cgroup-tools not compatible with cgroup2

[Joachim]

When launching cgroup commands like cgcreate after the upgrade to 21.10, the following error is printed:

cgcreate: libcgroup initialization failed: Cgroup is not mounted

The issue seems to be related to the libcgroup version, which does not support the now used cgroup2.

Expected behavior:
the cgroup-tools should be compatible with the cgroup version delivered with the distribution.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: cgroup-tools 0.41-11
ProcVersionSignature: Ubuntu 5.13.0-20.20-generic 5.13.14
Uname: Linux 5.13.0-20-generic x86_64
ApportVersion: 2.20.11-0ubuntu70
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
Date: Fri Oct 22 09:21:30 2021
InstallationDate: Installed on 2020-02-06 (623 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
SourcePackage: libcgroup
UpgradeStatus: Upgraded to impish on 2021-10-18 (3 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Oded Arbel (oded-geek)]

The problem is that impish is using cgroups v2, while the cgroup-tools is 0.41 (as shown in the report) which supports only cgroups v1.

As the problem is solved in jammy by using cgroup-tools 2.0, and impish will be out of support in a couple of months - I recommend closing this issue as "wont fix".

[brian mullan (bmullan)]

I found this BUG Post and it is related to a problem I was having with
Ubuntu 22.04 LTS

On systems I did a cold install of Ubuntu 22.04 LTS  on everything
including LXD worked  !

On 2 other systems which were running Ubuntu 20.04 LTS and on which LXD
worked great.

I upgraded using:

/$ sudo do-release-upgrade -d/

The upgrade was successful ... but ... LXD now had problems.

/I could create Ubuntu LXD containers but they would not "start"./

Finally, found that it was a CGROUP2 bug/problem so I disabled “cgroup2”
use on the HOST

The Work-around Solution was:

    add the following string to the |GRUB_CMDLINE_LINUX| line in
    |/etc/default/grub| and then run |sudo update-grub|.

    |*systemd.unified_cgroup_hierarchy**=**0* |

After a reboot of the Host the LXD Ubuntu Containers started up Okay again.

I don't know if this is the same bug or different but "cgroup2" was the
cause of the LXD failure to start up containers it had created.

Brian