[slurm-users] SLURM reservations with MAGNETIC flag

[Bas van der Vlies]

The problem has been solved. We tested it with ’srun’ and that did not work the same is for ’salloc’  To make it work with these commands apply one of the solutions:
 1.  Add ‘defer’ to ScheduleParameters
 2.  srun --begin=now+1


sbatch works out of the box.  Thanks to schedmd (Ben) for the solution, see:
 * https://bugs.schedmd.com/show_bug.cgi?id=12350

Regards

> On 7 Apr 2021, at 13:57, Bas van der Vlies <bas.vandervlies at surf.nl> wrote:
> 
> 
> 
> Still have this question. Sometime we have free nodes and users that are allowed to run in the MAGNETIC reservation are first scheduled on the free nodes instead of reservation nodes. Dit I forgot an option or is this the expected behavior?
> 
> On 25/09/2020 16:47, Bas van der Vlies wrote:
>> Are people using the MAGNETIC reservation flag? My question would be how? because to my it would be more useful if the reservation is tried first and then the free nodes.
>> That is what I expected with the MAGNETIC flag.
>> Bas van der Vlies
>> | Operations, Support & Development | SURFsara | Science Park 140 | 1098 XG  Amsterdam
>> | T +31 (0) 20 800 1300  | bas.vandervlies at surf.nl | www.surf.nl |
>>> On 24 Sep 2020, at 12:16, Bas van der Vlies <bas.vandervlies at surf.nl> wrote:
>>> 
>>> We have installed slurm 20.02.5 and I am trying to use this new reservation flag
>>> MAGNETIC:
>>>  * https://slurm.schedmd.com/reservations.html
>>> 
>>> From this page I understand that the job will land in the reservation even if we
>>> did not specify the
>>> reservation name.  I tested it on our cluster setup but it does not seems to
>>> work as expected
>>> 
>>> I create a reservation for 1 node for user bas with flag magnetic. I submit a
>>> job and to my surprise the job is scheduled on a free node and not on the node
>>> in the reservation. It is only scheduled in the reservation if all nodes are
>>> occupied. Is this the default behaviour or did a miss a setting?
>>> 
>>> I have set all available nodes offline except the reservation node and then I
>>> see this:
>>> ```
>>> bas at batch2:~/src$ srun -N1 --pty /bin/bash
>>> srun: Required node not available (down, drained or reserved)
>>> srun: job 1713 queued and waiting for resources
>>> srun: job 1713 has been allocated resources
>>> ```
>>> 
>>> From this I see that the "magentic" reservation is considered as last.
>>> 
>>> 
>>> regards
>>> 
>>> -- 
>>> --
>>> Bas van der Vlies
>>> | Operations, Support & Development | SURF | Science Park 140 | 1098 XG
>>> Amsterdam
>>> | T +31 (0) 20 800 1300 | bas.vandervlies at surf.nl | www.surf.nl
> 
> -- 
> Bas van der Vlies
> | HPCV Supercomputing | Internal Services  | SURF | https://userinfo.surfsara.nl |
> | Science Park 140 | 1098 XG Amsterdam | Phone: +31208001300 |
> |  bas.vandervlies at surf.nl