puma config for rvm, capistrano 3 and upstart. Tested on Ubuntu 12.04 LTS and 14.04 LTS

config_puma.rb

#!/usr/bin/env puma

app_path = '/var/www/YOUR_APP_NAME/current'
directory app_path
environment 'production'
daemonize true
pidfile "#{app_path}/tmp/pids/puma.pid"
state_path "#{app_path}/tmp/pids/puma.state"
stdout_redirect "#{app_path}/log/puma_error.log", "#{app_path}/log/puma_access.log", true
threads 0,16
bind "unix:#{app_path}/tmp/sockets/puma.sock"

workers 0

preload_app!


on_restart do
  puts 'Refreshing Gemfile'
  ENV["BUNDLE_GEMFILE"] = "#{app_path}/Gemfile"
end

deploy.rb

SSHKit.config.command_map[:run]      = "cd #{fetch(:deploy_to)}/current && /usr/local/rvm/bin/rvm default do"

set :puma_conf, "#{shared_path}/config/puma.rb"
set :puma_state, "#{shared_path}/tmp/pids/puma.state"
set :puma_pid, "#{shared_path}/tmp/pids/puma.pid"
set :puma_socket, "#{shared_path}/tmp/sockets/puma.sock"

set :linked_files, %w{config/puma.rb}
set :linked_dirs, %w{tmp/pids tmp/sockets}

etc_init_puma-manager.conf

# /etc/init/puma-manager.conf - manage a set of Pumas

# This example config should work with Ubuntu 12.04+.  It
# allows you to manage multiple Puma instances with
# Upstart, Ubuntu's native service management tool.
#
# See puma.conf for how to manage a single Puma instance.
#
# Use "stop puma-manager" to stop all Puma instances.
# Use "start puma-manager" to start all instances.
# Use "restart puma-manager" to restart all instances.
# Crazy, right?
#

description "Manages the set of puma processes"

# This starts upon bootup and stops on shutdown
start on runlevel [2345]
stop on runlevel [06]

# Set this to the number of Puma processes you want
# to run on this machine
env PUMA_CONF="/etc/puma.conf"

pre-start script
  for i in `cat $PUMA_CONF`; do
    app=`echo $i | cut -d , -f 1`
    logger -t "puma-manager" "Starting $app"
    start puma app=$app
  done
end script

etc_init_puma.conf

# /etc/init/puma.conf - Puma config

# This example config should work with Ubuntu 12.04+.  It
# allows you to manage multiple Puma instances with
# Upstart, Ubuntu's native service management tool.
#
# See workers.conf for how to manage all Puma instances at once.
#
# Save this config as /etc/init/puma.conf then manage puma with:
#   sudo start puma app=PATH_TO_APP
#   sudo stop puma app=PATH_TO_APP
#   sudo status puma app=PATH_TO_APP
#
# or use the service command:
#   sudo service puma {start,stop,restart,status}
#

description "Puma Background Worker"

# no "start on", we don't want to automatically start
stop on (stopping puma-manager or runlevel [06])

# change apps to match your deployment user if you want to use this as a less privileged user (recommended!)
setuid deploy
setgid deploy

respawn
respawn limit 3 30

instance ${app}

script
# this script runs in /bin/sh by default
# respawn as bash so we can source in rbenv/rvm
# quoted heredoc to tell /bin/sh not to interpret
# variables
exec /bin/bash <<'EOT'
  # set HOME to the setuid user's home, there doesn't seem to be a better, portable way
  export HOME="$(eval echo ~$(id -un))"

  if [ -d "$HOME/.rbenv/bin" ]; then
    export PATH="$HOME/.rbenv/bin:$HOME/.rbenv/shims:$PATH"
  elif [ -f  /etc/profile.d/rvm.sh ]; then
    source /etc/profile.d/rvm.sh
  elif [ -f /usr/local/rvm/scripts/rvm ]; then
    source /etc/profile.d/rvm.sh
  elif [ -f "$HOME/.rvm/scripts/rvm" ]; then
    source "$HOME/.rvm/scripts/rvm"
  elif [ -f /usr/local/share/chruby/chruby.sh ]; then
    source /usr/local/share/chruby/chruby.sh
    if [ -f /usr/local/share/chruby/auto.sh ]; then
      source /usr/local/share/chruby/auto.sh
    fi
    # if you aren't using auto, set your version here
    # chruby 2.0.0
  fi

  # cd helps setting ruby version and local environment variables
  cd $app

  logger -t puma "Starting server: $app"
  exec bundle exec $app/bin/puma --config $app/config/puma.rb
EOT
end script

etc_puma.conf

/var/www/YOUR_APP_NAME/current

puma.cap

namespace :puma do
  desc 'Start the puma server'
  task :start do
    on roles(:web) do
      execute :run, "#{fetch(:deploy_to)}/current/bin/puma --config #{fetch(:puma_conf)}"
    end
  end

  desc 'Restart the puma server'
  task :restart do
    on roles(:web) do
      if capture("[ -S #{fetch(:puma_socket)} ] && echo '1' || echo '0'") == '1' &&
         capture("[ -f #{fetch(:puma_pid)} ] && echo '1' || echo '0'") == '1'
        debug "Hot-restarting puma..."
        execute "kill -s SIGUSR2 `cat #{fetch(:puma_pid)}`"
        debug "Doublechecking the process restart..."
        sleep 5
        if capture("[ -S #{fetch(:puma_socket)} ] && echo '1' || echo '0'") == '1'
          debug "Restart success!"
        else
          debug "Failed! Trying to cold reboot"
          execute :run, "#{fetch(:deploy_to)}/current/bin/puma --config #{fetch(:puma_conf)}"
        end
      else
        debug "Server not running. Starting..."
        execute :run, "#{fetch(:deploy_to)}/current/bin/puma --config #{fetch(:puma_conf)}"
      end
    end
  end

  desc 'Stop the puma server'
  task :stop do
    on roles(:web) do
      pid = if capture("[ -f #{fetch(:puma_pid)} ] && echo '1' || echo '0'") == '1'
        capture "cat #{fetch(:puma_pid)}"
      elsif capture("[ -f #{fetch(:puma_state)} ] && echo '1' || echo '0'") == '1'
        capture "cat #{fetch(:puma_state)} | sed -n 2p | awk -F ' ' '{print $2}'"
      end
      execute "rm -f #{fetch(:puma_pid)}"
      execute "rm -f #{fetch(:puma_socket)}"
      execute "rm -f #{fetch(:puma_state)}"
      execute "kill -s SIGTERM #{pid}"
    end
  end
end

before 'puma:start', 'rvm:hook'
before 'deploy:restart', 'puma:restart'