[slurm-users] Problem with cgroup plugin in Ubuntu22.04 and slurm 21.08.5

[Angel de Vicente]

Hello,

Angel de Vicente <angel.de.vicente at iac.es> writes:

> Do you know how I could fix this while keeping the cgroup plugin? My
> intuition tells me that I should probably get the latest version of
> Slurm and compile it myself, but I thought I would ask here before going
> that route.

I followed my intuition and got much closer to fixing it.

So far I learned the following:

+ the older Slurm seems to only support cgroup v1
+ Ubuntu 18.04 seems to be in a "Hybrid" cgroup mode
+ Ubuntu 22.04 is in "V2" mode:

So, I compiled in Ubuntu 22.04 a newer Slurm version (22.05.8), which
has support for both cgroup v1 and v2.

But when starting this version, slurmd complains with:

,----
| slurmd: fatal: Hybrid mode is not supported. Mounted cgroups are: 
| 5:freezer:/
| 3:cpuacct:/
`----

If I unmount /cgroup/freezer and /cgroup/cpuacct then all works fine
with Slurm, but I'm not sure where/who is mounting these, and whether it
is safe to unmount them. These machines were being upgraded from 18.04,
so not sure if these are leftovers from that version or a completely new
22.04 installation would also have these.

Cheers,
-- 
Ángel de Vicente
 Research Software Engineer (Supercomputing and BigData)
 Tel.: +34 922-605-747
 Web.: http://research.iac.es/proyecto/polmag/

 GPG: 0x8BDC390B69033F52
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