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https://issues.apache.org/jira/browse/FLINK-18229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17497938#comment-17497938
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Xintong Song commented on FLINK-18229:
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Thanks for volunteering, [~huwh]. You are assigned.

> Pending worker requests should be properly cleared
> --------------------------------------------------
>
>                 Key: FLINK-18229
>                 URL: https://issues.apache.org/jira/browse/FLINK-18229
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Deployment / Kubernetes, Deployment / YARN, Runtime / 
> Coordination
>    Affects Versions: 1.9.3, 1.10.1, 1.11.0
>            Reporter: Xintong Song
>            Assignee: huweihua
>            Priority: Major
>             Fix For: 1.15.0
>
>
> Currently, if Kubernetes/Yarn does not have enough resources to fulfill 
> Flink's resource requirement, there will be pending pod/container requests on 
> Kubernetes/Yarn. These pending resource requirements are never cleared until 
> either fulfilled or the Flink cluster is shutdown.
> However, sometimes Flink no longer needs the pending resources. E.g., the 
> slot request is then fulfilled by another slots that become available, or the 
> job failed due to slot request timeout (in a session cluster). In such cases, 
> Flink does not remove the resource request until the resource is allocated, 
> then it discovers that it no longer needs the allocated resource and release 
> them. This would affect the underlying Kubernetes/Yarn cluster, especially 
> when the cluster is under heavy workload.
> It would be good for Flink to cancel pod/container requests as earlier as 
> possible if it can discover that some of the pending workers are no longer 
> needed.
> There are several approaches potentially achieve this.
>  # We can always check whether there's a pending worker that can be canceled 
> when a \{{PendingTaskManagerSlot}} is unassigned.
>  # We can have a separate timeout for requesting new worker. If the resource 
> cannot be allocated within the given time since requested, we should cancel 
> that resource request and claim a resource allocation failure.
>  # We can share the same timeout for starting new worker (proposed in 
> FLINK-13554). This is similar to 2), but it requires the worker to be 
> registered, rather than allocated, before timeout.



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