Examples of Jobs on Quest
Additional details and examples of Quest job submission scripts and commands.
See Research Computing's GitHub repository of example jobs for language/software specific examples and scripts you can copy and modify.
Interactive Jobs
Example: Interactive Job with More than One Node
If you submit an interactive job requiring more than one node, you will land on the Head Node for your job once the scheduler finds the resources. For more information see Submitting an Interactive Job.
[abc123@quser22 ~]$ srun -A p12345 -p normal -N 2 --tasks-per-node=10 --mem-per-cpu=1G --time=01:00:00 --pty bash -l ---------------------------------------- srun job start: Thu Feb 28 16:31:27 CST 2019 Job ID: 557781 Username: abc123 Queue: normal Account: p12345 ---------------------------------------- The following variables are not guaranteed to be the same in prologue and the job run script ---------------------------------------- PATH (in prologue) : /hpc/slurm/usertools:/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/sbin:/usr/lpp/mmfs/bin:/opt/ibutils/bin:/home/abc123/bin WORKDIR is: /home/abc123 ---------------------------------------- [abc123@qnode4217 ~]$
This interactive job requests 2 nodes and 10 cores in each of those nodes. In total you will have access to 20 cores. Since the job reserved 1 GB per core, 20 GB of RAM is allocated in total (i.e. 10 GB in each node).
To find the name of the other compute node(s) that you have been assigned as part of your job, you can use the squeue command in a from the same terminal session. Look under NODELIST in the squeue output:
[abc123@qnode4217 ~]$ squeue JOBID PARTITION NAME USER ST TIME NODES NODELIST(REASON) 557781 normal bash abc123 R 5:51 2 qnode[4217-4218]
You can then ssh to the other node(s) if needed as long as your job is active.
ssh qnode4218
Batch Jobs
Job Array
Job arrays can be used to submit multiple jobs at once that use the same application script. This can be useful if you want to run the same script multiple times with different input parameters.
In the example below, the --array option defines the job array, with a specification of the index numbers you want to use (in this case, 0 through 9). The $SLURM_ARRAY_TASK_ID bash environmental variable takes on the value of the job array index for each job (so here, integer values 0 through 9, one value for each job). In this example, the value of $SLURM_ARRAY_TASK_ID is used to select the correct index from the input_args bash array which was constructed by reading in input_args.txt, each row of which is then passed on to a script as command line arguments.
jobsubmission.sh
#!/bin/bash
#SBATCH --account=w10001 ## YOUR ACCOUNT pXXXX or bXXXX
#SBATCH --partition=w10001 ### PARTITION (buyin, short, normal, w10001, etc)
#SBATCH --array=0-9 ## number of jobs to run "in parallel"
#SBATCH --nodes=1 ## how many computers do you need
#SBATCH --ntasks-per-node=1 ## how many cpus or processors do you need on each computer
#SBATCH --time=00:10:00 ## how long does this need to run (remember different partitions have restrictions on this param)
#SBATCH --mem-per-cpu=1G ## how much RAM do you need per CPU (this effects your FairShare score so be careful to not ask for more than you need))
#SBATCH --job-name="sample_job_\${SLURM_ARRAY_TASK_ID}" ## use the task id in the name of the job
#SBATCH --output=sample_job.%A_%a.out ## use the jobid (A) and the specific job index (a) to name your log file
#SBATCH --mail-type=ALL ## you can receive e-mail alerts from SLURM when your job begins and when your job finishes (completed, failed, etc)
#SBATCH --mail-user=email@u.northwestern.edu ## your email
module purge all
module load python-anaconda3
source activate /projects/intro/envs/slurm-py37-test
IFS=$'\n' read -d '' -r -a input_args < input_args.txt
python slurm_test.py --filename ${input_args[$SLURM_ARRAY_TASK_ID]}where input_args.txt contains the following:
input_args.txt
filename1.txt filename2.txt filename3.txt filename4.txt filename5.txt filename6.txt filename7.txt filename8.txt filename9.txt filename10.txt
and myscript.py contains the following code:
myscript.py
import argparse
import time
def parse_commandline():
"""Parse the arguments given on the command-line.
