deploy.rb for instances under ELB

deploy.rb

require "bundler/capistrano"
require "capistrano_colors"
require "aws-sdk"

set :ssh_options, {:keys => ["YOUR_SSH_KEY"], :auth_methods => ["publickey"]}

default_run_options[:pty] = true

set :application, "YOUR_APPLICATION"
set :repository,  "YOUR_REPOSITORY"
set :branch,      "master"

set :user,        'jenkins'
set :use_sudo,    false

set :scm,         :git
set :scm_verbose, true

set :deploy_to,   "/var/www/#{application}"
set :deploy_via,  :copy

###
# Set roles with ELB instances
###
set :elb_name,    "YOUR_ELB_NAME"

AWS.config({
  :access_key_id     => ENV["AWS_ACCESS_KEY_ID"],
  :secret_access_key => ENV["AWS_SECRET_ACCESS_KEY"],
  :ec2_endpoint      => "ec2.ap-northeast-1.amazonaws.com",
  :elb_endpoint      => "elasticloadbalancing.ap-northeast-1.amazonaws.com"
})

elb          = AWS::ELB.new
lb_instances = elb.load_balancers[elb_name].instances
instance_ips = lb_instances.map { |instance| instance.private_ip_address }

role(:web) { instance_ips }
role(:app) { instance_ips }
role(:db, :primary => true) { instance_ips.first }


namespace :deploy do
  task :start, :roles => :app do
    run "cd #{current_path} && BUNDLE_GEMFILE=#{File.join(current_path, "Gemfile")} bundle exec unicorn_rails -D -E production -c config/unicorn.rb"
  end
  task :stop, :roles => :app do
    run "kill -s QUIT `cat #{shared_path}/pids/unicorn.pid`"
  end
  task :restart, :roles => :app, :except => { :no_release => true } do
    run "kill -s USR2 `cat #{shared_path}/pids/unicorn.pid`"
  end
  task :full_restart, :roles => :app, :except => { :no_release => true } do
    stop
    start
  end
end

## test tasks
task :test_web, :roles => :web do
  run "echo 'Hi!'"
end

task :test_app, :roles => :app do
  run "echo 'Hi!'"
end

task :test_db,  :roles => :db do
  run "echo 'Hi!'"
end