Monit_Capistrano_Recipe.rb

namespace :monit do
  desc "Monit unicorn configuration"
  task :unicorn_service_tests, roles: :web do
    run "mkdir -p #{shared_path}/config"

    template "monit_unicorn.rb.erb", "/tmp/monit_unicorn"
    run "#{sudo} mv /tmp/monit_unicorn /etc/monit/conf.d/unicorn_#{application}_#{rails_env}.conf"
    
    unicorn_worker_pids.each do |val|
      worker_template "monit_unicorn_worker.rb.erb", "/tmp/monit_unicorn_#{application}_#{rails_env}_#{val}_worker", val
      run "#{sudo} mv /tmp/monit_unicorn_#{application}_#{rails_env}_#{val}_worker /etc/monit/conf.d/unicorn_#{application}_#{rails_env}_#{val}_worker.conf"
    end
    
    run "#{sudo} monit -g unicorn_#{application}_#{rails_env} reload "
    
  end
  after "monit:unmonitor", "monit:unicorn_service_tests"

  %w[monitor unmonitor].each do |command|
    desc "monit #{command} unicorn_#{application}_#{rails_env}"
    task command, roles: :web do
      #run at group level
      run "#{sudo} monit -g unicorn_#{application}_#{rails_env} #{command} "
    end
  end
  after "deploy", "monit:monitor"
  after "deploy:setup", "monit:monitor"  
  before "deploy", "monit:unmonitor"
  before "deploy:setup", "monit:unmonitor"  

end

Monit_Unicorn_Master.rb.erb

check process unicorn_<%= application %>_<%= rails_env %>
  with pidfile "<%= shared_path %>/pids/unicorn.pid"
  start program = "/etc/init.d/unicorn_<%= application %>_<%= rails_env %> start"
  stop program = "/etc/init.d/unicorn_<%= application %>_<%= rails_env %> stop"
  if mem is greater than 50.0 MB for 1 cycles then restart
  if cpu is greater than 25% for 1 cycles then restart

  group unicorn_<%= application %>_<%= rails_env %>

Monit_Unicorn_Worker.rb.erb

check process unicorn_<%= application %>_<%= rails_env %>_<%= val %>_worker
  with pidfile "<%= shared_path %>/pids/unicorn.worker.<%= val %>.pid"
  start program = "/bin/true"
  stop program = "/etc/init.d/unicorn_<%= application %>_<%= rails_env %> kill_worker <%= val %>"
  if mem is greater than 90.0 MB for 1 cycles then restart
  if cpu is greater than 40% for 3 cycles then restart

  group unicorn_<%= application %>_<%= rails_env %>

Rails_Env_Specific_Variables.rb

set :unicorn_workers, "1"
set :unicorn_worker_pids, (0...(unicorn_workers.to_i)).to_a

worker_template.rb

def worker_template(from, to, val)
  erb = File.read(File.expand_path("../templates/#{from}", __FILE__))
  put ERB.new(erb).result(binding), to
end