Comment # 1 on bug 1202821 from Michal Koutn���

(In reply to Fabian Vogt from comment #0)
> On openqaworker1, there are four (pretty much identical) containers set up
> as services which run openQA tests.

What does it mean containers as services? (I assume it's from project [1],
right?)

Q1) Is there difference how the containers are started among the four? (I.e.
from user session vs from a systemd service.)

> Sometimes a container has a different issue regarding cgroups, where it
> looks like the assigned cgroup somehow disappeared.

What do you mean here? Is it the system.slice vs machine.slice discrepancy? Or
anything else?

> openqaworker1:~ # podman exec -i openqaworker1_container_102 su -P
> su: failed to create pseudo-terminal: Operation not permitted

This looks suspiciously similar to the bug 1178775, if it weren't Leap 15.4
with systemd v249 (where this should be fixed).

> openqaworker1:~ # podman exec -i openqaworker1_container_103 su -P
> Error: exec failed: unable to start container process: error adding pid
> 10265 to cgroups: failed to write 10265: openat2

If it was process 10625 terminated earlier than it could have been migrated to
scope cgroup, we'd get ESRCH. This is ENOENT, so the cgroup doesn't exist. So
the *c1c0.scope doesn't exist from systemd's PoV.

> It's visible that in the case of container 102, the device cgroup entries "b
> *:* m" and "c *:* m" got removed
> somehow and for container 103, the cgroup changed completely
> (system.slice/*.service instead of machine.slice/libpod-*).

Q2) What cgroup "driver" does podman use for these containers? (cgroupManager
in podman lingo, cgroupfs vs systemd.)

> bug 1178775 sounds similar. I guess systemd is somehow interfering with
> podman?

Or podman is interfering with systemd. :-)

1) 

Q3) Would it be too bold to ask to switch the host to the unified mode
(system.cgroup_unified_hierarchy=1 to kernel cmdline)?
  (Issues with device controller and maintaining parallel hierarchies with
systemd (and container runtime) would likely be gone with just the unified
hierarchy.)


[1] https://github.com/openSUSE/containers-systemd.