CODEWITHSUNDEEP
distributed-computingcondor
mfmz
mfmz

Reputation: 227

How to force condor to submit job to all nodes in the cluster?

I have a condor cluster with multiple nodes active.

But when I submit a job, it only runs on a single node (i.e Master node). I'm aware that Condor automatically distributes job based on available resources.

But what if I want to force condor to make use of all the nodes? Just for the sake of evaluating process time when running on multiple nodes vs single node?

I have tried adding requirements = Machine == "hostname1" && Machine == "hostname2" in the submit file, but isn't working.

Upvotes: 1

Views: 1707

Answers (3)

fpierfed
fpierfed

Reputation: 71

I am afraid that I not fully understanding what you are asking. Let's see if I can help somehow. I can see a few scenarios:

  1. Condor is only scheduling your jobs to run on the master node, regardless of how many machines are available.
  2. Condor is scheduling jobs on all available machines. However what you are trying to do is get a particular job to make use of more than one machine.

In case 1. something fishy is going on with either your submit file or your pool setup. I will assume that condor_status returns more than one machine and that your pool setup is OK. The typical gotcha in this case is the following: if you do not specify a Requirement for your job, Condor will insert one for you. By default Condor will request that job runs on a machine that has the same OS and architecture of the submit node. This one did bite me a few times with heterogeneous pools ;-)

In case 2. you will have to make sure that your executable can make use of multiple machines (e.g. by way of MPI) and you need to tell Condor about it. One way to do that is to use the Parallel universe. Another way is to use a classic master/worker architecture where the workers are persistent Condor jobs.

Upvotes: 1

Louis Marascio
Louis Marascio

Reputation: 2679

Depending on what you're trying to do, you might want to use the parallel universe as outlined here: http://research.cs.wisc.edu/htcondor/manual/current/2_9Parallel_Applications.html

With a parallel universe job you indicate the machine count via machine_count and only need to queue a single task.

Upvotes: 1

Markus
Markus

Reputation: 773

Condor is limited in a way that it can only execute (system()) a command. If your program does not create many subtasks, you will not experience any speed improvement.

Please post a short snippet of your job description (file).

Upvotes: 0

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