How to create a LXC Ubuntu container in 15 seconds

Run this:

lxc launch ubuntu:18.04 mycontainer

In case you see this error message

Error: Failed container creation: No storage pool found. Please create a new storage pool

see How to fix lxd ‘Failed container creation: No storage pool found. Please create a new storage pool.’

Now you can connect to your container using

lxc exec mycontainer /bin/bash