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https://issues.apache.org/jira/browse/YARN-4080?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14720538#comment-14720538
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Subru Krishnan commented on YARN-4080:
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[~mding], your proposal looks interesting and thanks for taking a look at
YARN-1051. You are right that the main use case of the reservation system is to
address SLAs but it can be used for capacity planning for long running services
by specifying start time as now and deadline as infinity. This should provide
more predictability for long running services as you can handle dynamic
resource requirements of a service as YARN-1051 allows expressing time varying
capacity. Additionally in combination with YARN-2877, you should be able to
achieve the dynamic host based reservation mechanics you have proposed.
> Capacity planning for long running services on YARN
> ---------------------------------------------------
>
> Key: YARN-4080
> URL: https://issues.apache.org/jira/browse/YARN-4080
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: api, resourcemanager
> Reporter: MENG DING
>
> YARN-1197 addresses the functionality of container resource resize. One major
> use case of this feature is for long running services managed by Slider to
> dynamically flex up and down resource allocation of individual components
> (e.g., HBase region server), based on application metrics/alerts obtained
> through third-party monitoring and policy engine.
> One key issue with increasing container resource at any point of time is that
> the additional resource needed by the application component may not be
> available *on the specific node*. In this case, we need to rely on preemption
> logic to reclaim the required resource back from other (preemptable)
> applications running on the same node. But this may not be possible today
> because:
> * preemption doesn't consider constraints of pending resource requests, such
> as hard locality requirements, user limits, etc (being addressed in YARN-2154
> and possibly in YARN-3769?)
> * there may not be any preemptable container available due to the fact that
> no queue is over its guaranteed capacity.
> What we need, ideally, is a way for YARN to support future capacity planning
> of long running services. At the minimum, we need to provide a way to let
> YARN know about the resource usage prediction/pattern of a long running
> service. And given this knowledge, YARN should be able to preempt resources
> from other applications to accommodate the resource needs of the long running
> service.
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