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From Arun C Murthy <...@hortonworks.com>
Subject Re: Yarn related questions:
Date Fri, 06 Jan 2012 18:42:32 GMT
Please don't hijack threads, start a new one. Thanks.

On Jan 6, 2012, at 10:41 AM, Arun C Murthy wrote:

> You're probably hitting MAPREDUCE-3537. Try using the hadoop-0.23.1-SNAPSHOT or build
it yourself from branch-0.23 on ASF svn.
> Arun
> On Jan 5, 2012, at 10:45 PM, raghavendhra rahul wrote:
>> 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 node
>> 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.RawLocalFileSystem.getFileStatus(RawLocalFileSystem.java:431)
>>         at org.apache.hadoop.fs.FileSystem.primitiveMkdir(FileSystem.java:815)
>>         at org.apache.hadoop.fs.DelegateToFileSystem.mkdir(DelegateToFileSystem.java:143)
>>         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$4.next(FileContext.java:697)
>>         at org.apache.hadoop.fs.FileContext$FSLinkResolver.resolve(FileContext.java:2325)
>>         at org.apache.hadoop.fs.FileContext.mkdir(FileContext.java:697)
>>         at org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor.launchContainer(DefaultContainerExecutor.java:122)
>>         at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:237)
>>         at org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch.call(ContainerLaunch.java:67)
>>         at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
>>         at java.util.concurrent.FutureTask.run(FutureTask.java:166)
>>         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
>>         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
>>         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
>>> 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,
>>> 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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