From d1790e6462e509e3cd87fc449df84fbd02ca1d89 Mon Sep 17 00:00:00 2001

From: Emanuele Giuseppe Esposito <eesposit@redhat.com>

Date: Thu, 2 Jun 2022 16:03:43 +0200

Subject: [PATCH 2/2] cc_set_hostname: do not write "localhost" when no

 hostname is given (#1453)

RH-Author: Emanuele Giuseppe Esposito <eesposit@redhat.com>

RH-MergeRequest: 28: cc_set_hostname: do not write "localhost" when no hostname is given (#1453)

RH-Commit: [1/1] 4370e9149371dc89be82cb05d30d33e4d2638cec (eesposit/cloud-init-centos-)

RH-Bugzilla: 1980403

RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

RH-Acked-by: Mohamed Gamal Morsy <mmorsy@redhat.com>

commit 74e43496f353db52e15d96abeb54ad63baac5be9

Author: Emanuele Giuseppe Esposito <eesposit@redhat.com>

Date:   Tue May 31 16:03:44 2022 +0200

    cc_set_hostname: do not write "localhost" when no hostname is given (#1453)

    Systemd used to sometimes ignore localhost in /etc/hostnames, and many programs

    like cloud-init used this as a workaround to set a default hostname.

    From https://github.com/systemd/systemd/commit/d39079fcaa05e23540d2b1f0270fa31c22a7e9f1:

            We would sometimes ignore localhost-style names in /etc/hostname. That is

            brittle. If the user configured some hostname, it's most likely because they

            want to use that as the hostname. If they don't want to use such a hostname,

            they should just not create the config. Everything becomes simples if we just

            use the configured hostname as-is.

            This behaviour seems to have been a workaround for Anaconda installer and other

            tools writing out /etc/hostname with the default of "localhost.localdomain".

            Anaconda PR to stop doing that: rhinstaller/anaconda#3040.

            That might have been useful as a work-around for other programs misbehaving if

            /etc/hostname was not present, but nowadays it's not useful because systemd

            mostly controls the hostname and it is perfectly happy without that file.

            Apart from making things simpler, this allows users to set a hostname like

            "localhost" and have it honoured, if such a whim strikes them.

    As also suggested by the Anaconda PR, we need to stop writing default "localhost"

    in /etc/hostnames, and let the right service (networking, user) do that if they

    need to. Otherwise, "localhost" will permanently stay as hostname and will

    prevent other tools like NetworkManager from setting the right one.

    Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

    RHBZ: 1980403

Conflicts:

	cloudinit/config/cc_update_etc_hosts.py

	cloudinit/sources/DataSourceCloudSigma.py

	cloudinit/util.py

	tests/unittests/test_util.py

	    Additional imports and/or conditionals that are not present in this version

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>

---

 cloudinit/cmd/main.py                         |  2 +-

 cloudinit/config/cc_apt_configure.py          |  2 +-

 cloudinit/config/cc_debug.py                  |  2 +-

 cloudinit/config/cc_phone_home.py             |  4 +-

 cloudinit/config/cc_set_hostname.py           |  6 ++-

 cloudinit/config/cc_spacewalk.py              |  2 +-

 cloudinit/config/cc_update_etc_hosts.py       |  4 +-

 cloudinit/config/cc_update_hostname.py        |  7 +++-

 cloudinit/sources/DataSourceAliYun.py         |  8 +++-

 cloudinit/sources/DataSourceCloudSigma.py     |  6 ++-

 cloudinit/sources/DataSourceGCE.py            |  5 ++-

 cloudinit/sources/DataSourceScaleway.py       |  3 +-

 cloudinit/sources/__init__.py                 | 28 ++++++++++---

 cloudinit/util.py                             | 29 +++++++++++---

 .../unittests/config/test_cc_set_hostname.py  | 40 ++++++++++++++++++-

 tests/unittests/sources/test_aliyun.py        |  2 +-

 tests/unittests/sources/test_cloudsigma.py    |  8 ++--

 tests/unittests/sources/test_digitalocean.py  |  2 +-

 tests/unittests/sources/test_gce.py           |  4 +-

 tests/unittests/sources/test_hetzner.py       |  2 +-

 tests/unittests/sources/test_init.py          | 29 +++++++++-----

 tests/unittests/sources/test_scaleway.py      |  2 +-

 tests/unittests/sources/test_vmware.py        |  4 +-

 tests/unittests/test_util.py                  | 17 ++++----

 tests/unittests/util.py                       |  3 +-

 25 files changed, 166 insertions(+), 55 deletions(-)

