
>
> Attachments: Screen Shot 2016-03-09 at 6.18.28 PM.png
>
>
> Expose the checkpoint action in the UI and make it work E2E (and ability to
> check on progress):
> Services > HDFS > Service Actions > Save Namespace
> Ample documentation is available that describe checkpoint process for HDFS.
> Roughly, this translate to
> {code}
> >> hdfs dfsadmin -safemode enter
> Safe mode is ON
> >> hdfs dfsadmin -saveNamespace
> Save namespace successful
> >> hdfs dfsadmin -safemode leave
> Safe mode is OFF
> {code}
> One approach is to have custom commands for each operation. In general,
> having support to get into and out of SAFEMODE is useful.
> saveNamespace may be a long running command. Therefore custom command for
> this operation may be long running and thus there is a chance of timeout or
> may even block execution of other commands on the NN host. So the better
> approach would be to design a custom command that can start "saveNamespace",
> check the status, and if needed kill the command.
>
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