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MapReduce, mail # user - Distribution of native executables and data for YARN-based execution


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RE: Distribution of native executables and data for YARN-based execution
John Lilley 2013-05-17, 17:15
Vinod,
Your first two items are spot on.  We don't expect to have the cluster to ourselves.  We also expect to interop with existing HDFS data and want to schedule for data locality.
John
From: Vinod Kumar Vavilapalli [mailto:[EMAIL PROTECTED]]
Sent: Friday, May 17, 2013 11:08 AM
To: [EMAIL PROTECTED]
Subject: Re: Distribution of native executables and data for YARN-based execution
I have a little bit of conflict of interest given I worked on Hadoop YARN all time but..

I have worked on torque/condor based resource management systems too. There are many advantages of working on top of YARN, a couple that should be specifically relevant here:
 - MR and non MR all on same cluster (there are a few not-so-ready MR implementations on existing schedulers but with lots of limitations)
 - Data locality feature that is native in Hadoop YARN and hard to simulate in other schedulers (we have experience trying this in the past)
 - Elastic resource managements - jobs can grow and shrink elastically

Thanks,
+Vinod Kumar Vavilapalli
Hortonworks Inc.
http://hortonworks.com/

On May 17, 2013, at 7:20 AM, Tim St Clair wrote:
Hi John -

If you are doing extensive levels of non-MR C-style batch, you may be better served to look at myriad universes of existing schedulers (torque, condor, etc.).  Or investigate the space around interop (1 cluster, many schedulers).

Either way, I recommend minimizing your dependency graph on your C-application where possible if you are working in a heterogeneous environment.

Cheers,
Tim
________________________________
From: "John Lilley" <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>>
To: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>
Sent: Friday, May 17, 2013 8:35:53 AM
Subject: RE: Distribution of native executables and data for YARN-based execution

Thanks!  This sounds exactly like what I need.  PUBLIC is right.

Do you know if this works for executables as well?  Like, would there be any issue transferring the executable bit on the file?

john

From: Vinod Kumar Vavilapalli [mailto:[EMAIL PROTECTED]]
Sent: Friday, May 17, 2013 12:56 AM
To: [EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>
Subject: Re: Distribution of native executables and data for YARN-based execution
The "local resources" you mentioned is the exact solution for this. For each LocalResource, you also mention a LocalResourceVisibility which takes one of the three values today - PUBLIC, PRIVATE and APPLICATON.

PUBLIC resources are downloaded only once and shared by any application running on that node.

PRIVATE resources are downloaded only once and shared by any application run by the same user on that node

APPLICATION resources are downloaded per application and removed after the application finishes.

Seems like you want PUBLIC or PRIVATE.

Note that for PUBLIC resources to work, the corresponding files need to be public on HDFS too.

Also if the remote files on HDFS are updated, these local files will be uploaded afresh again on each node where your containers run.

HTH

Thanks,
+Vinod Kumar Vavilapalli
Hortonworks Inc.
http://hortonworks.com/
On May 16, 2013, at 2:21 PM, John Lilley wrote:

I am attempting to distribute the execution of a C-based program onto a Hadoop cluster, without using MapReduce.  I read that YARN can be used to schedule non-MapReduce applications by programming to the ASM/RM interfaces.  As I understand it, eventually I get down to specifying each sub-task via ContainerLaunchContext.setCommands().

However, the program and shared libraries need to be stored on each worker's local disk to run.  In addition there is a hefty data set that the application uses (say, 4GB) that is accessed via regular open()/read() calls by a library.  I thought a decent strategy would be to push the program+data package to a known folder in HDFS, then launch a "bootstrap" that compared the HDFS folder version to a local folder, copying any updated files as needed before launching the native application task.

Are there better approaches?  I notice that one can implicitly copy "local resources" as part of the launch, but I don't want to copy 4GB every time, only occasionally when the application or reference data is updated.  Also, will my bootstrapper be allowed to set executable-mode bits on the programs after they are copied?

Thanks
John