Running a Rails application with Docker

This how-to will guide you on how to run a Rails application using Docker.

Assumptions

• You have docker installed
• You already have the rails application with a docker-compose.yml file

Steps

The first step is to recognize the names from the docker-compose.yml file. It should look like:

version: '2'

volumes:
  postgres-data:
    driver: local
  gems:
    driver: local

services:
  db:
  test: &app
  mailcatcher:
  web:
    <<: *app

We often call the main service to lift the rails server as web. Let's install the gems:

% docker-compose run --rm web bundle install

This can take a while

Once the command finishes its execution, it is now time to create and migrate the database:

% docker-compose run --rm rake db:create db:migrate db:seed

Finally you are ready to start the web server by just running:

% docker-compose up -d

This last command will run every service on the docker-compose.yml file meaning run the rails application. You will be able to see the running app at http://localhost:3000. It may take a while befire you can see anything.