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https://issues.apache.org/jira/browse/YARN-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15123110#comment-15123110
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Naganarasimha G R commented on YARN-3945:
-----------------------------------------
Hi [~wangda],
Few doubts here
bq. However, I don't want to add flexibility to AM resource limit. the hard
limit of queue's AM resource usage should be queueConfiguredResource *
am-percent.
So in this case, {{queueConfiguredResource}} is currently been calculated
{{queue's abscapacity * partition resource}}, so based on this there will be no
elasticity even though the resources are free in some other queue, is this
expected ? Are we trying to avoid elasticity because we try to avoid preempting
AM's even when preemption is enabled?
{code}
maxUserAMLimit = min{queue-am-limit * min{ULF, 1},
max{queue-am-limit / #activeUsers,
queue-am-limit * ULP}}
{code}
This in my opinion will control the am's launched by different users within a
queue, which is similar to the calculation of {{userlimit}}.
If its not possible to change because {{am-limit consistently change}} issue
then would it be better to leave it as it is with wrong calculation or consider
{{maxUserAMLimit = queueConfiguredResource * am-percent}}, thoughts ?
> maxApplicationsPerUser is wrongly calculated
> --------------------------------------------
>
> Key: YARN-3945
> URL: https://issues.apache.org/jira/browse/YARN-3945
> Project: Hadoop YARN
> Issue Type: Bug
> Components: capacityscheduler
> Affects Versions: 2.7.1
> Reporter: Naganarasimha G R
> Assignee: Naganarasimha G R
> Attachments: YARN-3945.20150728-1.patch, YARN-3945.20150729-1.patch,
> YARN-3945.V1.003.patch
>
>
> maxApplicationsPerUser is currently calculated based on the formula
> {{maxApplicationsPerUser = (int)(maxApplications * (userLimit / 100.0f) *
> userLimitFactor)}} but description of userlimit is
> {quote}
> Each queue enforces a limit on the percentage of resources allocated to a
> user at any given time, if there is demand for resources. The user limit can
> vary between a minimum and maximum value.{color:red} The the former (the
> minimum value) is set to this property value {color} and the latter (the
> maximum value) depends on the number of users who have submitted
> applications. For e.g., suppose the value of this property is 25. If two
> users have submitted applications to a queue, no single user can use more
> than 50% of the queue resources. If a third user submits an application, no
> single user can use more than 33% of the queue resources. With 4 or more
> users, no user can use more than 25% of the queues resources. A value of 100
> implies no user limits are imposed. The default is 100. Value is specified as
> a integer.
> {quote}
> configuration related to minimum limit should not be made used in a formula
> to calculate max applications for a user
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