[
https://issues.apache.org/jira/browse/YARN-45?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13628625#comment-13628625
]
Carlo Curino commented on YARN-45:
----------------------------------
Agreed.
As for #1, your previous comments made us indeed "simplify" #1 as follows:
We inform the AM that a Set<ContainerID> will be killed unless he preempts them
(the exact same containers). We dropped the "trading these containers for
equivalent ones" as we agreed with your comments that would be too funky.
The rationale behind including this simple container-based preemption is
twofold:
a) it matches very well with what the FairScheduler does today (we simply
provide a cheaper form of preemption w.r.t. the straight-up kill it used to
do), and
b) it allows for compact bookkeeping for "kill if no preemption happens" in a
policy we wrote to add preemption to the CapacityScheduler which seems to
behave well.
As for #2 I totally agree this is important to have, and it has lots of
potential since it empowers the AM to make smart local decisions (it is well
aligned with the overall spirit of Yarn I think).
We will handle this both in the RM and AM in future patches. Where "future" =
we have the code, but need a polish before posting.
Cheers,
Carlo
> Scheduler feedback to AM to release containers
> ----------------------------------------------
>
> Key: YARN-45
> URL: https://issues.apache.org/jira/browse/YARN-45
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: resourcemanager
> Reporter: Chris Douglas
> Assignee: Carlo Curino
> Attachments: YARN-45.patch
>
>
> The ResourceManager strikes a balance between cluster utilization and strict
> enforcement of resource invariants in the cluster. Individual allocations of
> containers must be reclaimed- or reserved- to restore the global invariants
> when cluster load shifts. In some cases, the ApplicationMaster can respond to
> fluctuations in resource availability without losing the work already
> completed by that task (MAPREDUCE-4584). Supplying it with this information
> would be helpful for overall cluster utilization [1]. To this end, we want to
> establish a protocol for the RM to ask the AM to release containers.
> [1] http://research.yahoo.com/files/yl-2012-003.pdf
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
