CasperSecurity
# 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.
"""Set Hostname: Set hostname and FQDN"""
import logging
import os
from cloudinit import util
from cloudinit.atomic_helper import write_json
from cloudinit.cloud import Cloud
from cloudinit.config import Config
from cloudinit.config.schema import MetaSchema
from cloudinit.distros import ALL_DISTROS
from cloudinit.settings import PER_INSTANCE
meta: MetaSchema = {
"id": "cc_set_hostname",
"distros": [ALL_DISTROS],
"frequency": PER_INSTANCE,
"activate_by_schema_keys": [],
}
LOG = logging.getLogger(__name__)
class SetHostnameError(Exception):
"""Raised when the distro runs into an exception when setting hostname.
This may happen if we attempt to set the hostname early in cloud-init's
init-local timeframe as certain services may not be running yet.
"""
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 setting 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)
# Check for previous successful invocation of set_hostname
# set-hostname artifact file accounts for both hostname and fqdn
# deltas. As such, it's format is different than cc_update_hostname's
# previous-hostname file which only contains the base hostname.
# TODO consolidate previous-hostname and set-hostname artifact files and
# distro._read_hostname implementation so we only validate one artifact.
prev_fn = os.path.join(cloud.get_cpath("data"), "set-hostname")
prev_hostname = {}
if os.path.exists(prev_fn) and os.stat(prev_fn).st_size > 0:
prev_hostname = util.load_json(util.load_text_file(prev_fn))
hostname_changed = hostname != prev_hostname.get(
"hostname"
) or fqdn != prev_hostname.get("fqdn")
if not hostname_changed:
LOG.debug("No hostname changes. Skipping set_hostname")
return
if is_default and hostname == "localhost":
# https://github.com/systemd/systemd/commit/d39079fcaa05e23540d2b1f0270fa31c22a7e9f1
LOG.debug("Hostname is localhost. Let other services handle this.")
return
LOG.debug("Setting the hostname to %s (%s)", fqdn, hostname)
try:
cloud.distro.set_hostname(hostname, fqdn)
except Exception as e:
msg = "Failed to set the hostname to %s (%s)" % (fqdn, hostname)
util.logexc(LOG, msg)
raise SetHostnameError("%s: %s" % (msg, e)) from e
write_json(prev_fn, {"hostname": hostname, "fqdn": fqdn})