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https://issues.apache.org/jira/browse/AMBARI-18728?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yusaku Sako updated AMBARI-18728:
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Reporter: Vivek Rathod (was: Andrew Onischuk)
> During cluster install, Components get timed out icon while starting
> --------------------------------------------------------------------
>
> Key: AMBARI-18728
> URL: https://issues.apache.org/jira/browse/AMBARI-18728
> Project: Ambari
> Issue Type: Bug
> Reporter: Vivek Rathod
> Assignee: Andrew Onischuk
> Fix For: 2.5.0
>
> Attachments: AMBARI-18728.patch
>
>
> This was caused by a very tricky race-condition in the way python
> multiprocessing.thread works resulting in deadlock in
> ambari_agent.ActionQueue thread.
> The problem is the below flow:
> If this all these three get executed at the same time (a very rear occasion):
> 1. Process1 executes queue.get(False)
> 2. Process2 executes queue.put(largeObjectWhichTakesLongTimeToPut)
> 3. Someone kills Process2.
> This results in deadlock in process1 get. Which is caused by queue
> locks/semaphores to being released during put of process2.
> I have wrote a script test_race_condition.py to emulate this behaviour and
> indeed could reproduce this and test the fix for it.
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