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https://issues.apache.org/jira/browse/YARN-1954?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13973791#comment-13973791
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Zhijie Shen commented on YARN-1954:
-----------------------------------
Let me give an example:
On main non-daemon thread:
1. amRMClientAsync.registerApplicationMaster
2. while (tasks are not completed) sleep a while
3. amRMClientAsync.unregisterApplicationMaster
On daemon thread (such as AMRMClientAsync's callback thread):
1. mark tasks are completed in onShutdownRequest
In this case, I think we'd better not to ask users to write the loop (step 2 on
main thread). We provide the waitForCompletion method which take the user
defined checker (e.g. Supplier<Boolean>).
> Add waitFor to AMRMClient(Async)
> --------------------------------
>
> Key: YARN-1954
> URL: https://issues.apache.org/jira/browse/YARN-1954
> Project: Hadoop YARN
> Issue Type: New Feature
> Components: client
> Affects Versions: 3.0.0, 2.4.0
> Reporter: Zhijie Shen
> Assignee: Tsuyoshi OZAWA
>
> Recently, I saw some use cases of AMRMClient(Async). The painful thing is
> that the main non-daemon thread has to sit in a dummy loop to prevent AM
> process exiting before all the tasks are done, while unregistration is
> triggered on a separate another daemon thread by callback methods (in
> particular when using AMRMClientAsync). IMHO, it should be beneficial to add
> a waitFor method to AMRMClient(Async) to block the AM until unregistration or
> user supplied check point, such that users don't need to write the loop
> themselves.
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