danhixon/docker-rails repository overview

⁠docker-rails

A simple Docker Image for running Ruby on Rails Rails applications with Passenger. It is based off danhixon/docker-sshd⁠ so capistrano can connect to it via ssh.

⁠Starting The Container

docker run -d -p 384743:22 -name <containername> -link <dbcontainer>:db -v /var/www/<dir>:/var/www/<dir> -e APP_NAME=<appname> -e DB_USERNAME=$PG_APPUSER -e DB_PASSWORD=$PG_APPUSER_PASSWORD AUTHORIZED_KEYS="$(cat ~/.ssh/id_rsa.pub)" danhixon/rails

When the container starts, the necessary gems will be installed, then the DB will be prepared (created and migrated), and eventually, Passenger will be started in standalone mode. See the start script⁠ which will be triggered by supervisord.

You will also have ssh access by virtue of the danhixon/sshd⁠ base image.

###Remarks

1. Link to a DBMS (<dbcontainer>) of your choice. It works with danhixon/ubuntu-postgres.
2. <dir> must be equal to $APP_NAME and - when using Capistrano - be the same on the host and in the container for deployments (because of absolute symlinks)
3. Use AUTHORIZED_KEYS to grant sshd access to your deployment user.
4. Override these default environment variables as needed (using -e KEY=value):

• RAILS_ENV=production

⁠Database Connection

When linked to another container holdig your database, use something like this in config/database.yml:

production:
  adapter: postgresql
  database: betastore_production
  username: <%= ENV['DB_USERNAME'] %>
  password: <%= ENV['DB_PASSWORD'] %>
  host: <%= ENV['DB_PORT_5432_TCP_ADDR'] %>
  port: <%= ENV['DB_PORT_5432_TCP_PORT'] %>
  pool: 5
  timeout: 5000

⁠Serving The App

To access your Rails app from "the outside", install a reverse proxy on the host system and point it to the container's IP on port 80.

I use Apache2. Here's how to set it up:

1. Install Apache: sudo apt-get install apache2
2. Create a new site under /etc/apache2/sites-available, e.g. a file called appname:

<VirtualHost *:80>
    ServerName appname.your.domain

    ErrorLog ${APACHE_LOG_DIR}/appname-error.log
    CustomLog ${APACHE_LOG_DIR}/appname-access.log combined

    ProxyRequests Off
    ProxyPass / http://containerip:80/
    ProxyPreserveHost On

    <Proxy *>
        Order deny,allow
        Allow from all
    </Proxy>
</VirtualHost>

N.B.: You can get the container's IP address by using: docker inspect -format '{{ .NetworkSettings.IPAddress }}' <containername>

1. Enable the modules proxy and proxy_http:

sudo a2enmod proxy
sudo a2enmod proxy_http

1. Enable your site and restart Apache:

sudo a2ensite yoursite
sudo service apache2 restart

1. Test connection by pointing your browser to http://appname.your.domain⁠