What is Docker?

It’s a way to put your linux applications into their own containers on the same machine or across a network. It’s not the same thing as a VM. It’s far more efficient and your friends will be envious of your dev ops skills.

What is Dokku?

It’s a poor man’s Heroku written in about 100 lines of BASH. You can run it yourself on a $5 digital ocean instance. Unlike Heroku, you have more control over things. After all, it’s your machine. Want to run a background worker? Need an extra cron job? No problem.

Key Features

• “Push to deploy” simplicity that automatically detects the kind of app you are working on.
• Supports tons of “buildpacks” or plugins that auto configure your app based on the framework you are using. Rails support is fantastic.
• It has an awesome ecosystem of ‘host it yourself’ plugins and modules for things like Postgres, MongoDB, Redis, RabbitMQ and all that other stuff the cool kids use.

I’m Sold!

• Setup a domain. Make an A record that points to the digital ocean IP. test.rickcarlino.com points to 162.243.253.93 in my case.
• Image your Digital Ocean box to use Dokku. It requires Ubuntu and DigitalOcean has a Dokku image you can use by default.
• Visit the URL of your DigitalOcean machine. Paste your SSH public key into the text box found on the server. MAC USERS: Use this to load it in clipboard: pbcopy < ~/.ssh/id_rsa.pub.
• Select “Use Virtual Naming for Apps”. If you are frugal and want to run all of your apps off of one box. You will want 1GB of RAM minimum- trust me. Name your default app something like 00default to forgo the need to subdomain your default app.
• git remote add dokku dokku@DOMAIN_NAME_HERE:APP_NAME_HERE** inside your app’s git repo
• git push dokku master

Noteworthy Plugins:

• Supervisord plugin
• PostgreSQL
• MongoDB Plugin

Cheat Sheet

• docker ps: Shows running processes and their status.
• docker kill <container ID>: I’ll give you three guesses
• dokku config:set <app> NAME=value or dokku config:get : Lets you set ENV['SECRETS'] in your app. Useful for open source apps that run in the wild.
• docker logs: Because sometimes production breaks.
• dokku help: A quick overview of all the commands you will ever need (~10).