Hmmm, okay.  I know it's running CDH4 4.4.0, as but for whether it was 
specifically configured with MR1 or MR2 (is there a distinction between MR2 and 
Yarn?) I'm not absolutely certain.  I know that the cluster "behaves" like the 
MR1 clusters I've worked with for years (I interact with the job tracker in a 
classical way for example).  Can I tell whether it's MR1 or MR2 from the job 
tracker or namename web UIs?

Thanks.

On Jan 29, 2014, at 00:52 , Harsh J wrote:

> Is your cluster running MR1 or MR2? On MR1, the CapacityScheduler
> would allow you to do this if you used appropriate memory based
> requests (see http://search-hadoop.com/m/gnFs91yIg1e), and on MR2
> (depending on the YARN scheduler resource request limits config) you
> can request your job be run with the maximum-most requests that would
> soak up all provided resources (of CPU and Memory) of a node such that
> only one container runs on a host at any given time.
> 
> On Wed, Jan 29, 2014 at 3:30 AM, Keith Wiley <[email protected]> wrote:
>> I'm running a program which in the streaming layer automatically 
>> multithreads and does so by automatically detecting the number of cores on 
>> the machine.  I realize this model is somewhat in conflict with Hadoop, but 
>> nonetheless, that's what I'm doing.  Thus, for even resource utilization, it 
>> would be nice to not only assign one mapper per core, but only one mapper 
>> per machine.  I realize that if I saturate the cluster none of this really 
>> matters, but consider the following example for clarity: 4-core nodes, 
>> 10-node cluster, thus 40 slots, fully configured across mappers and reducers 
>> (40 slots of each).  Say I run this program with just two mappers.  It would 
>> run much more efficiently (in essentially half the time) if I could force 
>> the two mappers to go to slots on two separate machines instead of running 
>> the risk that Hadoop may assign them both to the same machine.
>> 
>> Can this be done?
>> 
>> Thanks.


________________________________________________________________________________
Keith Wiley     [email protected]     keithwiley.com    music.keithwiley.com

"I used to be with it, but then they changed what it was.  Now, what I'm with
isn't it, and what's it seems weird and scary to me."
                                           --  Abe (Grandpa) Simpson
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