diff --git a/cloudinit/cmd/main.py b/cloudinit/cmd/main.py

index c9be41b3..816d31aa 100644

--- a/cloudinit/cmd/main.py

+++ b/cloudinit/cmd/main.py

@@ -813,7 +813,7 @@ def _maybe_set_hostname(init, stage, retry_stage):

     @param retry_stage: String represented logs upon error setting hostname.

     """

     cloud = init.cloudify()

-    (hostname, _fqdn) = util.get_hostname_fqdn(

+    (hostname, _fqdn, _) = util.get_hostname_fqdn(

         init.cfg, cloud, metadata_only=True

     )

     if hostname:  # meta-data or user-data hostname content

diff --git a/cloudinit/config/cc_apt_configure.py b/cloudinit/config/cc_apt_configure.py

index c558311a..0e6466ec 100644

--- a/cloudinit/config/cc_apt_configure.py

+++ b/cloudinit/config/cc_apt_configure.py

@@ -753,7 +753,7 @@ def search_for_mirror_dns(configured, mirrortype, cfg, cloud):

             raise ValueError("unknown mirror type")

         # if we have a fqdn, then search its domain portion first

-        (_, fqdn) = util.get_hostname_fqdn(cfg, cloud)

+        fqdn = util.get_hostname_fqdn(cfg, cloud).fqdn

         mydom = ".".join(fqdn.split(".")[1:])

         if mydom:

             doms.append(".%s" % mydom)

diff --git a/cloudinit/config/cc_debug.py b/cloudinit/config/cc_debug.py

index c51818c3..a00f2823 100644

--- a/cloudinit/config/cc_debug.py

+++ b/cloudinit/config/cc_debug.py

@@ -95,7 +95,7 @@ def handle(name, cfg, cloud, log, args):

         "Datasource: %s\n" % (type_utils.obj_name(cloud.datasource))

     )

     to_print.write("Distro: %s\n" % (type_utils.obj_name(cloud.distro)))

-    to_print.write("Hostname: %s\n" % (cloud.get_hostname(True)))

+    to_print.write("Hostname: %s\n" % (cloud.get_hostname(True).hostname))

     to_print.write("Instance ID: %s\n" % (cloud.get_instance_id()))

     to_print.write("Locale: %s\n" % (cloud.get_locale()))

     to_print.write("Launch IDX: %s\n" % (cloud.launch_index))

diff --git a/cloudinit/config/cc_phone_home.py b/cloudinit/config/cc_phone_home.py

index a0e1da78..1cf270aa 100644

--- a/cloudinit/config/cc_phone_home.py

+++ b/cloudinit/config/cc_phone_home.py

@@ -119,8 +119,8 @@ def handle(name, cfg, cloud, log, args):

     all_keys = {}

     all_keys["instance_id"] = cloud.get_instance_id()

-    all_keys["hostname"] = cloud.get_hostname()

-    all_keys["fqdn"] = cloud.get_hostname(fqdn=True)

+    all_keys["hostname"] = cloud.get_hostname().hostname

+    all_keys["fqdn"] = cloud.get_hostname(fqdn=True).hostname

     pubkeys = {

         "pub_key_dsa": "/etc/ssh/ssh_host_dsa_key.pub",

diff --git a/cloudinit/config/cc_set_hostname.py b/cloudinit/config/cc_set_hostname.py

index eb0ca328..2674fa20 100644

--- a/cloudinit/config/cc_set_hostname.py

+++ b/cloudinit/config/cc_set_hostname.py

@@ -76,7 +76,7 @@ def handle(name, cfg, cloud, log, _args):

     if hostname_fqdn is not None:

         cloud.distro.set_option("prefer_fqdn_over_hostname", hostname_fqdn)

-    (hostname, fqdn) = util.get_hostname_fqdn(cfg, cloud)

