does not work under cgroup v2

[Ryutaroh Matsumoto]

When one gives "systemd.unified_cgroup_hierarchy=1" to the kernel command line,
only cgroup v2 is activated. Under such a situation we do not have
/sys/fs/cgroup/freezer

snap run hello-world just gives
cannot open cgroup hierarchy /sys/fs/cgroup/freezer: No such file or directory

No snap package seems usable. The above behavior is observed in Debian snap
package 2.40-1.

Ryutaroh Matsumoto

[Ryutaroh Matsumoto (emojifreak)]

This report duplicates
https://bugs.launchpad.net/snapd/+bug/1801664

Fedora will change its default to the unified cgroup hierarchy
from Fedora 31. Snap is expected to become unusable in Fedora 31
https://fedoraproject.org/wiki/Changes/CGroupsV2

[Maciej Borzecki (maciek-borzecki)]

The master branch contains some fixes that should make snaps work with cgroupsv2. Not all problems have been addressed yet, however the apps should not fail outright.

The 2.41 package available in Fedora carries this fix as a distro patch. With the upcoming 2.42 relase, no distro patches will be necessary.