I didn’t know that systemd was going to screw with the ethernet interface names in 16.04, so it was quite a surprise when I fired up a new install of Ubuntu 16.04.2 LTS and found enp0s3 instead of my trusty old eth0.

This page has a great write up on why the change was made.

And

This page has a great write up on how to change it back.

I prefer the second link.