+    (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

@@ -94,6 +94,10 @@ def handle(name, cfg, cloud, log, _args):

     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)

diff --git a/cloudinit/config/cc_spacewalk.py b/cloudinit/config/cc_spacewalk.py

index 3fa6c388..419c8b32 100644

--- a/cloudinit/config/cc_spacewalk.py

+++ b/cloudinit/config/cc_spacewalk.py

@@ -89,7 +89,7 @@ def handle(name, cfg, cloud, log, _args):

         if not is_registered():

             do_register(

                 spacewalk_server,

-                cloud.datasource.get_hostname(fqdn=True),

+                cloud.datasource.get_hostname(fqdn=True).hostname,

                 proxy=cfg.get("proxy"),

                 log=log,

                 activation_key=cfg.get("activation_key"),

diff --git a/cloudinit/config/cc_update_etc_hosts.py b/cloudinit/config/cc_update_etc_hosts.py

index f0aa9b0f..d2ee6f45 100644

--- a/cloudinit/config/cc_update_etc_hosts.py

+++ b/cloudinit/config/cc_update_etc_hosts.py

@@ -62,7 +62,7 @@ def handle(name, cfg, cloud, log, _args):

     hosts_fn = cloud.distro.hosts_fn

     if util.translate_bool(manage_hosts, addons=["template"]):

-        (hostname, fqdn) = util.get_hostname_fqdn(cfg, cloud)

+        (hostname, fqdn, _) = util.get_hostname_fqdn(cfg, cloud)

         if not hostname:

             log.warning(

                 "Option 'manage_etc_hosts' was set, but no hostname was found"

@@ -84,7 +84,7 @@ def handle(name, cfg, cloud, log, _args):

         )

     elif manage_hosts == "localhost":

-        (hostname, fqdn) = util.get_hostname_fqdn(cfg, cloud)

+        (hostname, fqdn, _) = util.get_hostname_fqdn(cfg, cloud)

         if not hostname:

             log.warning(

                 "Option 'manage_etc_hosts' was set, but no hostname was found"

diff --git a/cloudinit/config/cc_update_hostname.py b/cloudinit/config/cc_update_hostname.py

index 09f6f6da..e2046020 100644

--- a/cloudinit/config/cc_update_hostname.py

+++ b/cloudinit/config/cc_update_hostname.py

@@ -56,7 +56,12 @@ def handle(name, cfg, cloud, log, _args):

     if hostname_fqdn is not None:

         cloud.distro.set_option("prefer_fqdn_over_hostname", hostname_fqdn)

-    (hostname, fqdn) = util.get_hostname_fqdn(cfg, cloud)

+    (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)

diff --git a/cloudinit/sources/DataSourceAliYun.py b/cloudinit/sources/DataSourceAliYun.py

index 37f512e3..b9390aca 100644

--- a/cloudinit/sources/DataSourceAliYun.py

+++ b/cloudinit/sources/DataSourceAliYun.py

@@ -2,6 +2,7 @@

 from cloudinit import dmi, sources

 from cloudinit.sources import DataSourceEc2 as EC2

+from cloudinit.sources import DataSourceHostname

 ALIYUN_PRODUCT = "Alibaba Cloud ECS"

@@ -16,7 +17,12 @@ class DataSourceAliYun(EC2.DataSourceEc2):

     extended_metadata_versions = []

     def get_hostname(self, fqdn=False, resolve_ip=False, metadata_only=False):

-        return self.metadata.get("hostname", "localhost.localdomain")

+        hostname = self.metadata.get("hostname")

+        is_default = False

+        if hostname is None:

+            hostname = "localhost.localdomain"

+            is_default = True

+        return DataSourceHostname(hostname, is_default)

     def get_public_ssh_keys(self):

         return parse_public_keys(self.metadata.get("public-keys", {}))

diff --git a/cloudinit/sources/DataSourceCloudSigma.py b/cloudinit/sources/DataSourceCloudSigma.py

index de71c3e9..91ebb084 100644

--- a/cloudinit/sources/DataSourceCloudSigma.py

+++ b/cloudinit/sources/DataSourceCloudSigma.py

@@ -11,6 +11,7 @@ from cloudinit import dmi

 from cloudinit import log as logging

 from cloudinit import sources

 from cloudinit.cs_utils import SERIAL_PORT, Cepko

+from cloudinit.sources import DataSourceHostname

 LOG = logging.getLogger(__name__)

@@ -90,9 +91,10 @@ class DataSourceCloudSigma(sources.DataSource):

         the first part from uuid is being used.

