metal/17.10:

zyga@fyke:~$ ls -ld /sys/fs/cgroup/freezer/
dr-xr-xr-x 3 root root 0 lis 16 10:20 /sys/fs/cgroup/freezer/

qemu/16.04:

qemu:ubuntu-16.04-64 /root# ls -ld /sys/fs/cgroup/freezer/
dr-xr-xr-x 4 root root 0 Nov 16 10:15 /sys/fs/cgroup/freezer/

qemu/16.04 with lxd/16.04 on top:

ubuntu@my-ubuntu:~$ ls -ld /sys/fs/cgroup/freezer/
drwxrwxr-x 2 nobody root 0 Nov 16 09:13 /sys/fs/cgroup/freezer/

-------------^

nobody != root, no way to perform changes.