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https://issues.apache.org/jira/browse/YARN-3020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14271729#comment-14271729
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Peter D Kirchner commented on YARN-3020:
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Hi thank you for your comment.  I believe your test works because it does all 
addContainerRequest()s between two heartbeats, before any interaction with the 
server on the accumulated requests.  If you insert a Thread.sleep() of more 
than the heartbeat interval in your test loop, allocate() is called in between 
your requests, and you should get O(n2) containers for your n requests.

> 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 1+2+3+...+n containers = n*(n+1)/2 .
> 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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