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https://issues.apache.org/jira/browse/YARN-11622?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18024836#comment-18024836
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ASF GitHub Bot commented on YARN-11622:
---------------------------------------
github-actions[bot] commented on PR #6352:
URL: https://github.com/apache/hadoop/pull/6352#issuecomment-3369555480
We're closing this stale PR because it has been open for 100 days with no
activity. This isn't a judgement on the merit of the PR in any way. It's just a
way of keeping the PR queue manageable.
If you feel like this was a mistake, or you would like to continue working
on it, please feel free to re-open it and ask for a committer to remove the
stale tag and review again.
Thanks all for your contribution.
> ResourceManager asynchronous switch from Standy to Active exception
> -------------------------------------------------------------------
>
> Key: YARN-11622
> URL: https://issues.apache.org/jira/browse/YARN-11622
> Project: Hadoop YARN
> Issue Type: Bug
> Components: resourcemanager
> Affects Versions: 3.0.0-alpha4, 3.1.1, 3.3.0
> Reporter: wangzhihui
> Assignee: wangzhihui
> Priority: Major
> Labels: pull-request-available
> Attachments: rm_ha_solution.png, yuque_diagram (1).jpg,
> yuque_diagram.jpg
>
>
> h1. Two exception cases：
> h2. The first case：
> *The exception desc:*
> {code:java}
> 14:52:57,426 FATAL event.AsyncDispatcher (AsyncDispatcher.java:dispatch(203))
> - Error in dispatcher thread
> java.lang.NullPointerException
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager$RMActiveServices.access$1200(ResourceManager.java:610)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.handleTransitionToStandByInNewThread(ResourceManager.java:941)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.access$1100(ResourceManager.java:144)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager$RMFatalEventDispatcher.handle(ResourceManager.java:902)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ResourceManager$RMFatalEventDispatcher.handle(ResourceManager.java:892)
> at
> org.apache.hadoop.yarn.event.AsyncDispatcher.dispatch(AsyncDispatcher.java:197)
> at
> org.apache.hadoop.yarn.event.AsyncDispatcher$1.run(AsyncDispatcher.java:126)
> at java.lang.Thread.run(Thread.java:748){{}} * {code}
>
> * ActiveStandbyElector and ZKRMStateStore triggered toStandy event at
> 14:52:57,
> Two asynchronous events are respectively referred to as Thread_ 1、Thread_ 2.
> * As shown in the following figure， Thread_1 during the toStandby process ，
> reinitializes the activeServices to null. At this point, Thread_2 will use
> the "activeServices" when executing the handleTransitionToStandByInNewThread
> method ultimately resulting in a NullPointerException and the Reosurcemanager
> server exit.
> !yuque_diagram.jpg|width=629,height=100!
> h2. The second case：
> *The exception desc:*
> {code:java}
> 06:17:35,913 WARN ha.ActiveStandbyElector
> (ActiveStandbyElector.java:becomeActive(900)) - Exception handling the
> winning of election
> org.apache.hadoop.ha.ServiceFailedException: RM could not transition to Active
> at
> org.apache.hadoop.yarn.server.resourcemanager.ActiveStandbyElectorBasedElectorService.becomeActive(ActiveStandbyElectorBasedElectorService.java:146)
> at
> org.apache.hadoop.ha.ActiveStandbyElector.becomeActive(ActiveStandbyElector.java:896)
> at
> org.apache.hadoop.ha.ActiveStandbyElector.processResult(ActiveStandbyElector.java:543)
> at
> org.apache.zookeeper.ClientCnxn$EventThread.processEvent(ClientCnxn.java:558)
> at org.apache.zookeeper.ClientCnxn$EventThread.run(ClientCnxn.java:510)
> Caused by: org.apache.hadoop.ha.ServiceFailedException: Error on refreshAll
> during transition to Active
> at
> org.apache.hadoop.yarn.server.resourcemanager.AdminService.transitionToActive(AdminService.java:315)
> at
