Podman troubleshooting

Error: OCI runtime error: crun: writing file `/sys/fs/cgroup/cgroup.subtree_control` invalid argument

cgroup2 doesn't yet support realtime-processes.
maybe we downgrade to the original cgroup?

In your Linux kernel configuration kernel parameters/options, set

systemd.unified_cgroup_hierarchy=0  # .. or 1 actually? just changed and works now

Issue/Cause:

• https://github.com/containers/crun/issues/704
• https://github.com/lxc/lxc/issues/3545
• https://bugs.archlinux.org/task/71560

Earlier workarounds

Temp Workaround 1:
sc --user stop mpd.service, then podman, then can start mpd (or start as non realtime service).
This worked initially but no longer.

Temp Workaround 2:
Assign the Linux kernel configuration following kernel params:
NOTE: grub abstracts kernel params? these params are not available.

systemd.unified_cgroup_hierarchy=1
cgroup_enable=cpu cgroup_enable=cpuset cgroup_enable=memory cgroup_memory=1

Error: kernel does not support overlay fs: 'overlay' is not supported over extfs at "/var/lib/containers/storage/overlay": backing file system is unsupported for this graph driver

See https://github.com/containers/podman/issues/1516

just reboot.