name : cc_resolv_conf.py # 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: configure resolv.conf""" import logging from textwrap import dedent from cloudinit import templater, util from cloudinit.cloud import Cloud from cloudinit.config import Config from cloudinit.config.schema import MetaSchema, get_meta_doc from cloudinit.settings import PER_INSTANCE LOG = logging.getLogger(__name__) RESOLVE_CONFIG_TEMPLATE_MAP = { "/etc/resolv.conf": "resolv.conf", "/etc/systemd/resolved.conf": "systemd.resolved.conf", } MODULE_DESCRIPTION = """\ Unless manually editing :file:`/etc/resolv.conf` is the correct way to manage nameserver information on your operating system, you do not want to use this module. Many distros have moved away from manually editing ``resolv.conf`` so please verify that this is the preferred nameserver management method for your distro before using this module. Note that using :ref:`network_config` is preferred, rather than using this module, when possible. 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. When using a :ref:`datasource_config_drive` and a RHEL-like system, resolv.conf will also be managed automatically due to the available information provided for DNS servers in the :ref:`network_config_v2` format. For those that wish to have different settings, use this module. In order for the ``resolv_conf`` section to be applied, ``manage_resolv_conf`` must be set ``true``. .. note:: For Red Hat with sysconfig, be sure to set PEERDNS=no for all DHCP enabled NICs. """ meta: MetaSchema = { "id": "cc_resolv_conf", "name": "Resolv Conf", "title": "Configure resolv.conf", "description": MODULE_DESCRIPTION, "distros": [ "alpine", "fedora", "mariner", "opensuse", "opensuse-leap", "opensuse-microos", "opensuse-tumbleweed", "photon", "rhel", "sle_hpc", "sle-micro", "sles", "openeuler", ], "frequency": PER_INSTANCE, "examples": [ dedent( """\ manage_resolv_conf: true resolv_conf: nameservers: - 8.8.8.8 - 8.8.4.4 searchdomains: - foo.example.com - bar.example.com domain: example.com sortlist: - 10.0.0.1/255 - 10.0.0.2 options: rotate: true timeout: 1 """ ) ], "activate_by_schema_keys": ["manage_resolv_conf"], } __doc__ = get_meta_doc(meta) def generate_resolv_conf(template_fn, params, target_fname): 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: str, cfg: Config, cloud: Cloud, args: list) -> None: """ 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!") return try: template_fn = cloud.get_template_filename( RESOLVE_CONFIG_TEMPLATE_MAP[cloud.distro.resolve_conf_fn] ) except KeyError: LOG.warning("No template found, not rendering resolve configs") return generate_resolv_conf( template_fn=template_fn, params=cfg["resolv_conf"], target_fname=cloud.distro.resolve_conf_fn, ) return