> org.apache.hadoop.yarn.server.resourcemanager.ActiveStandbyElectorBasedElectorService.becomeActive(ActiveStandbyElectorBasedElectorService.java:144)
> ... 4 more
> Caused by: org.apache.hadoop.ha.ServiceFailedException: RefreshAll operation
> failed
> at
> org.apache.hadoop.yarn.server.resourcemanager.AdminService.refreshAll(AdminService.java:765)
> at
> org.apache.hadoop.yarn.server.resourcemanager.AdminService.transitionToActive(AdminService.java:307)
> ... 5 more
> Caused by: java.lang.NullPointerException
> at
> org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler.reinitialize(CapacityScheduler.java:467)
> at
> org.apache.hadoop.yarn.server.resourcemanager.AdminService.refreshQueues(AdminService.java:423)
> at
> org.apache.hadoop.yarn.server.resourcemanager.AdminService.refreshAll(AdminService.java:754)
> ... 6 more
> 06:17:35,917 ERROR resourcemanager.ResourceManager
> (ResourceManager.java:handle(898)) - Received RMFatalEvent of type
> TRANSITION_TO_ACTIVE_FAILED, caused by failure to refresh configuration
> settings: org.apache.hadoop.ha.ServiceFailedException: RefreshAll opera
> tion failed{{}} {code}
> * ActiveStandbyElector and ZKRMStateStore triggered toActive event and
> toStandby event at 06:17:35, Two asynchronous events are respectively
> referred to as Thread_ 1、Thread_ 2.
> * During the execution of Thread_ 1 the CapacityScheduler.reinitialize is
> called to refresh the Scheduler configuration. At this time, the
> csConfProvider property of the CapacityScheduler is not initialized and its
> value is null. As a result. when the reinitialize method is executed
> csConfProvider is used, triggering a NullPointerException and causing Thread_
> 1 transition to active fail.
> !yuque_diagram (1).jpg|width=568,height=155!
> h1. Solution
> Due to the limited scope of lock control in ResourceMmanger’s
> transitionToActive and transitionToStandby methods, different events
> triggered asynchronously outside this lock scope can influence each other,
> leading to unpredictable issues. The proposed solution is to encapsulate
> different asynchronous tasks as TransitionToActiveStandbyRunner and enqueue
> them in a queue to be executed in order by a SingleThreadExecutor. This
> approach resolves the asynchronous problem and provides clearer and more
> controllable switching of to active and standby processes.
> !rm_ha_solution.png|width=362,height=353!
> h2. TransitionToActiveStandbyRunner and Subclasses
> h3. TransitionToActiveStandbyRunner
> TransitionToActiveStandbyRunner is a template class where the logic for
> different scenarios is placed and executed within the doTransaction method.
> {code:java}
> public abstract class TransitionToActiveStandbyRunner implements
> Callable<TransitionToActiveStandbyResult> { @Override
> public TransitionToActiveStandbyResult call() throws Exception {
> ... before log ...
> TransitionToActiveStandbyResult result = doTransaction();
> ... after log ...
> return result;
> } public abstract TransitionToActiveStandbyResult
> doTransaction();}{code}
> h3. Subclasses
> *AdminServiceToActiveRunner*
> AdminServiceToActiveRunner encapsulates the logic of the transitionToActive
> method in AdminService, handling the requests from clients and
> ActiveStandbyElector to transition to the active state.
> *AdminServiceToStandbyRunner*
> AdminServiceToStandbyRunner encapsulates the logic of the transitionToStandby
> method in AdminService, handling the requests from clients and
> ActiveStandbyElector to transition to the standby state.
> *RmStartAndStopToStandby*
> RmStartAndStopToStandby is used for transitioning the ResourceManager service
> to standby when it is stopping or starting
>
> *RMStartToActiveRunner*
> RMStartToActiveRunner is used for transitioning the ResourceManager service
> to active when it is stopping.
>
> *RMFatalToStandbyRunner*
> RMFatalToStandbyRunner is used to handle RMFatalEvent during Yarn open HA
> mode for transitioning to standby.
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