name : cc_update_hostname.py # Copyright (C) 2011 Canonical Ltd. # Copyright (C) 2012, 2013 Hewlett-Packard Development Company, L.P. # # Author: Scott Moser <scott.moser@canonical.com> # Author: Juerg Haefliger <juerg.haefliger@hp.com> # # This file is part of cloud-init. See LICENSE file for license information. """Update Hostname: Update hostname and fqdn""" import logging import os from textwrap import dedent from cloudinit import 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_ALWAYS MODULE_DESCRIPTION = """\ This module will update the system hostname and fqdn. If ``preserve_hostname`` is set ``true``, then the hostname will not be altered. .. note:: for instructions on specifying hostname and fqdn, see documentation for ``cc_set_hostname`` """ distros = ["all"] meta: MetaSchema = { "id": "cc_update_hostname", "name": "Update Hostname", "title": "Update hostname and fqdn", "description": MODULE_DESCRIPTION, "distros": distros, "examples": [ dedent( """\ # By default: when ``preserve_hostname`` is not specified cloud-init # updates ``/etc/hostname`` per-boot based on the cloud provided # ``local-hostname`` setting. If you manually change ``/etc/hostname`` # after boot cloud-init will no longer modify it. # # This default cloud-init behavior is equivalent to this cloud-config: preserve_hostname: false """ ), dedent( """\ # Prevent cloud-init from updating the system hostname. preserve_hostname: true """ ), dedent( """\ # Prevent cloud-init from updating ``/etc/hostname`` preserve_hostname: true """ ), dedent( """\ # Set hostname to "external.fqdn.me" instead of "myhost" fqdn: external.fqdn.me hostname: myhost prefer_fqdn_over_hostname: true create_hostname_file: true """ ), dedent( """\ # Set hostname to "external" instead of "external.fqdn.me" when # cloud metadata provides the ``local-hostname``: "external.fqdn.me". prefer_fqdn_over_hostname: false """ ), dedent( """\ # On a machine without an ``/etc/hostname`` file, don't create it # In most clouds, this will result in a DHCP-configured hostname # provided by the cloud create_hostname_file: false """ ), ], "frequency": PER_ALWAYS, "activate_by_schema_keys": [], } __doc__ = get_meta_doc(meta) LOG = logging.getLogger(__name__) def handle(name: str, cfg: Config, cloud: Cloud, args: list) -> None: if util.get_cfg_option_bool(cfg, "preserve_hostname", False): LOG.debug( "Configuration option 'preserve_hostname' is set," " not updating the hostname in module %s", name, ) return # Set prefer_fqdn_over_hostname value in distro hostname_fqdn = util.get_cfg_option_bool( cfg, "prefer_fqdn_over_hostname", None ) if hostname_fqdn is not None: cloud.distro.set_option("prefer_fqdn_over_hostname", hostname_fqdn) # Set create_hostname_file in distro create_hostname_file = util.get_cfg_option_bool( cfg, "create_hostname_file", None ) if create_hostname_file is not None: cloud.distro.set_option("create_hostname_file", create_hostname_file) (hostname, fqdn, is_default) = util.get_hostname_fqdn(cfg, cloud) if is_default and hostname == "localhost": # https://github.com/systemd/systemd/commit/d39079fcaa05e23540d2b1f0270fa31c22a7e9f1 LOG.debug("Hostname is localhost. Let other services handle this.") return try: prev_fn = os.path.join(cloud.get_cpath("data"), "previous-hostname") LOG.debug("Updating hostname to %s (%s)", fqdn, hostname) cloud.distro.update_hostname(hostname, fqdn, prev_fn) except Exception: util.logexc( LOG, "Failed to update the hostname to %s (%s)", fqdn, hostname ) raise