[jira] [Commented] (FLINK-5893) Race condition in removing previous JobManagerRegistration in ResourceManager

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-5893?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15880183#comment-15880183 ] 

ASF GitHub Bot commented on FLINK-5893:
---------------------------------------

GitHub user zhijiangW opened a pull request:

    https://github.com/apache/flink/pull/3399

    [FLINK-5893][ResourceManager]Fix the bug of race condition for removing previous JobManagerRegistration in ResourceManager

    The map of **JobManagerRegistration** in ResourceManager is not thread-safe, and currently there may be two threads to operate the map concurrently to bring unexpected results.
    
    The scenario is like this :
    
    - **registerJobManager**: When the job leader changes and the new JobManager leader registers to ResourceManager, the new **JobManagerRegistration** will replace the old one in the map with the same key **JobID**. This process is triggered by rpc thread.
    - Meanwhile, the **JobLeaderIdService** in ResourceManager could be aware of job leader change and trigger the action **jobLeaderLostLeadership** in another thread. In this action, it will remove the previous **JobManagerRegistration** from the map by **JobID**, but the old **JobManagerRegistration** may be already replaced by the new one from **registerJobManager**.
    
    In summary, this race condition may cause the new **JobManagerRegistration** removed from ResourceManager, resulting in exception when request slot from ResourceManager. It can occur in small probability when running JobManager failure ITCase.
    
    Consider the solution of this issue, the **jobLeaderLostLeadership** can be scheduled by **runAsync** in rpc thread.

You can merge this pull request into a Git repository by running:

    $ git pull https://github.com/zhijiangW/flink FLINK-5893

Alternatively you can review and apply these changes as the patch at:

    https://github.com/apache/flink/pull/3399.patch

To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:

    This closes #3399
    
----
commit 28e783821063509123c33db873e00755ebcbb561
Author: 淘江 <ta...@alibaba-inc.com>
Date:   2017-02-23T09:30:24Z

    [FLINK-5893][ResourceManager]Fix the bug of race condition for removing previous JobManagerRegistration in ResourceManager

----


> Race condition in removing previous JobManagerRegistration in ResourceManager
> -----------------------------------------------------------------------------
>
>                 Key: FLINK-5893
>                 URL: https://issues.apache.org/jira/browse/FLINK-5893
>             Project: Flink
>          Issue Type: Bug
>          Components: ResourceManager
>            Reporter: zhijiang
>            Assignee: zhijiang
>
> The map of {{JobManagerRegistration}} in ResourceManager is not thread-safe, and currently there may be two threads to operate the map concurrently to bring unexpected results.
> The scenario is like this :
>  - {{registerJobManager}}: When the job leader changes and the new JobManager leader registers to ResourceManager, the new {{JobManagerRegistration}} will replace the old one in the map with the same key {{JobID}}. This process is triggered by rpc thread.
>  - Meanwhile, the {{JobLeaderIdService}} in ResourceManager could be aware of job leader change and trigger the action {{jobLeaderLostLeadership}} in another thread. In this action, it will remove the previous {{JobManagerRegistration}} from the map by {{JobID}}, but the old {{JobManagerRegistration}} may be already replaced by the new one from {{registerJobManager}}.
> In summary, this race condition may cause the new {{JobManagerRegistration}} removed from ResourceManager, resulting in exception when request slot from ResourceManager. It can occur in small probability when running JobManager failure ITCase.
> Consider the solution of this issue, the {{jobLeaderLostLeadership}} can be scheduled by {{runAsync}} in rpc thread and no need to bring extra lock for the map.



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