Ubuntu 14.04 x64 + Rails 4 + Nginx + Unicorn + PostgreSQL + Capistrano 3 Setup Instructions

Rails 4 Deployment Configuration

### Ubuntu 14.04 x64 + Rails 4 + Nginx + Unicorn + PostgreSQL + Capistrano 3

SSH into Root

    $ ssh root@123.123.123.123

Change Root Password

    $ passwd

Add Deploy User

    $ adduser deployer

Update Sudo Privileges

    $ visudo
    username ALL=(ALL:ALL) ALL

Configure SSH

    $ vi /etc/ssh/sshd_config
    Port 22 # Change (1025..65536)
    Protocol 2 # Change
    PermitRootLogin no  # Change
    UseDNS no # Add
    AllowUsers deployer # Add

Reload SSH

    $ reload ssh
        
SSH with Deploy User (Don't close root)

    $ ssh -p 1026 deployer@123.123.123.123

Install Curl

    $ sudo apt-get update
    $ sudo apt-get install curl

Install RVM

    $ curl -L get.rvm.io | bash -s stable
    $ source ~/.rvm/scripts/rvm
    $ rvm requirements
    $ rvm install 2.2.0
    $ rvm use 2.2.0 --default
    $ rvm rubygems current

Install PostgreSQL

    $ sudo apt-get install postgresql postgresql-server-dev-9.3
    $ gem install pg -- --with-pg-config=/usr/bin/pg_config

Create Postgres User

    $ sudo -u postgres psql
    create user deployer with password 'password';
    alter role deployer superuser createrole createdb replication;
    create database MYAPP_production owner deployer;

Install GIT

    $ sudo apt-get install git-core

Install Bundler

    $ gem install bundler

Setup Nginx

    $ sudo apt-get install nginx
    $ nginx -h
    $ cat /etc/init.d/nginx
    $ /etc/init.d/nginx -h
    $ sudo service nginx start
    $ sudo vim /etc/nginx/sites-enabled/default

    upstream unicorn {
      server unix:/tmp/unicorn.MYAPP.sock fail_timeout=0;
    }

    server {
      listen 80 default deferred;
      # server_name example.com;
      root /home/deployer/apps/MYAPP/current/public;

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

      location ~ ^/(robots.txt|sitemap.xml.gz)/ {
        root /home/deployer/apps/MYAPP/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;
    }
    
Add Unicorn

	$ vim Gemfile
	gem 'unicorn'    

Update Unicorn Config

	$ vim config/unicorn/production.rb

    root = "/home/deployer/apps/MYAPP/current"
    working_directory root

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

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

    worker_processes Integer(ENV['WEB_CONCURRENCY'])
    timeout 30
    preload_app true

    listen '/tmp/unicorn.spui.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
      end

      defined?(ActiveRecord::Base) and
        ActiveRecord::Base.connection.disconnect!
    end

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

      defined?(ActiveRecord::Base) and
        ActiveRecord::Base.establish_connection
    end

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

Add Capistrano

    $ vim Gemfile
    
    group :development do
      gem 'capistrano-rails'
      gem 'capistrano-rvm'
      gem 'capistrano3-unicorn'
    end

Install Capistrano

    $ bundle exec cap install

Update Capistrano 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 Capistrano Deploy Config

	$ vim config/deploy.rb

    lock '3.3.5'

    set :application, 'spui'
    set :repo_url, 'git@github.com:MYGITHUB/MYAPP.git'

    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:reload'
      end
    end
    
Update Production Deploy Config

	$ vim config/deploy/production.rb

    set :port, 22
    set :user, 'deployer'
    set :deploy_via, :remote_cache
    set :use_sudo, false

    server '123.333.333.333',
      roles: [:web, :app, :db],
      port: fetch(:port),
      user: fetch(:user),
      primary: true

    set :deploy_to, "/home/#{fetch(:user)}/apps/#{fetch(:application)}"

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

    set :rails_env, :production
    set :conditionally_migrate, true    

Create Unicorn Init Script

  Let's create an init script so we can easily start and stop Unicorn, and ensure that it will start on boot.
  
  Create a script and open it for editing with this command (replace the unicorn_app part with your application name, if you wish):

  sudo vi /etc/init.d/unicorn_appname
  
Copy and paste the following code block into it, and be sure to substitute USER and APP_NAME with the appropriate values  

  #!/bin/sh
  
  ### BEGIN INIT INFO
  # Provides:          unicorn
  # Required-Start:    $all
  # Required-Stop:     $all
  # Default-Start:     2 3 4 5
  # Default-Stop:      0 1 6
  # Short-Description: starts the unicorn app server
  # Description:       starts unicorn using start-stop-daemon
  ### END INIT INFO
  
  set -e
  
  USAGE="Usage: $0 <start|stop|restart|upgrade|rotate|force-stop>"
  
  # app settings
  USER="deploy"
  APP_NAME="appname"
  APP_ROOT="/home/$USER/$APP_NAME"
  ENV="production"
  
  # environment settings
  PATH="/home/$USER/.rbenv/shims:/home/$USER/.rbenv/bin:$PATH"
  CMD="cd $APP_ROOT && bundle exec unicorn -c config/unicorn.rb -E $ENV -D"
  PID="$APP_ROOT/shared/pids/unicorn.pid"
  OLD_PID="$PID.oldbin"
  
  # make sure the app exists
  cd $APP_ROOT || exit 1
  
  sig () {
    test -s "$PID" && kill -$1 `cat $PID`
  }
  
  oldsig () {
    test -s $OLD_PID && kill -$1 `cat $OLD_PID`
  }
  
  case $1 in
    start)
      sig 0 && echo >&2 "Already running" && exit 0
      echo "Starting $APP_NAME"
      su - $USER -c "$CMD"
      ;;
    stop)
      echo "Stopping $APP_NAME"
      sig QUIT && exit 0
      echo >&2 "Not running"
      ;;
    force-stop)
      echo "Force stopping $APP_NAME"
      sig TERM && exit 0
      echo >&2 "Not running"
      ;;
    restart|reload|upgrade)
      sig USR2 && echo "reloaded $APP_NAME" && exit 0
      echo >&2 "Couldn't reload, starting '$CMD' instead"
      $CMD
      ;;
    rotate)
      sig USR1 && echo rotated logs OK && exit 0
      echo >&2 "Couldn't rotate logs" && exit 1
      ;;
    *)
      echo >&2 $USAGE
      exit 1
      ;;
  esac  

Save and exit. This will allow you to use service unicorn_appname to start and stop your Unicorn and your Rails application.

Update the script's permissions and enable Unicorn to start on boot:
  
  sudo chmod 755 /etc/init.d/unicorn_appname
  sudo update-rc.d unicorn_appname defaults

Let's start it now:
  sudo service unicorn_appname start

Now your Rails application's production environment is running under Unicorn, and it's listening on the shared/sockets/unicorn.sock socket.


Add SSH Key to DigitalOcean

    $ cat ~/.ssh/id_rsa.pub | ssh -p 22 username@123.123.123.123 'cat >> ~/.ssh/authorized_keys'
    
Say Hi to Github

    # follow the steps in this guide if receive permission denied(public key)
    # https://help.github.com/articles/error-permission-denied-publickey
    $ ssh github@github.com    

Check Deployment (Commit and Push)

    $ cap production deploy:check
    
Deploy

    $ cap production deploy
    
Thanks to [James Dullaghan](https://gist.github.com/JamesDullaghan/5941259) for his help.