Your Own Private Heroku with DigitalOcean and Dokku

Dokku, Like Heroku But Not

Dokku is one of those projects that I've been hearing about, but haven't had the time to look into. I did that today, finally, and I have to say it's... pretty impressive.

It's 100 lines of shell scripts that manage Docker for you - creating a Heroku-like experience where you can deploy your application using Git. There's a lot to it - but have a read on Jeff Lindsay's blog (he's the creator of Dokku) - he has an interesting screencast that will give you more of an idea.

In summary form: you push your git repo to Dokku and it figures out what to do with it. Let's say it's a Node app - Dokku will create a Docker container for your app (Docker is sort of like a VM, but it uses your processor and memory) and install everything needed for it to run.

For Node, it does this by analyzing your package.json. For Ruby/Rails, your Gemfile. You can also use with Java if you like - but I have no idea how that works.

The whole process takes about 10 seconds, and when you're done... you have a working deployment.

The Walkthrough Is Drop-dead Simple

In my last post about Gitlab I basically summarized DigitalOcean's online walkthrough. I did that because I wanted to underscore just how bleedingly simple this stuff has become.

For setting up Dokku - just have a read of this post and follow what it says.

I used a quick Node app and it almost worked perfectly the first time, but I had to jigger a few things:

• Make sure you have a Procfile in the root of your app that tells Docker how to start your app. This can be as simple as web: npm start or a longer Rails incantation. Don't forget the web: key in there.

• Make sure you specify which node and npm version to use in your package.json file. These go in the "engines" setting.

Here's the package.json I used for a successful deployment:

{
  "name": "application-name",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node ./bin/www"
  },
  "engines": {
    "node": "0.10.26",
    "npm": ">=1.3"
  },
  "dependencies": {
    "express": "~4.0.0",
    "static-favicon": "~1.0.0",
    "morgan": "~1.0.0",
    "cookie-parser": "~1.0.1",
    "body-parser": "~1.0.0",
    "debug": "~0.7.4",
    "jade": "~1.3.0"
  }
}

Do You Need To Do This?

Yes, absolutely. If you're working with Node/Ruby/Python/Whatever Heroku Supports - you'll likely have client demos or just public goof-off code you'll want to share. As a web developer these days, it's really important to have a "playground" where you can publicly play with ideas too.

Heroku is amazing, but it's also pretty expensive when you ramp things up. Deployment can take forever as well! I'm a big fan of owning as much of your content as you can - your blog included (DigitalOcean does Wordpress too).

At the very least - see what Dokku can do, and be amazed at what's possible these days.