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From raghavendhra rahul <raghavendhrara...@gmail.com>
Subject Re: Yarn related questions:
Date Fri, 06 Jan 2012 06:45:26 GMT
Yes i am writing my own application master.Is there a way to specify
node1: 10 conatiners
node2: 10 containers
Can we specify this kind of list using the application master????

Also i set request.setHostName("client"); where client is the hostname of a
I checked the log to find the following error
java.io.FileNotFoundException: File /local1/yarn/.yarn/local/
usercache/rahul_2011/appcache/application_1325760852770_0001 does not exist
        at org.apache.hadoop.fs.FilterFs.mkdir(FilterFs.java:189)
        at org.apache.hadoop.fs.FileContext$4.next(FileContext.java:700)
        at org.apache.hadoop.fs.FileContext$4.next(FileContext.java:697)
        at org.apache.hadoop.fs.FileContext.mkdir(FileContext.java:697)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at java.lang.Thread.run(Thread.java:636)

Any ideas.....

On Fri, Jan 6, 2012 at 12:41 AM, Arun C Murthy <acm@hortonworks.com> wrote:

> Are you writing your own application i.e. custom ApplicationMaster?
> You need to pass ResourceRequest (RR) with a valid hostname alongwith
> (optionally) RR with rack and also a mandatory RR with * as the
> resource-name.
> Arun
> On Jan 4, 2012, at 8:04 PM, raghavendhra rahul wrote:
> Hi,
> I tried to set the client node for launching the container within the
> application master.
> I have set the parameter as
> request.setHostName("client");
> but the containers are not launched in the destined host.Instead the loop
> goes on continuously.
> 2012-01-04 15:11:48,535 INFO appmaster.ApplicationMaster
> (ApplicationMaster.java:run(204)) - Current application state: loop=95,
> appDone=false, total=2, requested=2, completed=0, failed=0,
> currentAllocated=0
> On Wed, Jan 4, 2012 at 11:24 PM, Robert Evans <evans@yahoo-inc.com> wrote:
>>  Ann,
>> A container more or less corresponds to a task in MRV1.  There is one
>> exception to this, as the ApplicationMaster also runs in a container.  The
>> ApplicationMaster will request new containers for each mapper or reducer
>> task that it wants to launch.  There is separate code from the container
>> that will serve up the intermediate mapper output and is run as part of the
>> NodeManager (Similar to the TaskTracker from before).  When the
>> ApplicationMaster requests a container it also includes with it a hint as
>> to where it would like the container placed.  In fact it actually makes
>> three request one for the exact node, one for the rack the node is on, and
>> one that is generic and could be anywhere.  The scheduler will try to honor
>> those requests in the same order so data locality is still considered and
>> generally honored.  Yes there is the possibility of back and forth to get a
>> container, but the ApplicationMaster generally will try to use all of the
>> containers that it is given, even if they are not optimal.
>> --Bobby Evans
>> On 1/4/12 10:23 AM, "Ann Pal" <ann_r_pal@yahoo.com> wrote:
>> Hi,
>> I am trying to understand more about Hadoop Next Gen Map Reduce and had
>> the following questions based on the following post:
>> http://developer.yahoo.com/blogs/hadoop/posts/2011/03/mapreduce-nextgen-scheduler/
>> [1] How does application decide how many containers it needs? The
>> containers are used to store the intermediate result at the map nodes?
>> [2] During resource allocation, if the resource manager has no mapping
>> between map tasks to resources allocated, how can it properly allocate the
>> right resources. It might end up allocating resources on a node, which does
>> not have data for the map task, and hence is not optimal. In this case the
>> Application Master will have to reject it and request again . There could
>> be considerable back- and- forth between application master and resource
>> manager before it could converge. Is this right?
>> Thanks!

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