class DRb::ExtServManager

def invoke_service_command(name, command)
  raise "invalid command. name: #{name}" unless command
  synchronize do
    return if @servers.include?(name)
    @servers[name] = false
  end
  uri = @uri || DRb.uri
  if command.respond_to? :to_ary
    command = command.to_ary + [uri, name]
    pid = spawn(*command)
  else
    pid = spawn("#{command} #{uri} #{name}")
  end
  th = Process.detach(pid)
  th[:drb_service] = name
  th
end