Docker a wrapper around LXC. See Docker (software) on enwiki.
To install Docker on Debian: apt-get install docker.io (note it's NOT just "docker", that's an entirely unrelated package)
For services we recommend using the Deployment Pipeline which is Blubber.
For other docker images, like infrastructure images, we manage them differently.
To just test building a random image a http server without state is a good candidate.
There is a Blubber/Tutorial/HelloWorld that shows how to convert a Blubber file to a Docker file and then build it.