docker-layercake

Docker is a pretty cool system for making fast-starting Linux containers. The containers start from a snapshot image, run some task or server, then self-destruct when finished, so each image always starts from a fresh state.

Docker requires lxc (Linux containers), which requires Linux, so on a development laptop (Mac OS X), you need to start up a Linux VM using VirutalBox. This requires a layer cake:

• VirtualBox (https://www.virtualbox.org/) to create a full hardware emulator
• vagrant (http://www.vagrantup.com/) to script the creation and provisioning of a Linux VM inside of VirtualBox
• docker (http://www.docker.io/) to run the containers inside your Linux VM

This project is just a set of scripts and config files to create a docker image on my laptop that can run java and node.js programs. The image could be used as a base for building an image with your favorite server or tool.

I am not using this in production, and neither is the company I work for. Consider it a recipe that worked for me.

You must have VirtualBox and vagrant installed. (They're available from the above links.)

The scripts, in order from the outside in:

• setup.sh - Initialize a VM using vagrant.
• Vagrantfile - Configuration for using "raring" ubuntu (required for docker)
• vagrant-provision.sh - Run by vagrant, on the VM, to update the current VirtualBox integration
• setup.sh - Reboots the VM to use the new VirtualBox integration, then asks vagrant to run:
• build-docker-image.sh - Installs docker, fetches the base ubuntu image for docker, installs java and node.js, and saves the new image as "robey/base".

There's also a script to clean up if you want a fresh start, or are tired of playing:

• teardown.sh - Destroy the VM and remove any trace of it from vagrant

You'll know this all works when you do:

$ vagrant ssh -c "sudo docker run robey/base java -version"

and:

$ vagrant ssh -c "sudo docker run robey/base node --version"