Unicorn + Bluepill + Capistrano with RVM

deploy.rb

$:.unshift(File.expand_path('./lib', ENV['rvm_path']))
require "rvm/capistrano"

set :application, "my_app"
set :repository,  "git@trunksapp.com:myuser/myapp.git"
set :branch,      "production"

set :rvm_ruby_string, "1.9.2"
set :deploy_to,       "/var/applications/"
set :user,            "username"
set :scm,             :git
set :use_sudo,        false

default_run_options[:pty] = true

role :web, "123.45.678.90"
role :app, "123.45.678.90"
role :db,  "123.45.678.90", :primary => true

BP = 'bluepill --no-privileged'

namespace :deploy do

  ##
  # Invoked during initial deployment
  task :start do
    run "cd #{current_path} && bundle --without test --without development"
    run "cd #{current_path} && RACK_ENV=production UNICORN_SERVERS=#{ENV['UNICORN_SERVERS'] || 3} #{BP} load ./app.pill"
  end

  ##
  # Invoked after each deployment afterwards
  task :restart do
    run "cd #{current_path} && bundle --without test --without development"

    ignore_failure { run "cd #{current_path} && #{BP} stop unicorn-cluster && sleep 1 && #{BP} quit && sleep 1" }
    run "cd #{current_path} && RACK_ENV=production UNICORN_SERVERS=#{ENV['UNICORN_SERVERS'] || 3} #{BP} load ./app.pill"
  end
end

##
# Shorthand for ignoring exceptions
def ignore_failure(&block)
  begin
    yield
  rescue
  end
end

unicorn.pill

#! /usr/bin/env ruby

Bluepill.application("my-app") do |app|
  app.process("unicorn") do |process|
    process.pid_file = File.join(RAILS_ROOT, 'tmp', 'pids', 'unicorn.pid')
    process.working_dir = RAILS_ROOT

    process.start_command = "/usr/bin/env UNICORN_SERVERS=#{ENV['UNICORN_SERVERS']} #{UNICORN_PATH} -D -c config/unicorn.rb -E production"
    process.stop_command = "kill -QUIT {{PID}}"
    process.restart_command = "kill -USR2 {{PID}}"

    process.uid = process.gid = 'deploy'

    process.start_grace_time = 8.seconds
    process.stop_grace_time = 5.seconds
    process.restart_grace_time = 13.seconds


    process.monitor_children do |child_process|
      child_process.stop_command = "kill -QUIT {{PID}}"

      child_process.checks :mem_usage, :every => 10.seconds, :below => 150.megabytes, :times => [3,4], :fires => :stop
      child_process.checks :cpu_usage, :every => 10.seconds, :below => 20, :times => [3,4], :fires => :stop
    end
  end
end

unicorn.rb

# Spawn workers - default 3 unless ENV['UNICORN_SERVERS'] is set (passed in via Bluepill)
worker_processes ENV['UNICORN_SERVERS'].nil? ? 3 : ENV['UNICORN_SERVERS'].to_i

# Restart any workers that haven't responded in 30 seconds
timeout 30

# Listen on a Unix data socket
listen File.join(ENV['HOME'], 'tmp', 'sockets', 'rails', 'unicorn.sock'), :backlog => 2048

# Create the pid file
pid File.join(ENV['HOME'], 'tmp', 'pids', 'rails', 'unicorn.pid')

What about with rbenv?

@blackjid Configure your deploy to use rbenv then.