The simplest Vagrant Docker Node.js server example ever

This is the simplest example on the internet of a Docker container running a Node.js web server inside a Vagrant VM on Mac OS X. I searched and searched and couldn't find anything simpler (not that you can't make something slightly simpler).

I stole the Node.js server from the front page of nodejs.com, and pieced the Vagrantfiles and Dockerfile together from various examples I found that didn't quite suit my needs.

My example uses only a base image of Ubuntu 12.04, and then manually installs everything else on top of that. The example uses a Dockerfile rather than an image. The goal is to demonstrate a barebones Node.js web server with all the inner-workings laid out.

Usage

Make sure you have Vagrant and Docker installed. Then, start everything with:

vagrant up --provider="docker"

You can check that your server is running with:

curl http://localhost:8888

Explanation

What's happening in this whole setup? Well, the Vagrantfile specifies Docker as the provider for the environment it's going to setup. That is, the main operating environment is not a VM, but rather a Docker container that pulls an image for its OS. All of this is specified in the Dockerfile referenced from Vagrantfile. Vagrantfile also references Vagrantfile.proxy. This file specifies the configuration of the VM in which the Docker server will run. The Docker server must be run on top of a Linux kernel. By default (without the Vagrantfile.proxy), the Docker server will automatically run in a boot2docker VM. Here, I have opted to use Vagrant's default VM (VirtualBox) for that Docker server. My only reasons-- to keep everything docker, and because boot2docker is tough to work with in regards to IP forwarding.

Vagrantfile.proxy

Vagrant runs the Docker server inside a VM because it needs to run on Linux kernel. We reference this file from Vagrantfile to ensure that Docker is using Vagrant's VM (VirtualBox) as opposed to boot2docker, which kind of sucks when you're dealing with ports. I use ubuntu 12.04 for this.

Vagrantfile

This is the main Vagrantfile, which runs the Docker container. Notice that we tell the provider (Docker) to run its server inside the VM specified by Vagrantfile.proxy.

Dockerfile

This is where the Docker magic happens. There's not much going on here-- Ubuntu updates its repos, installs Node.js, creates a public www directory, moves out Node.js app to it, then runs it.

app.js

This is the super simple Node.js server. It responds to everything with 'Hello World'. No ip is specified, so it defaults to '0.0.0.0'. This is what we want. '127.0.0.1' does not work because of some internal bullshit.