[lxc-users] Unable to launch unpriviledged containers on Desktop

[Serge Hallyn]

Quoting Winael (vinzjobard at ubuntu.com):
...
> lxc-start 20160311171257.911 ERROR    lxc_cgfs -
> cgfs.c:lxc_cgroupfs_create:1007 - Permission denied - Could not create
> cgroup '/user/1000.user/c2.session/lxc' in '/sys/fs/cgroup/systemd'.

You must own your systemd cgroup.  Apparently you don't.  This could
be becaues you don't have things set up right, but there are also a
lot of bugs going around right now that can mess that up for you.
Ideally you would have the very latest libpam-cgfs installed, and that
will do it all for you.  Otherwise look at /proc/self/cgroup, and see
what your systemd cgroup is.  Assuming it is something like

1:name=systemd:/user.slice/user-1000.slice/session-c2.scope

you can just chown it to yourself by doing

sudo chown $(id -u):$(id -g) /sys/fs/cgroup/systemd/`awk -F: '/systemd/ { print $3 }' /proc/self/cgroup`

-serge