[Lxc-users] cgroup mount point & systemd

[Mickaël Guérin]

Hello,

I have an issue with cgroup mount point selection on my system.
As there is no mount point named "lxc" on my system, LXC uses the first one. But it does not work (see my list of mounts).

furet tmp # grep cgroup /proc/mounts 
tmpfs /sys/fs/cgroup tmpfs rw,nosuid,nodev,noexec,relatime,mode=755 0 0
cgroup /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,release_agent=//lib64/systemd/systemd-cgroups-agent,name=systemd 0 0
cgroup /sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0
cgroup /sys/fs/cgroup/ns cgroup rw,nosuid,nodev,noexec,relatime,ns 0 0
cgroup /sys/fs/cgroup/cpu cgroup rw,nosuid,nodev,noexec,relatime,cpu 0 0
cgroup /sys/fs/cgroup/cpuacct cgroup rw,nosuid,nodev,noexec,relatime,cpuacct 0 0
cgroup /sys/fs/cgroup/memory cgroup rw,nosuid,nodev,noexec,relatime,memory 0 0
cgroup /sys/fs/cgroup/devices cgroup rw,nosuid,nodev,noexec,relatime,devices 0 0
cgroup /sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0
cgroup /sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0


I get the following error from LXC: 
furet tmp # lxc-execute -n toto /usr/bin/ls
lxc-execute: No such file or directory - failed to rename cgroup /sys/fs/cgroup/systemd/2211->/sys/fs/cgroup/systemd/toto
lxc-execute: failed to spawn 'toto'
lxc-execute: No such file or directory - failed to remove cgroup '/sys/fs/cgroup/systemd/toto'

In the manual the solution seems to use an alternative cgroup mount point named lxc ("mount -t cgroup lxc /cgroup4lxc") but that does not work for me, as I can't mount cgroups again :
furet tmp # mount -t cgroup lxc /cgroup/
mount: /tmp/lxc already mounted or /cgroup/ busy

Any idea ?

--  
Mickaël.