def perform_prestart_checks(expected_hostname):
  # Check if current hostname is equal to expected one (got from the server
  # during bootstrap.
  global config

  if expected_hostname is not None:
    current_hostname = hostname.hostname(config)
    if current_hostname != expected_hostname:
      print("Determined hostname does not match expected. Please check agent "
            "log for details")
      msg = "Ambari agent machine hostname ({0}) does not match expected ambari " \
            "server hostname ({1}). Aborting registration. Please check hostname, " \
            "hostname -f and /etc/hosts file to confirm your " \
            "hostname is setup correctly".format(current_hostname, expected_hostname)
      logger.error(msg)
      sys.exit(1)