Re: [HTCondor-users] condor cgroup hierarchy wrt systemd managed slices

[Greg Thain <gthain@xxxxxxxxxxx>]

On 10/14/25 04:52, Thomas Hartmann wrote:
> Hi Greg,
>
> > This was true in cgroup v1, but not in v2. Why do you want to put 
> > the job hierarchy in a separate cgroup, is it to partition memory for 
> > the condor daemons?
>
> my main aim would be to squeeze in background/backfill jobs on our 
> cluster and probably use systemd for resource control of the slice(s)
>
> our user story:
> We had to drain/reboot our cluster a number of times over the last 
> month to apply new critical kernels. As the workloads of our user 
> groups are somewhat laggy wrt draining/the job run times, we have each 
> time during draining quite some wasted cycles as they are not idling 
> until the last jobs finally finishes.


Ah, I see! Perhaps an easier solution is to use the "-start 
<expresssion>" option to the condor_drain tool. This expression matches 
jobs that are allowed to start on a draining machine, but will be killed 
when the last job not of this type exits.

-greg