         """

         if re.match(r"^[A-Za-z0-9 -_\.]+$", self.metadata["name"]):

-            return self.metadata["name"][:61]

+            ret = self.metadata["name"][:61]

         else:

-            return self.metadata["uuid"].split("-")[0]

+            ret = self.metadata["uuid"].split("-")[0]

+        return DataSourceHostname(ret, False)

     def get_public_ssh_keys(self):

         return [self.ssh_public_key]

diff --git a/cloudinit/sources/DataSourceGCE.py b/cloudinit/sources/DataSourceGCE.py

index c470bea8..f7ec6b52 100644

--- a/cloudinit/sources/DataSourceGCE.py

+++ b/cloudinit/sources/DataSourceGCE.py

@@ -12,6 +12,7 @@ from cloudinit import log as logging

 from cloudinit import sources, url_helper, util

 from cloudinit.distros import ug_util

 from cloudinit.net.dhcp import EphemeralDHCPv4

+from cloudinit.sources import DataSourceHostname

 LOG = logging.getLogger(__name__)

@@ -122,7 +123,9 @@ class DataSourceGCE(sources.DataSource):

     def get_hostname(self, fqdn=False, resolve_ip=False, metadata_only=False):

         # GCE has long FDQN's and has asked for short hostnames.

-        return self.metadata["local-hostname"].split(".")[0]

+        return DataSourceHostname(

+            self.metadata["local-hostname"].split(".")[0], False

+        )

     @property

     def availability_zone(self):

diff --git a/cloudinit/sources/DataSourceScaleway.py b/cloudinit/sources/DataSourceScaleway.py

index 8e5dd82c..8f08dc6d 100644

--- a/cloudinit/sources/DataSourceScaleway.py

+++ b/cloudinit/sources/DataSourceScaleway.py

@@ -30,6 +30,7 @@ from cloudinit import log as logging

 from cloudinit import net, sources, url_helper, util

 from cloudinit.event import EventScope, EventType

 from cloudinit.net.dhcp import EphemeralDHCPv4, NoDHCPLeaseError

+from cloudinit.sources import DataSourceHostname

 LOG = logging.getLogger(__name__)

@@ -282,7 +283,7 @@ class DataSourceScaleway(sources.DataSource):

         return ssh_keys

     def get_hostname(self, fqdn=False, resolve_ip=False, metadata_only=False):

-        return self.metadata["hostname"]

+        return DataSourceHostname(self.metadata["hostname"], False)

     @property

     def availability_zone(self):

diff --git a/cloudinit/sources/__init__.py b/cloudinit/sources/__init__.py

index 88028cfa..77b24fd7 100644

--- a/cloudinit/sources/__init__.py

+++ b/cloudinit/sources/__init__.py

@@ -148,6 +148,11 @@ URLParams = namedtuple(

     ],

 )

+DataSourceHostname = namedtuple(

+    "DataSourceHostname",

+    ["hostname", "is_default"],

+)

+

 class DataSource(CloudInitPickleMixin, metaclass=abc.ABCMeta):

@@ -291,7 +296,7 @@ class DataSource(CloudInitPickleMixin, metaclass=abc.ABCMeta):

     def _get_standardized_metadata(self, instance_data):

         """Return a dictionary of standardized metadata keys."""

-        local_hostname = self.get_hostname()

+        local_hostname = self.get_hostname().hostname

         instance_id = self.get_instance_id()

         availability_zone = self.availability_zone

         # In the event of upgrade from existing cloudinit, pickled datasource

@@ -697,22 +702,33 @@ class DataSource(CloudInitPickleMixin, metaclass=abc.ABCMeta):

         @param metadata_only: Boolean, set True to avoid looking up hostname

             if meta-data doesn't have local-hostname present.

-        @return: hostname or qualified hostname. Optionally return None when

+        @return: a DataSourceHostname namedtuple

+            <hostname or qualified hostname>, <is_default> (str, bool).

