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https://issues.apache.org/jira/browse/YARN-3945?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15093246#comment-15093246
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Wangda Tan commented on YARN-3945:
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Hi [~Naganarasimha],
I agree that fixing user limit is a non-trivial fix and should be done in a
separated JIRA.
Thinking hard of this issue, I feel maybe we shouldn't bother user-limit to
max-application too much:
- We have max-am-percent already, and CS respects it
- With above, maybe we don't have to limit number of applications per user, I
felt it's not that important.
- Two different dimensions of limitation (max-am-resource-per-user and
max-number-per-user) could lead to under utilization. (A user could use less AM
resource but cannot get new AM container allocated before app-number exceeds.
I would suggest to make a simple fix:
Now numAppsPerUser could be more than numAppsPerQueue (before of user-limit).
Same to user-resource and user-am-resource, it will be helpful to make sure
they're capped by queue's limitation (am-resource, number-am,
queue-max-resource, etc.).
With this user will not confused by web UI reports max resource of a user could
exceed max resource of a queue.
> 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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