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MapReduce, mail # dev - ApplicationMaster and completed container status


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Re: ApplicationMaster and completed container status
Sharad Agarwal 2011-11-28, 05:36
primarily two reasons:

1. There is no recurring communication channel between NM and AM.

2. Application must act on single source of truth, which is RM.

Sharad

On Sun, Nov 27, 2011 at 9:01 PM, Praveen Sripati
<[EMAIL PROTECTED]>wrote:

> Hi,
>
> According to
>
>
> http://hadoop.apache.org/common/docs/r0.23.0/hadoop-yarn/hadoop-yarn-site/WritingYarnApplications.html
>
> >Completed containers: Once an ApplicationMaster triggers a launch an
> allocated container, it will receive an update from the ResourceManager
> when the container completes. The ApplicationMaster can look into the
> status of the completed container and take appropriate actions such as
> re-trying a particular sub-task in case of a failure.
>
> My understanding is NM sends the completed status of the containers to the
> RM and the RM in turn sends the status to AM. Why can't the NM send the
> status of the completed containers to the AM directly? The NM will anyway
> know which AM has requested for launching the containers.
>
> Thanks,
> Praveen
>