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https://issues.apache.org/jira/browse/HBASE-16008?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15346920#comment-15346920
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Enis Soztutar commented on HBASE-16008:
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bq. And All tools which need disable one switch can't be run simultaneously?
This maybe one problem some day.
I was suggesting (offline) that instead of having a single znode, we can have a
parent znode, and every tool instance that needs the master to be in
maintenance mode will create a child znode there. As long as there is at least
one child znode, the master remains in maintenance mode. Kind of a reference
count mechanism. We can use this to implement a manual switch as well, by
having a non-ephemeral znode written for the switch.
> A robust way deal with early termination of HBCK
> ------------------------------------------------
>
> Key: HBASE-16008
> URL: https://issues.apache.org/jira/browse/HBASE-16008
> Project: HBase
> Issue Type: Improvement
> Components: hbck
> Reporter: Stephen Yuan Jiang
> Assignee: Stephen Yuan Jiang
>
> When HBCK is running, we want to disable Catalog Janitor, Balancer and
> Split/Merge. Today, the implementation is not robust. If HBCK is terminated
> earlier by Control-C, the changed state would not be reset to original.
> HBASE-15406 was trying to solve this problem for Split/Merge switch. The
> implementation is complicated, and it did not solve CJ and Balancer.
> We also have another problem is that to prevent multiple HBCK run, we used a
> file lock to indicate a running HBCK; earlier terminating might not clean up
> the file. Sometimes we have to manually remove the file so that future HBCK
> could run.
> The proposal to solve all the problem is to use a znode to indicate that one
> HBCK is running. CJ, balancer, and Split/Merge switch all look for this
> znode before doing it operation.
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