I struggle to get docker, I have always used just shell scripts (test locally using vagrant, push to openstack) until I came across Nix http://nixos.org/nix/
@boycott: i like docker - it means i can separate the configuration of the compute services of a cluster from the configuration of the app components, and then deploy app components to cluster nodes using something like mesos (which i use) or kubernetes (which i haven't used)
I shall have to give it a try sometime
Docker is pretty cool. And if you were used to doing shellscripts creating a container with Dockerfile is basically this. And you can test your production environment more or less 1:1 locally before you commit to pushing the code.
If you like nix there was this - https://github.com/zefhemel/nix-docker - but it seems to be discontinued. But the idea seems legit so maybe it's worth looking into if someone created something similar.
vagrant, nix and docker, will have to investigate, thank you - I like to have as few moving parts as possible so it might be a step too far!