+            is_default is a bool and

+            it's true only if hostname is localhost and was

+            returned by util.get_hostname() as a default.

+            This is used to differentiate with a user-defined

+            localhost hostname.

+            Optionally return (None, False) when

             metadata_only is True and local-hostname data is not available.

         """

         defdomain = "localdomain"

         defhost = "localhost"

         domain = defdomain

+        is_default = False

         if not self.metadata or not self.metadata.get("local-hostname"):

             if metadata_only:

-                return None

+                return DataSourceHostname(None, is_default)

             # this is somewhat questionable really.

             # the cloud datasource was asked for a hostname

             # and didn't have one. raising error might be more appropriate

             # but instead, basically look up the existing hostname

             toks = []

             hostname = util.get_hostname()

+            if hostname == "localhost":

+                # default hostname provided by socket.gethostname()

+                is_default = True

             hosts_fqdn = util.get_fqdn_from_hosts(hostname)

             if hosts_fqdn and hosts_fqdn.find(".") > 0:

                 toks = str(hosts_fqdn).split(".")

@@ -745,9 +761,9 @@ class DataSource(CloudInitPickleMixin, metaclass=abc.ABCMeta):

             hostname = toks[0]

         if fqdn and domain != defdomain:

-            return "%s.%s" % (hostname, domain)

-        else:

-            return hostname

+            hostname = "%s.%s" % (hostname, domain)

+

+        return DataSourceHostname(hostname, is_default)

     def get_package_mirror_info(self):

         return self.distro.get_package_mirror_info(data_source=self)

diff --git a/cloudinit/util.py b/cloudinit/util.py

index 569fc215..4cb21551 100644

--- a/cloudinit/util.py

+++ b/cloudinit/util.py

@@ -32,7 +32,8 @@ import subprocess

 import sys

 import time

 from base64 import b64decode, b64encode

-from errno import ENOENT

+from collections import deque, namedtuple

+from errno import EACCES, ENOENT

 from functools import lru_cache

 from typing import List

 from urllib import parse

@@ -1072,6 +1073,12 @@ def dos2unix(contents):

     return contents.replace("\r\n", "\n")

+HostnameFqdnInfo = namedtuple(

+    "HostnameFqdnInfo",

+    ["hostname", "fqdn", "is_default"],

+)

+

+

 def get_hostname_fqdn(cfg, cloud, metadata_only=False):

     """Get hostname and fqdn from config if present and fallback to cloud.

@@ -1079,9 +1086,17 @@ def get_hostname_fqdn(cfg, cloud, metadata_only=False):

     @param cloud: Cloud instance from init.cloudify().

     @param metadata_only: Boolean, set True to only query cloud meta-data,

         returning None if not present in meta-data.

-    @return: a Tuple of strings <hostname>, <fqdn>. Values can be none when

+    @return: a namedtuple of

+        <hostname>, <fqdn>, <is_default> (str, str, bool).

+        Values can be none when

         metadata_only is True and no cfg or metadata provides hostname info.

+        is_default is a bool and

+        it's true only if hostname is localhost and was

+        returned by util.get_hostname() as a default.

+        This is used to differentiate with a user-defined

+        localhost hostname.

     """

+    is_default = False

     if "fqdn" in cfg:

         # user specified a fqdn.  Default hostname then is based off that

         fqdn = cfg["fqdn"]

@@ -1095,12 +1110,16 @@ def get_hostname_fqdn(cfg, cloud, metadata_only=False):

         else:

             # no fqdn set, get fqdn from cloud.

             # get hostname from cfg if available otherwise cloud

-            fqdn = cloud.get_hostname(fqdn=True, metadata_only=metadata_only)

+            fqdn = cloud.get_hostname(

+                fqdn=True, metadata_only=metadata_only

+            ).hostname

             if "hostname" in cfg:

                 hostname = cfg["hostname"]

             else:

-                hostname = cloud.get_hostname(metadata_only=metadata_only)

-    return (hostname, fqdn)

+                hostname, is_default = cloud.get_hostname(

+                    metadata_only=metadata_only

+                )

