[
https://issues.apache.org/jira/browse/YARN-3243?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14353704#comment-14353704
]
Jian He commented on YARN-3243:
-------------------------------
thanks Wangda !
- ParentQueue#canAssignToThisQueue,
{code}
if (totalUsedCapacityRatio >= maxAvailCapacity) {
canAssign = false;
break;
}
{code}
instead of comparing with ratio, I think it might be simpler to compare
resource value
> CapacityScheduler should pass headroom from parent to children to make sure
> ParentQueue obey its capacity limits.
> -----------------------------------------------------------------------------------------------------------------
>
> Key: YARN-3243
> URL: https://issues.apache.org/jira/browse/YARN-3243
> Project: Hadoop YARN
> Issue Type: Bug
> Components: capacityscheduler, resourcemanager
> Reporter: Wangda Tan
> Assignee: Wangda Tan
> Attachments: YARN-3243.1.patch
>
>
> Now CapacityScheduler has some issues to make sure ParentQueue always obeys
> its capacity limits, for example:
> 1) When allocating container of a parent queue, it will only check
> parentQueue.usage < parentQueue.max. If leaf queue allocated a container.size
> > (parentQueue.max - parentQueue.usage), parent queue can excess its max
> resource limit, as following example:
> {code}
> A (usage=54, max=55)
> / \
> A1 A2 (usage=1, max=55)
> (usage=53, max=53)
> {code}
> Queue-A2 is able to allocate container since its usage < max, but if we do
> that, A's usage can excess A.max.
> 2) When doing continous reservation check, parent queue will only tell
> children "you need unreserve *some* resource, so that I will less than my
> maximum resource", but it will not tell how many resource need to be
> unreserved. This may lead to parent queue excesses configured maximum
> capacity as well.
> With YARN-3099/YARN-3124, now we have {{ResourceUsage}} class in each class,
> *here is my proposal*:
> - ParentQueue will set its children's ResourceUsage.headroom, which means,
> *maximum resource its children can allocate*.
> - ParentQueue will set its children's headroom to be (saying parent's name is
> "qA"): min(qA.headroom, qA.max - qA.used). This will make sure qA's
> ancestors' capacity will be enforced as well (qA.headroom is set by qA's
> parent).
> - {{needToUnReserve}} is not necessary, instead, children can get how much
> resource need to be unreserved to keep its parent's resource limit.
> - More over, with this, YARN-3026 will make a clear boundary between
> LeafQueue and FiCaSchedulerApp, headroom will consider user-limit, etc.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