"""
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument("--filename",
help="Name of file",
default=None)
args = parser.parse_args()
return args
###############################################################################
# BEGIN MAIN FUNCTION
###############################################################################
if __name__ == '__main__':
args = parse_commandline()
#time.sleep(10) # Sleep for 3 seconds
print(args.filename)In this example, myscript.py will receive the values in input.csv as arguments: the first field will be sys.argv[1], the second field will be sys.argv[2], etc.
Note: make sure the number you specify for the --array parameter matches the number of lines in your input file!
Also, note that in this example standard output and error files are printed separately for each element of the job array with the --output and --error options. To avoid each element overwriting these files, tag them with jobID (%A) and elementID (%a) variables (which are automatically assigned by the scheduler) so elements have their own distinct output and error files.
Submit this script with:
sbatch jobsubmission.sh
The job array will then be submitted to the scheduler.
Dependent Jobs
Dependent jobs are a series of jobs which run or wait to run conditional on the state of another job. For instance, you may submit two jobs and you want the first job to complete successfully before the second job runs. In order to submit this type of workflow, you pass sbatch the jobid of the job that needs to finish before this job starts via the command line argument:
--dependency=afterok:<jobid>
To accomplish this, it is helpful to write all of your sbatch commands in bash script. You will notice that anything you can tell slurm via #SBATCH in the submission script itself, you can also pass to sbatch via the command line. The key here is that the bash variable jid0, jid1, jid2 will contain the jobid that SLURM assigns after you run the sbatch command.
wrapper_script.sh
#!/bin/bash
jid0=($(sbatch --time=00:10:00 --account=w10001 --partition=w10001 --nodes=1 --ntasks-per-node=1 --mem=8G --job-name=example --output=job_%A.out example_submit.sh))
echo "jid0 ${jid0[-1]}" >> slurm_ids
jid1=($(sbatch --dependency=afterok:${jid0[-1]} --time=00:10:00 --account=w10001 --partition=w10001 --nodes=1 --ntasks-per-node=1 --mem=8G --job-name=example --output=job_%A.out --export=DEPENDENTJOB=${jid0[-1]} example_submit.sh))
echo "jid1 ${jid1[-1]}" >> slurm_ids
jid2=($(sbatch --dependency=afterok:${jid1[-1]} --time=00:10:00 --account=w10001 --partition=w10001 --nodes=1 --ntasks-per-node=1 --mem=8G --job-name=example --output=job_%A.out --export=DEPENDENTJOB=${jid1[-1]} example_submit.sh))
echo "jid2 ${jid2[-1]}" >> slurm_idsIn the above, the second job will not start until the first job is finished and the third job will not start until the second one is finished. The actual submission script that is being run is below.
example_submit.sh
#!/bin/bash
#SBATCH --mail-type=ALL ## you can receive e-mail alerts from SLURM when your job begins and when your job finishes (completed, failed, etc)
#SBATCH --mail-user=email@u.northwestern.edu ## your email
if [[ -z "${DEPENDENTJOB}" ]]; then
echo "First job in workflow"
else
echo "Job started after " $DEPENDENTJOB
fi
module purge all
module load python-anaconda3
source activate /projects/intro/envs/slurm-py37-test
python --version
python myscript.py --job-id $DEPENDENTJOBwhere myscript.py contains the following code:
myscript.py
import argparse
import time
def parse_commandline():
"""Parse the arguments given on the command-line.
"""
parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument("--job-id",
help="Job number",
default=0)
args = parser.parse_args()
return args
###############################################################################
# BEGIN MAIN FUNCTION
###############################################################################
if __name__ == '__main__':
args = parse_commandline()
time.sleep(3) # Sleep for 3 seconds
print(args.job_id)In this example, we print the job id that had to finish in order for the dependent job to begin. Therefore, the very first job should print 0 because it did not rely on any job to finish in order to run but the second job should print the jobid of the first job and so on.
bash wrapper_script.sh
This will submit the three jobs in sequence and you should see jobs 2 and 3 pending for reason DEPENDENCY.