# Copyright (C) 2013 Craig Tracey # Copyright (C) 2013 Hewlett-Packard Development Company, L.P. # # Author: Craig Tracey # Author: Juerg Haefliger # # 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: resolv_conf: nameservers: ['8.8.4.4', '8.8.8.8'] searchdomains: - foo.example.com - bar.example.com domain: example.com options: rotate: 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 # vi: ts=4 expandtab