[pkg-lxc-devel] Bug#944389: lxc: Fails to work with cgroupv2 / unified hierarchy

[Ryutaroh Matsumoto]

Package: lxc
Version: 1:3.1.0+really3.0.4-2
Followup-For: Bug #944389

With config lines:
lxc.cgroup.devices.deny =
lxc.cgroup.devices.allow =
lxc.init.cmd = /bin/bash

the container starts, but without lxc.init.cmd = /bin/bash
the /sbin/init in the container prints

Failed to mount cgroup at /sys/fs/cgroup/systemd: Operation not permitted
[!!!!!!] Failed to mount API filesystems.

and does not start, when host Debian started with systemd.unified_cgroup_hierarchy.

There seems to be some compatibility issue between lxc and systemd in
the container.

Best regards,
Ryutaroh



-- System Information:
Debian Release: 10.1
  APT prefers stable
  APT policy: (990, 'stable'), (500, 'stable-updates'), (500, 'unstable'), (500, 'testing'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 5.3.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=ja_JP.UTF-8, LC_CTYPE=ja_JP.UTF-8 (charmap=UTF-8), LANGUAGE=ja_JP.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages lxc depends on:
ii  debconf [debconf-2.0]  1.5.71
ii  libc6                  2.29-3
ii  libgcc1                1:8.3.0-6
ii  liblxc1                1:3.1.0+really3.0.4-2
ii  lsb-base               10.2019051400

Versions of packages lxc recommends:
ii  apparmor                     2.13.2-10
ii  bridge-utils                 1.6-2
ii  debootstrap                  1.0.114
ii  dirmngr                      2.2.12-1+deb10u1
ii  dnsmasq-base [dnsmasq-base]  2.80-1
ii  gnupg                        2.2.12-1+deb10u1
ii  iproute2                     4.20.0-2
ii  iptables                     1.8.2-4
pn  libpam-cgfs                  <none>
ii  lxc-templates                3.0.4-1
pn  lxcfs                        <none>
ii  nftables                     0.9.0-2
ii  openssl                      1.1.1c-1
ii  rsync                        3.1.3-8
ii  uidmap                       1:4.5-1.1

Versions of packages lxc suggests:
pn  btrfs-progs  <none>
ii  lvm2         2.03.02-3
pn  python3-lxc  <none>

-- debconf information:
  lxc/auto_update_config: