[HTCondor-users] cgroups2 aka unified cgroups

[Bert DeKnuydt <Bert.Deknuydt@xxxxxxxxxxxxxxxx>]

Hi Condorants,

Since Fedora 31, by default, cgroups2 "unified cgroups" are used.  It's much nicer interface
compared to the old cgroups; (old is relative: cgroups2 dates from 2014).

Condor cannot deal with this and spits out the below lines (and then continues without e.g.
limiting memory usage);

---
01/28/20 09:39:36 (pid:448982) Cgroup controller for I/O statistics is not available.
01/28/20 09:39:36 (pid:448982) Cgroup controller for process management is not available.
01/28/20 09:39:36 (pid:448982) Cgroup controller for CPU accounting is not available.
01/28/20 09:39:36 (pid:448982) Cgroup controller for memory accounting is not available.
01/28/20 09:39:36 (pid:448982) Cgroup controller for CPU is not available.
01/28/20 09:39:36 (pid:448982) Unable to set memory limit because cgroup is invalid.
01/28/20 09:39:36 (pid:448982) Unable to set memsw limit because cgroup is invalid.
01/28/20 09:39:36 (pid:448982) Unable to set memory limit because cgroup is invalid.
01/28/20 09:39:36 (pid:448982) Unable to set memory limit because cgroup is invalid.
01/28/20 09:39:36 (pid:448982) Unable to set memsw limit because cgroup is invalid.
01/28/20 09:39:36 (pid:448982) Unable to set CPU shares because cgroup is invalid.
---

Currently, the workaround I know of, is to boot with flags 'systemd.unified_cgroup_hierarchy=0',
but that is not really nice, and will break other container stuff.

Are there any plans/WIP to add code for cgroups2? Better workarounds / tricks?

Greetings, B.