lxc_container: permissão negada

Question

Eu tenho a configuração não privilegiada do LXC no meu servidor, ao tentar iniciar um dos meus LXC, recebo este erro:

lxc@web3:/sys/fs/cgroup$ lxc-start -n brainfever
WARN: could not reopen tty: Permission denied
WARN: could not reopen tty: Permission denied
WARN: could not reopen tty: Permission denied
WARN: could not reopen tty: Permission denied
WARN: could not reopen tty: Permission denied
lxc_container: Permission denied - Could not create cgroup '/user.slice/brainfever-1' in '/sys/fs/cgroup/devices'.
lxc_container: Permission denied - cgroup_rmdir: failed to delete /sys/fs/cgroup/freezer/
lxc_container: Permission denied - cgroup_rmdir: failed to delete /sys/fs/cgroup/devices/user.slice
lxc_container: failed creating cgroups
lxc_container: failed to spawn 'brainfever'
lxc_container: The container failed to start.
lxc_container: Additional information can be obtained by setting the --logfile and --logpriority options.



lxc@web3:/sys/fs/cgroup$ ls -l
total 0
dr-xr-xr-x 9 root root  0 Feb 22 15:26 blkio
drwxr-xr-x 3 root root 80 Feb 22 15:26 cgmanager
lrwxrwxrwx 1 root root 11 Feb 22 14:53 cpu -> cpu,cpuacct
dr-xr-xr-x 9 root root  0 Feb 22 15:26 cpu,cpuacct
lrwxrwxrwx 1 root root 11 Feb 22 14:53 cpuacct -> cpu,cpuacct
dr-xr-xr-x 9 root root  0 Feb 22 15:26 cpuset
dr-xr-xr-x 5 root root  0 Feb 22 15:26 devices
dr-xr-xr-x 2 lxc  lxc   0 Feb 22 16:35 freezer
dr-xr-xr-x 9 root root  0 Feb 22 15:26 memory
lrwxrwxrwx 1 root root 16 Feb 22 14:53 net_cls -> net_cls,net_prio
dr-xr-xr-x 9 root root  0 Feb 22 15:26 net_cls,net_prio
lrwxrwxrwx 1 root root 16 Feb 22 14:53 net_prio -> net_cls,net_prio
dr-xr-xr-x 9 root root  0 Feb 22 15:26 perf_event
dr-xr-xr-x 9 root root  0 Feb 22 15:26 pids
dr-xr-xr-x 5 root root  0 Feb 22 15:26 systemd

Lista de LXC's:

lxc@web3:/sys/fs/cgroup$ lxc-ls
artservice_photo_contest  brainfever                happyglass                
meltingspot               mmaccess                  natureandspirit 

O LXC está parado.

lxc@web3:~$ lxc-info -n brainfever
Name:           brainfever
State:          STOPPED

Se mais informações forem necessárias, vou editar a pergunta.