code: def set_ntp_server(server):
      
      log = logging.getLogger(mod_logger + '.set_ntp_server')
  
      # Ensure the hostname is a str
      if not isinstance(server, basestring):
          msg = 'server argument must be a string'
          log.error(msg)
          raise CommandError(msg)
      # Ensure the ntp.conf file exists
      ntp_conf = '/etc/ntp.conf'
      if not os.path.isfile(ntp_conf):
          msg = 'File not found: {f}'.format(f=ntp_conf)
          log.error(msg)
          raise CommandError(msg)
      log.info('Clearing out existing server entries from %s...', ntp_conf)
      try:
          sed(ntp_conf, '^server.*', '', g=0)
      except CommandError:
          _, ex, trace = sys.exc_info()
          msg = 'Unable to update file: {f}\n{e}'.format(f=ntp_conf, e=str(ex))
          log.error(msg)
          raise CommandError, msg, trace
      out_str = 'server ' + server
      log.info('Appending server: %s', out_str)
      with open(ntp_conf, 'a') as f:
          f.write(out_str)
      log.info('Successfully updated file: {f}'.format(f=ntp_conf))
docs: Sets the NTP server on Linux
  
      :param server: (str) NTP server IP or hostname
      :return: None
      :raises CommandError