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https://issues.apache.org/jira/browse/HBASE-26977?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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LiangJun He resolved HBASE-26977.
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Resolution: Resolved
> HMaster's ShutdownHook does not take effect, if tablesOnMaster is false
> -----------------------------------------------------------------------
>
> Key: HBASE-26977
> URL: https://issues.apache.org/jira/browse/HBASE-26977
> Project: HBase
> Issue Type: Bug
> Components: master
> Affects Versions: 1.7.1, 2.4.9
> Reporter: LiangJun He
> Assignee: LiangJun He
> Priority: Major
> Attachments: image-2022-04-26-21-12-51-843.png,
> image-2022-04-26-21-18-24-884.png, image-2022-04-26-21-22-38-572.png
>
>
> Because we are going to upgrade the HBase kernel version, during the test, I
> found that the HMaster ShutdownHook of version 1.7.1 and 2.4.9 did not take
> effect if tablesOnMaster is false. After further confirmation, I found that
> all versions of HBase 1.x and 2.x have this problem.
> I analyzed the cause of the problem：
> Before HBase 3.x, HMaster registered ShutdownHook by calling the run() method
> of HRegionServer, but the run() method will be blocked on the
> waitForMasterActive() method of HMaster(before registering the shutdownhook)
> if tablesOnMaster is false. Eventually, the ShutdownHook of HMaster was not
> registered successfully.
> 1. The code path of HRegionServer's run() method：
> !image-2022-04-26-21-18-24-884.png!
>
> 2. The preRegistrationInitialization() method will be called first:
> !image-2022-04-26-21-12-51-843.png!
> 3. The HMaster's waitForMasterActive() method will be blocked if
> tablesOnMaster is false:
> !image-2022-04-26-21-22-38-572.png!
> Finally, because the default value of tablesOnMaster is false, the
> ShutdownHook of HMaster was not registered successfully.
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