EchoServer is unbounded after child with running EventMachine is exited.

eventmachine_fork_thread.rb

require 'eventmachine'

module EchoServer
  def post_init
    puts "-- someone connected to the echo server!"
  end

  def receive_data data
    send_data ">>>you sent: #{data}"
    close_connection if data =~ /quit/i
  end

  def unbind
    puts "-- someone disconnected from the echo server!"
  end
end

puts "Forking..."

def start_echo_server
  Thread.new {
    puts "Starting Echo server"

    EventMachine.run {
      EventMachine.start_server "127.0.0.1", 8081, EchoServer
    }
  }
end

def spawn_workers
  if @pid = fork
    @started = start_echo_server unless @started
  else
    puts "Child #{$$}: Sleeping for 5 seconds"
    EventMachine.run {
      EventMachine.start_server "127.0.0.1", 8082, EchoServer
      EventMachine.add_timer(5) do
        puts "Child #{$$}: exiting..."
        exit
      end
    }
  end

  @pid
end

spawn_workers

if @pid
  begin
    # check if we have any child process that died
    wpid, status = Process.waitpid2(-1, Process::WNOHANG)
    wpid or (sleep 0.1 && next)
    spawn_workers

  rescue Errno::ECHILD
    break
  end while true
end