[
https://issues.apache.org/jira/browse/MAPREDUCE-2694?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Arun C Murthy resolved MAPREDUCE-2694.
--------------------------------------
Resolution: Not A Problem
I thought more about this... I've spent time on this in the beginning and I
don't think a delta protocol is appropriate - particularly since the RM and AM
aren't 'in sync' ever.
Yes, this could lead to some waste, but the system is eventually consistent.
> AM releases too many containers due to the protocol
> ---------------------------------------------------
>
> Key: MAPREDUCE-2694
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-2694
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: mrv2
> Reporter: Arun C Murthy
> Assignee: Arun C Murthy
>
> - AM sends request asking 4 containers on host H1.
> - Asynchronously, host H1 reaches RM and gets assigned 4 containers. RM at
> this point, sets the value against H1 to
> zero in its aggregate request-table for all apps.
> - In the mean-while AM gets to need 3 more containers, so a total of 7
> including the 4 from previous request.
> - Today, AM sends the absolute number of 7 against H1 to RM as part of its
> request table.
> - RM seems to be overriding its earlier value of zero against H1 to 7 against
> H1. And thus allocating 7 more
> containers.
> - AM already gets 4 in this scheduling iteration, but gets 7 more, a total of
> 11 instead of the required 7.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
