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# Copyright (C) 2013 Craig Tracey
# Copyright (C) 2013 Hewlett-Packard Development Company, L.P.
#
# Author: Craig Tracey <craigtracey@gmail.com>
# Author: Juerg Haefliger <juerg.haefliger@hp.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
"""
Resolv Conf
-----------
**Summary:** configure resolv.conf
This module is intended to manage resolv.conf in environments where early
configuration of resolv.conf is necessary for further bootstrapping and/or
where configuration management such as puppet or chef own dns configuration.
As Debian/Ubuntu will, by default, utilize resovlconf, and similarly RedHat
will use sysconfig, this module is likely to be of little use unless those
are configured correctly.
.. note::
For RedHat with sysconfig, be sure to set PEERDNS=no for all DHCP
enabled NICs.
.. note::
And, in Ubuntu/Debian it is recommended that DNS be configured via the
standard /etc/network/interfaces configuration file.
**Internal name:** ``cc_resolv_conf``
**Module frequency:** per instance
**Supported distros:** fedora, rhel, sles
**Config keys**::
manage_resolv_conf: <true/false>
resolv_conf:
nameservers: ['8.8.4.4', '8.8.8.8']
searchdomains:
- foo.example.com
- bar.example.com
domain: example.com
options:
rotate: <true/false>
timeout: 1
"""
from cloudinit import log as logging
from cloudinit.settings import PER_INSTANCE
from cloudinit import templater
from cloudinit import util
LOG = logging.getLogger(__name__)
frequency = PER_INSTANCE
distros = ['fedora', 'opensuse', 'rhel', 'sles']
def generate_resolv_conf(template_fn, params, target_fname="/etc/resolv.conf"):
flags = []
false_flags = []
if 'options' in params:
for key, val in params['options'].items():
if isinstance(val, bool):
if val:
flags.append(key)
else:
false_flags.append(key)
for flag in flags + false_flags:
del params['options'][flag]
if not params.get('options'):
params['options'] = {}
params['flags'] = flags
LOG.debug("Writing resolv.conf from template %s", template_fn)
templater.render_to_file(template_fn, target_fname, params)
def handle(name, cfg, cloud, log, _args):
"""
Handler for resolv.conf
@param name: The module name "resolv-conf" from cloud.cfg
@param cfg: A nested dict containing the entire cloud config contents.
@param cloud: The L{CloudInit} object in use.
@param log: Pre-initialized Python logger object to use for logging.
@param args: Any module arguments from cloud.cfg
"""
if "manage_resolv_conf" not in cfg:
log.debug(("Skipping module named %s,"
" no 'manage_resolv_conf' key in configuration"), name)
return
if not util.get_cfg_option_bool(cfg, "manage_resolv_conf", False):
log.debug(("Skipping module named %s,"
" 'manage_resolv_conf' present but set to False"), name)
return
if "resolv_conf" not in cfg:
log.warning("manage_resolv_conf True but no parameters provided!")
template_fn = cloud.get_template_filename('resolv.conf')
if not template_fn:
log.warning("No template found, not rendering /etc/resolv.conf")
return
generate_resolv_conf(template_fn=template_fn, params=cfg["resolv_conf"])
return
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