[slurm-users] License management and invoking scontrol in the prolog

[Davide DelVento]

Hi,

I would like to soft-enforce license utilization only when the -L is
set. My idea: check in the prolog if the license was requested and
only if it were, set the environmental variables needed for the
license.

I looked at all environmental variables set by slurm and did not find
any related to the license as I was hoping.

As a workaround, I could check

scontrol show job $SLURM_JOB_ID | grep License

and that would work, but (as discussed in other messages in this list)
the documentation at https://slurm.schedmd.com/prolog_epilog.html say

> Prolog and Epilog scripts should be designed to be as short as possible
> and should not call Slurm commands (e.g. squeue, scontrol, sacctmgr,
> etc). [...] Slurm commands in these scripts can potentially lead to performance
> issues and should not be used.

This is a bit of a concern, since the prolog would be invoked for
every job on the cluster, and it's a prolog (rather than the epilogue
like discussed in earlier messages).

So two questions:

1) is there a better workaround to check in the prolog if the current
job requested a license and/or
2) would this kind of use of scontrol be okay or is indeed a concern

Thanks!