resetroot_169route_python2(用于ubuntu12.04和14.04，centos系列)

#!/usr/bin/python

import os
import json
import subprocess
from cloudinit.sources.DataSourceConfigDrive import find_candidate_devs, read_config_drive
from cloudinit.util import mount_cb
from six.moves.urllib.request import urlopen
from six.moves.urllib.parse import urlencode

def shell(cmd):
    sp = subprocess.Popen(cmd, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    out, err = sp.communicate()
    return out, err

INSTANCE_ID_RUN_PATH = "/run/cloud-init/.instance-id"

# Ensure /run/cloud-init/.instance-id not exists so we can reload DataSource from ConfigDrive.
if os.path.isfile(INSTANCE_ID_RUN_PATH):
    os.unlink(INSTANCE_ID_RUN_PATH)

# Before resetroot, We must ensure if 169.254.169.254 have gateway
gateways = []
for dev in find_candidate_devs():
    results = mount_cb(dev, read_config_drive)
    network_data = results.get("networkdata")
    networks = network_data.get("networks",None)
    found = dev
    if found:
        if not networks:
            continue
        for network in networks:
            routes = network.get("routes", None)
            if not routes:
                continue
            for route in routes:
                gateway = route.get('gateway')
                gateways.append(gateway)
        break

if gateways:
    gateway = gateways[0]
    cmd = "route add -host 169.254.169.254 gw %s" % gateway
    out,err = shell(cmd)

data = urlopen("http://169.254.169.254/openstack/latest/meta_data.json").read()
json_data = json.loads(data.decode("utf-8"))

meta = json_data.get("meta")
if meta:
    adminPass =  meta.get("admin_pass")
    if  adminPass:
        os.system("echo 'root:%s' | chpasswd" % adminPass)
        params = urlencode({"delete":True})
        f = urlopen("http://169.254.169.254/openstack/latest/password", params)
        f.read()