Mailing-List: contact yarn-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Date: Wed, 6 Sep 2017 01:16:02 +0000 (UTC)
From: "Steven Rand (JIRA)" <jira@apache.org>
To: yarn-issues@hadoop.apache.org
Message-ID: <JIRA.13092704.1501990619000.34984.1504660562419@Atlassian.JIRA>
In-Reply-To: <JIRA.13092704.1501990619000@Atlassian.JIRA>
References: <JIRA.13092704.1501990619000@Atlassian.JIRA> <JIRA.13092704.1501990619948@jira-lw-us.apache.org>
Subject: [jira] [Commented] (YARN-6956) preemption may only consider
 resource requests for one node
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
archived-at: Wed, 06 Sep 2017 01:16:09 -0000


    [ https://issues.apache.org/jira/browse/YARN-6956?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16154671#comment-16154671 ] 

Steven Rand commented on YARN-6956:
-----------------------------------

Friendly ping [~kasha] and/or [~templedf]. I'll fix the checkstyle issues in the next patch, but wanted to gather other feedback as well.

> preemption may only consider resource requests for one node
> -----------------------------------------------------------
>
>                 Key: YARN-6956
>                 URL: https://issues.apache.org/jira/browse/YARN-6956
>             Project: Hadoop YARN
>          Issue Type: Bug
>          Components: fairscheduler
>    Affects Versions: 2.9.0, 3.0.0-beta1
>         Environment: CDH 5.11.0
>            Reporter: Steven Rand
>            Assignee: Steven Rand
>         Attachments: YARN-6956.001.patch
>
>
> I'm observing the following series of events on a CDH 5.11.0 cluster, which seem to be possible after YARN-6163:
> 1. An application is considered to be starved, so {{FSPreemptionThread}} calls {{identifyContainersToPreempt}}, and that calls {{FSAppAttempt#getStarvedResourceRequests}} to get a list of {{ResourceRequest}} instances that are enough to address the app's starvation.
> 2. The first {{ResourceRequest}} that {{getStarvedResourceRequests}} sees is enough to address the app's starvation, so we break out of the loop over {{appSchedulingInfo.getAllResourceRequests()}} after only one iteration: https://github.com/apache/hadoop/blob/trunk/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSAppAttempt.java#L1180. We return only this one {{ResourceRequest}} back to the {{identifyContainersToPreempt}} method.
> 3. It turns out that this particular {{ResourceRequest}} happens to have a value for {{getResourceName}} that identifies a specific node in the cluster. This causes preemption to only consider containers on that node, and not the rest of the cluster.
> [~kasha], does that make sense? I'm happy to submit a patch if I'm understanding the problem correctly.


--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

---------------------------------------------------------------------
To unsubscribe, e-mail: yarn-issues-unsubscribe@hadoop.apache.org
For additional commands, e-mail: yarn-issues-help@hadoop.apache.org