* WORK IN PROGRESS *

Condor can help manage GPUs (graphics processing units) in your pool of execute nodes, making them available to jobs that can use them using an API like {link:http://www.khronos.org/opencl/ OpenCL} or {link:http://www.nvidia.com/object/cuda_home_new.html CUDA}.

Condor matches execute nodes (described by ClassAds) to jobs (also described by ClassAds). The general technique to manage GPUs is:

1. Advertise the GPU: Configure Condor so that execute nodes include information about available GPUs in their ClassAd.
2. Require a GPU: Jobs modify their Requirements to require a suitable GPU
3. Identify the GPU: Jobs modify their arguments or environment to learn which GPU it may use.

{section: Advertising the GPU}

You have several options for advertising your GPUs.  In increasing order of complexity they are:

1: Static configuration
2: Automatic configuration
3: Dynamic configuration

This progression may be a useful way to do initial setup and testing.  Start with a static configuration to ensure everything works.  Move to an automatic configuration to develop and test partial automation.  Finally a few small changes should make it possible to turn your automatic configuration into a dynamic configuration.

{subsection: Static configuration}

If you have a small number of nodes, or perhaps a large number
of identical nodes, you can add static attributes manually using
{link:http://www.cs.wisc.edu/condor/manual/v7.6/3_3Configuration.html#16198 STARTD_ATTRS}. In the simplest case, it might just be:

{code}
HAS_GPU=TRUE
STARTD_ATTRS=HAS_GPU
{endcode}

Or you could give lots of information about the GPUs, and even
have slot-specific information.  For an extended example, see
Carsten's post.


2. You can write a program to automatically write your
configuration file.  This is still using STARTD_ATTRS, but scales
better.  This is actually how Carsten's configuration works; he
has some example code at the above link.


3. You can have Condor automatically run a program you provide to
learn about the GPUs.  This is the "Daemon ClassAd Hooks",
previous known as HawkEye and Condor Cron.
http://www.cs.wisc.edu/condor/manual/v7.6/4_4Hooks.html#sec:daemon-classad-hooks
This is the route taken by the condorgpu project you found.
Converting Carsten's scripts to work this way would be pretty
easy.


{section: Credits}

Several examples were drawn from {link: https://lists.cs.wisc.edu/archive/condor-users/2011-March/msg00121.shtml Carsten Aulbert's post "RFC: Adding GPUs into Condor"} sent to the {link: http://www.cs.wisc.edu/condor/mail-lists/ condor-users} mailing list on March 25th, 2011.