packstack gen-answer-file get localhost ip

packstack-utils-network.py

# -*- coding: utf-8 -*-

import re
import socket

                                                                                                                                                                                         
def get_localhost_ip():
    """
    Returns IP address of localhost.
    """
    # TO-DO: Will probably need to find better way to find out localhost
    #        address.

    # find nameservers
    ns_regex = re.compile('nameserver\s*(?P<ns_ip>[\d\.\:]+)')
    # 想让哪块网卡被default，修改/etc/resolv.conf即可。
    rc, resolv = execute('cat /etc/resolv.conf | grep nameserver',
                         can_fail=False, use_shell=True, log=False)
    nsrvs = []
    for line in resolv.split('\n'):
        match = ns_regex.match(line.strip())
        if match:
            nsrvs.append(match.group('ns_ip'))

    # try to connect to nameservers and return own IP address
    nsrvs.append('8.8.8.8')  # default to google dns
    for i in nsrvs:
        try:
            s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            s.connect((i, 0)) 
            loc_ip = s.getsockname()[0]
        except socket.error:
            continue
        else:
            return loc_ip
    raise NetworkError('Local IP address discovery failed. Please set '
                       'nameserver correctly.')