def METHOD_NAME():
    """The main function. Hier spielt die Musik.
    """
    # logic taken from mysqltuner.pl:get_kernel_info(), v1.9.8
    # parse the command line, exit with UNKNOWN if it fails
    try:
        args = parse_args()
    except SystemExit:
        sys.exit(STATE_UNKNOWN)
    # init some vars
    msg = ''
    state = STATE_OK
    perfdata = ''
    # count ports
    opened_ports = get_opened_ports()
    if args.MAXPORTSALLOWED > 0:
        if opened_ports == 0:
            msg += 'No ports checked (psutil missing). '
        if opened_ports > args.MAXPORTSALLOWED:
            state = STATE_WARN
            msg += ('There are too many listening ports: {} opened > {} allowed '
                    '(consider dedicating a server for your database installation with '
                    'less services running on). ').format(opened_ports, args.MAXPORTSALLOWED)
    perfdata += lib.base.get_perfdata('mysql_opened_ports', opened_ports, None, None, None, 0, None)
    # get kernel settings on linux
    if lib.base.LINUX:
        result = get_sysctl('vm.swappiness')
        if not result:
            lib.base.cu('Permission denied reading `vm.swappiness`')
        if int(result) > 10:
            state = STATE_WARN
            msg += 'vm.swappiness is {}, should be <= 10 (use `echo 10 > /proc/sys/vm/swappiness`). '.format(
                result,
            )
        perfdata += lib.base.get_perfdata('mysql_kernel_vm.swappiness', result, '%', None, None, 0, 100)
        # only if /proc/sys/sunrpc exists
        if os.path.isdir('/proc/sys/sunrpc'):
            result = get_sysctl('sunrpc.tcp_slot_table_entries')
            if int(result) <= 100:
                state = STATE_WARN
                msg += 'sunrpc.tcp_slot_table_entries is {}, should be > 100 (use `echo 128 > /proc/sys/sunrpc/tcp_slot_table_entries`). '.format(
                    result,
                )
            perfdata += lib.base.get_perfdata('mysql_kernel_sunrpc.tcp_slot_table_entries', result, None, None, None, 0, None)
        if os.path.isfile('/proc/sys/fs/aio-max-nr'):
            result = get_sysctl('fs.aio-max-nr')
            if int(result) < 1000000:
                state = STATE_WARN
                msg += 'fs.aio-max-nr is {}, should be > 1M (use `echo 1048576 > /proc/sys/fs/aio-max-nr`). '.format(
                    result,
                )
            perfdata += lib.base.get_perfdata('mysql_kernel_fs.aio-max-nr', result, None, None, None, 0, None)
    if not msg:
        msg = 'Everything is ok.'
    # over and out
    lib.base.oao(msg, state, perfdata, always_ok=args.ALWAYS_OK)