$ time lxc launch ubuntu:yakkety
Generating a client certificate. This may take a minute...
If this is your first time using LXD, you should also run: sudo lxd init
To start your first container, try: lxc launch ubuntu:16.04

Creating lucky-jay
Starting lucky-jay                 

real	0m27.524s
user	0m3.360s
sys	0m0.012s
thomasthorne@thorne-ul-dt:~$ sudo lxd init
LXD init cannot be used at this time.
+However if all you want to do is reconfigure the network,
+you can still do so by running "sudo dpkg-reconfigure -p medium lxd"

error: You have existing containers or images. lxd init requires an empty LXD.
thomasthorne@thorne-ul-dt:~$ lxc exec lucky-jay -- /bin/bash 
root@lucky-jay:~# sudo -u ubuntu -i
To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.

ubuntu@lucky-jay:~$