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https://issues.apache.org/jira/browse/YARN-3020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14285984#comment-14285984
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Wei Yan commented on YARN-3020:
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Hi, [~peterdkirchner], try to understand clearly your point. Given a case that
the client requests 10 containers, it is possible that the client sends 1
container request at heartbeat 1, and sends out 10 container requests at
heartbeat 2. So your concern is that the client requests 11 containers, instead
of the 10, right? Pls correct me if I misunderstood here.
For FairScheduler (I'm more familiar with FS), the late request will overwrite
the previous one, see AppSchedulingInfo.updateResourceRequests().
> n similar addContainerRequest()s produce n*(n+1)/2 containers
> -------------------------------------------------------------
>
> Key: YARN-3020
> URL: https://issues.apache.org/jira/browse/YARN-3020
> Project: Hadoop YARN
> Issue Type: Bug
> Components: client
> Affects Versions: 2.5.0, 2.6.0, 2.5.1, 2.5.2
> Reporter: Peter D Kirchner
> Original Estimate: 24h
> Remaining Estimate: 24h
>
> BUG: If the application master calls addContainerRequest() n times, but with
> the same priority, I get up to 1+2+3+...+n containers = n*(n+1)/2 . The most
> containers are requested when the interval between calls to
> addContainerRequest() exceeds the heartbeat interval of calls to allocate()
> (in AMRMClientImpl's run() method).
> If the application master calls addContainerRequest() n times, but with a
> unique priority each time, I get n containers (as I intended).
> Analysis:
> There is a logic problem in AMRMClientImpl.java.
> Although AMRMClientImpl.java, allocate() does an ask.clear() , on subsequent
> calls to addContainerRequest(), addResourceRequest() finds the previous
> matching remoteRequest and increments the container count rather than
> starting anew, and does an addResourceRequestToAsk() which defeats the
> ask.clear().
> From documentation and code comments, it was hard for me to discern the
> intended behavior of the API, but the inconsistency reported in this issue
> suggests one case or the other is implemented incorrectly.
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