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

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
>