[jira] [Updated] (YARN-4610) Reservations continue looking for one app causes other apps to starve

["Jason Lowe (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/YARN-4610?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jason Lowe updated YARN-4610:
-----------------------------
    Attachment: YARN-4610.001.patch

Patch that resets the amount needed to unreserve at the beginning of canAssignToUser.  That way subsequent users in the loop will not accidentally inherit a previous user's amount.

A potential workaround until this appears in a release is to set yarn.scheduler.capacity.reservations-continue-look-all-nodes to false in capacity-scheduler.xml.  Note that this property is refreshable via yarn rmadmin -refreshQueues, so changing it does not require a restart.  After this fix the property should be restored to true to avoid the original issue fixed in YARN-3434.

> Reservations continue looking for one app causes other apps to starve
> ---------------------------------------------------------------------
>
>                 Key: YARN-4610
>                 URL: https://issues.apache.org/jira/browse/YARN-4610
>             Project: Hadoop YARN
>          Issue Type: Bug
>          Components: capacityscheduler
>    Affects Versions: 2.7.1
>            Reporter: Jason Lowe
>            Assignee: Jason Lowe
>            Priority: Blocker
>         Attachments: YARN-4610.001.patch
>
>
> CapacityScheduler's LeafQueue has "reservations continue looking" logic that allows an application to unreserve elsewhere to fulfil a container request on a node that has available space.  However in 2.7 that logic seems to break allocations for subsequent apps in the queue.  Once a user hits its user limit, subsequent apps in the queue for other users receive containers at a significantly reduced rate.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)