CS Technical FAQ

A version of the OpenPBS scheduler is installed on the cluster which allows you to submit jobs to the queue so that you don"t need to ssh to nodes individually to run jobs.

The easiest way to submit a job is to pass a shell script to the "qsub" command. The shell script can setup variables for you to define the number of nodes/processors you would like, etc. You can also have the scheduler email you when your job is started and completed amongst other options.

Here is an example script:

#!/bin/csh
#PBS -N Hello_waste
#PBS -l nodes=5:ppn=2
#PBS -l walltime=02:00
#PBS -m be
#
echo "The nodefile is ${PBS_NODEFILE} and it contains:"
cat ${PBS_NODEFILE}
echo ""

setenv LAMRSH ssh

lamboot $PBS_NODEFILE
mpirun C /cluster/home/sheltren/hello_waster
lamhalt

In this example, five nodes are being requested with two processors per node (#PBS -l nodes=5:ppn=2). "hello_waster" is a program compiled with mpicc. The environment variable, $PBS_NODEFILE, gets set automatically and has a list of all the nodes that PBS has reserved for your job.

To submit this script to the scheduler (assuming the script is named jobscript.csh), you can use the command:
$ qsub jobscript.csh

See the qsub manpage for more info.