Deploying a Rails Application with Capistrano 3, RVM, Nginx and Unicorn

February 01, 2015

If you are planning to deploy your Rails application using Capistrano 3, RVM, Unicorn, and Nginx then this is for you. You can follow these steps to help you automate your deployment to your cloud server. If you want to secure your server, you can read through this.

Install RVM

Log in to your system and install RVM. RVM has a good installation guide which you can find in detail here.

Or, you can just run this on your server.

$ curl -sSL https://get.rvm.io | bash -s stable --ruby

To verify

$ rvm version

rvm 1.25.14 (stable) by Wayne E. Seguin <wayneeseguin@gmail.com>, Michal Papis <mpapis@gmail.com> [https://rvm.io/]

Install Git

For Ubuntu:

$ sudo apt-get install git

If you are running on CentOS

$ sudo yum install git

To check whether it installed correctly

$ git --version

git version

Setup Nginx

Nginx is a reverse proxy server. It basically serves all the client requests coming in to your server, and directs it to the appropriate backend server. In this case, your backend server would be Unicorn which hosts your Rails application.

Installing Nginx is simple with the package management tool.

For Ubuntu

sudo apt-get install nginx

For CentOS

sudo yum install nginx

Once you have this installed, you will need to add default.conf.

$ sudo vim /etc/nginx/conf.d/default.conf

Add the following content. Make sure to edit it to match your configurations

upstream unicorn {
  server unix:/tmp/unicorn.[APP_NAME].sock fail_timeout=0;

server {
  listen 80 default deferred;
  # server_name example.com;
  root [APP_DIRECTORY]/[APP_NAME]/current/public; # e.g. /var/apps/rails_blog/current/public

  location ^~ /assets/ {
    gzip_static on;
    expires max;
    add_header Cache-Control public;

  location ~ ^/(robots.txt|sitemap.xml.gz)/ {
    root [APP_DIRECTORY]/[APP_NAME]/current/public; # e.g. /var/apps/rails_blog/current/public

  try_files $uri/index.html $uri @unicorn;
  location @unicorn {
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect off;
    proxy_pass http://unicorn;

  error_page 500 502 503 504 /500.html;
  client_max_body_size 4G;
  keepalive_timeout 10;

After adding this config, try to start nginx

sudo service nginx start

You can check whether nginx is running correctly

$ ps aux|grep nginx

You should see nginx listed in the result.

Setup your App

Configure Unicorn in your Rails application

Add the unicorn gem into your Gemfile

$ vim Gemfile

gem 'unicorn'

Then add the unicorn configuration:

$ vim config/unicorn/production.rb

root = "[APP_DIRECTORY]/[APP_NAME]/current" # e.g. /var/apps/rails_blog/current
working_directory root

pid "#{root}/tmp/pids/unicorn.pid"

stderr_path "#{root}/log/unicorn.log"
stdout_path "#{root}/log/unicorn.log"

worker_processes 8 # update this with your preference
timeout 30
preload_app true

listen '/tmp/unicorn.[APP_NAME].sock', backlog: 64

before_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn master intercepting TERM and sending myself QUIT instead'
    Process.kill 'QUIT', Process.pid

  defined?(ActiveRecord::Base) and

after_fork do |server, worker|
  Signal.trap 'TERM' do
    puts 'Unicorn worker intercepting TERM and doing nothing. Wait for master to send QUIT'

  defined?(ActiveRecord::Base) and

# Force the bundler gemfile environment variable to
# reference the capistrano "current" symlink
before_exec do |_|
  ENV['BUNDLE_GEMFILE'] = File.join(root, 'Gemfile')

Add Capistrano 3 to your app

Add the gem

$ vim Gemfile

group :development do
  gem 'capistrano-rails'
  gem 'capistrano-rvm'
  gem 'capistrano3-unicorn'

Generate the necessary Capistrano files

$ bundle exec cap install

Update the generated Capfile

$ vim Capfile

require 'capistrano/setup'
require 'capistrano/deploy'
require 'capistrano/rvm'
require 'capistrano/bundler'
require 'capistrano/rails/assets'
require 'capistrano/rails/migrations'
require 'capistrano3/unicorn'

# Load custom tasks from `lib/capistrano/tasks' if you have any defined
Dir.glob('lib/capistrano/tasks/*.rake').each { |r| import r }    

Update deploy.rb

$ vim config/deploy.rb

lock '3.3.5'

set :application, [APP_NAME]
set :repo_url, 'git@github.com:[GITHUB_ACCOUNT_NAME]/[APP_NAME].git' # change this to your git server

ask :branch, proc { `git rev-parse --abbrev-ref HEAD`.chomp }.call

set :use_sudo, false
set :bundle_binstubs, nil
set :linked_files, fetch(:linked_files, []).push('config/database.yml')
set :linked_dirs, fetch(:linked_dirs, []).push('log', 'tmp/pids', 'tmp/cache', 'tmp/sockets', 'vendor/bundle', 'public/system')

after 'deploy:publishing', 'deploy:restart'

namespace :deploy do
  task :restart do
    invoke 'unicorn:stop'
    invoke 'unicorn:reload'

  task :stop do
    invoke 'unicorn:stop'

Update capistrano production.rb

$ vim config/deploy/production.rb

set :port, 22
set :user, [username] # e.g. 'deploy'
set :deploy_via, :remote_cache
set :use_sudo, false
set :branch, [BRANCH_TO_DEPLOY] # e.g. 'master'

server [HOST_IP], # e.g. 192.xxx.xxx.xxx
  roles: [:web, :app, :db],
  port: fetch(:port),
  user: fetch(:user),
  primary: true

set :deploy_to, "[APP_DIRECTORY]/#{fetch(:application)}" # e.g. "/var/apps/rails_blog"

set :ssh_options, {
  forward_agent: true,
  auth_methods: %w(publickey),
  user: 'deployer',

set :rails_env, :production
set :conditionally_migrate, true

Setup Git Server

To make sure that the deployment script runs smoothly, you need to add your server’s pub key to your git server.

Generate your pub key if you have not done so:

ssh-keygen -t rsa -C "[EMAIL_ADDRESS]"

This will generate a public key: ~/.ssh/id_rsa.pub

Copy the content of this file onto your git server profile.

Verify deploy

Once everything has been setup, try to verify everything by running this

cap production deploy:check

If everything runs smoothly, then you are more or less set.

Deploy application

To deploy this in production

cap production deploy

That should deploy your app in production. Once you access the IP address of your server on a browser, you should be greeted by your app’s home page.

Many thanks to Chuck J Hardy for his guide which helped me tremendously.

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