[
https://issues.apache.org/jira/browse/YARN-4963?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15248176#comment-15248176
]
Wangda Tan commented on YARN-4963:
----------------------------------
[~nroberts],
{code}
So maybe there are two things to do:
1) Have the global OFF_SWITCH check to handle the simple case of avoiding too
many network-heavy applications on a node.
2) A feature where applications can specify a
max_containers_assigned_per_node_per_heartbeat. I think this would be checked
down in LeafQueue.assignContainers().
{code}
Make sense to me, I agree to limit the scope to OFF_SWITCH allocations in this
JIRA.
bq. Even i feel the same, any specfic reason it has been set only at the
scheduler level other than the AMRM interface change ? We can keep the default
value as 1 so that its still compatible. Also anyway allocation happens within
app's & queue's capacity limits so i feel it would be ideal for app to decide
how many allocations in off_switch node. thoughts ?
Beyond maximum off-switch allocation per node heartbeat, there're some other
scheduler global options we may need to consider to move to per-app. One
example is locality delays for different locality type.
> capacity scheduler: Make number of OFF_SWITCH assignments per heartbeat
> configurable
> ------------------------------------------------------------------------------------
>
> Key: YARN-4963
> URL: https://issues.apache.org/jira/browse/YARN-4963
> Project: Hadoop YARN
> Issue Type: Improvement
> Components: capacityscheduler
> Affects Versions: 3.0.0, 2.7.2
> Reporter: Nathan Roberts
> Assignee: Nathan Roberts
> Attachments: YARN-4963.001.patch
>
>
> Currently the capacity scheduler will allow exactly 1 OFF_SWITCH assignment
> per heartbeat. With more and more non MapReduce workloads coming along, the
> degree of locality is declining, causing scheduling to be significantly
> slower. It's still important to limit the number of OFF_SWITCH assignments to
> avoid densely packing OFF_SWITCH containers onto nodes.
> Proposal is to add a simple config that makes the number of OFF_SWITCH
> assignments configurable.
> Will upload candidate patch shortly.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
