[slurm-users] Job Step Resource Requests are Ignored

[Chris Samuel]

On Tuesday, 5 May 2020 11:00:27 PM PDT Maria Semple wrote:

> Is there no way to achieve what I want then? I'd like the first and last job
> steps to always be able to run, even if the second step needs too many
> resources (based on the cluster).

That should just work.

#!/bin/bash
#SBATCH -c 2
#SBATCH -n 1

srun -c 1 echo hello
srun -c 4 echo big wide
srun -c 1 echo world

gives:

hello
srun: Job step's --cpus-per-task value exceeds that of job (4 > 2). Job step 
may never run.
srun: error: Unable to create step for job 604659: More processors requested 
than permitted
world

> As a side note, do you know why it's not even possible to restrict the
> number of resources a single step uses (i.e. set less CPUs than are
> available to the full job)?

My suspicion is that you've not set up Slurm to use cgroups to restrict the 
resources a job can use to just those requested.

https://slurm.schedmd.com/cgroups.html

All the best,
Chris
-- 
  Chris Samuel  :  http://www.csamuel.org/  :  Berkeley, CA, USA