Deploying Rails to AWS

TL;DR If Rails can be deployed on a VPS, can it be deployed on a shared server?

I want to build applications which value. One of the most important steps in my value chain is deploying this application; bringing the application into the customer’s hands. There are many platforms through which I can deliver my application. One of the easiest to use is Heroku which provides a platform, and orchestrates most of the deployment details away. For the longest time, I deployed Rails applications using the command below

git push heroku feature-branch:master

Recently, I looked into what it would take to deploy Rails into a VPS which I had complete control over. It was quite an interesting exercise; laced with even more interesting problems. Here, I would detail the steps I used in getting Rails 6 deployed on an AWS VPS.

What did I need

• A server
• A database
• A deployment tool
• An application to deploy

A Server

To get the server running, I provisioned an Ubuntu server on AWS EC2. This is available in the free tier. I chose Ubuntu because I am comfortable with its terminal environment. You can use any linux box you’re comfortable with. The commands I use here are specific to Ubuntu. Do well to find and use the equivalent for your Linux box.

To Launch the EC2 instance:

• select EC2 from the list of AWS services
• click on “Launch Instance”
• the defaults should be fine, but do well to click through them
• at the Security Group, make sure to open up port 80 for web traffic; it’s closed by default

At this point, I am thinking “Someone should have done the work. This isn’t novel.” So I go to google, searching. I see this fanta-amazing post from GoRails. Chris Oliver does a good job in setting up Rails on an EC2 instance. This remains my north star for deployments.

The only pitfall I faced here was around assets. See… I had created a new rails application to deploy to the server. There were no controllers, no models, nothing. Just a vanilla Rails application. Turns out Capistrano did not feel the need to cmopile assets since it was not needed at the time.

Always have an application you want to deploy before deploying

With Rails now deployed on AWS, running on NGINX + Passenger, deployed with Capistrano… I began to think if this is possible on shared servers.

Updates

Deploy Keys

Github has this neat feature where it allows you to add SSH keys per repository. Github calls this “Deploy Keys”. The idea is to give a certain key rights to a reposoty so it can pull (by default) contents of that repository. This makes it easy for servers to add their public SSH keys to these repositories as Deploy keys and allow deployment do on smoothly.

SSH Forwarding

On AWS, the acceptable way to ues an SSH client to access your server us through a PEM file. When deplying using Capistrano, you would have to tell Capistrano to use this private key while running your deploys.

# in config/deploy.rb

set :ssh_options, {
  forward_agent: true,
  auth_methods: %w[publickey],
  keys: %w[/path/to/key.pem]
}