+    return HostnameFqdnInfo(hostname, fqdn, is_default)

 def get_fqdn_from_hosts(hostname, filename="/etc/hosts"):

diff --git a/tests/unittests/config/test_cc_set_hostname.py b/tests/unittests/config/test_cc_set_hostname.py

index fd994c4e..3d1d86ee 100644

--- a/tests/unittests/config/test_cc_set_hostname.py

+++ b/tests/unittests/config/test_cc_set_hostname.py

@@ -11,6 +11,7 @@ from configobj import ConfigObj

 from cloudinit import cloud, distros, helpers, util

 from cloudinit.config import cc_set_hostname

+from cloudinit.sources import DataSourceNone

 from tests.unittests import helpers as t_help

 LOG = logging.getLogger(__name__)

@@ -153,7 +154,8 @@ class TestHostname(t_help.FilesystemMockingTestCase):

                     )

                 ] not in m_subp.call_args_list

-    def test_multiple_calls_skips_unchanged_hostname(self):

+    @mock.patch("cloudinit.util.get_hostname", return_value="localhost")

+    def test_multiple_calls_skips_unchanged_hostname(self, get_hostname):

         """Only new hostname or fqdn values will generate a hostname call."""

         distro = self._fetch_distro("debian")

         paths = helpers.Paths({"cloud_dir": self.tmp})

@@ -182,6 +184,42 @@ class TestHostname(t_help.FilesystemMockingTestCase):

             self.logs.getvalue(),

         )

+    @mock.patch("cloudinit.util.get_hostname", return_value="localhost")

+    def test_localhost_default_hostname(self, get_hostname):

+        """

+        No hostname set. Default value returned is localhost,

+        but we shouldn't write it in /etc/hostname

+        """

+        distro = self._fetch_distro("debian")

+        paths = helpers.Paths({"cloud_dir": self.tmp})

+        ds = DataSourceNone.DataSourceNone({}, None, paths)

+        cc = cloud.Cloud(ds, paths, {}, distro, None)

+        self.patchUtils(self.tmp)

+

+        util.write_file("/etc/hostname", "")

+        cc_set_hostname.handle("cc_set_hostname", {}, cc, LOG, [])

+        contents = util.load_file("/etc/hostname")

+        self.assertEqual("", contents.strip())

+

+    @mock.patch("cloudinit.util.get_hostname", return_value="localhost")

+    def test_localhost_user_given_hostname(self, get_hostname):

+        """

+        User set hostname is localhost. We should write it in /etc/hostname

+        """

+        distro = self._fetch_distro("debian")

+        paths = helpers.Paths({"cloud_dir": self.tmp})

+        ds = DataSourceNone.DataSourceNone({}, None, paths)

+        cc = cloud.Cloud(ds, paths, {}, distro, None)

+        self.patchUtils(self.tmp)

+

+        # user-provided localhost should not be ignored

+        util.write_file("/etc/hostname", "")

+        cc_set_hostname.handle(

+            "cc_set_hostname", {"hostname": "localhost"}, cc, LOG, []

+        )

+        contents = util.load_file("/etc/hostname")

+        self.assertEqual("localhost", contents.strip())

+

     def test_error_on_distro_set_hostname_errors(self):

         """Raise SetHostnameError on exceptions from distro.set_hostname."""

         distro = self._fetch_distro("debian")

diff --git a/tests/unittests/sources/test_aliyun.py b/tests/unittests/sources/test_aliyun.py

index 8a61d5ee..e628dc02 100644

--- a/tests/unittests/sources/test_aliyun.py

+++ b/tests/unittests/sources/test_aliyun.py

@@ -149,7 +149,7 @@ class TestAliYunDatasource(test_helpers.HttprettyTestCase):

     def _test_host_name(self):

         self.assertEqual(

-            self.default_metadata["hostname"], self.ds.get_hostname()

+            self.default_metadata["hostname"], self.ds.get_hostname().hostname

         )

     @mock.patch("cloudinit.sources.DataSourceAliYun._is_aliyun")

diff --git a/tests/unittests/sources/test_cloudsigma.py b/tests/unittests/sources/test_cloudsigma.py

index a2f26245..3dca7ea8 100644

--- a/tests/unittests/sources/test_cloudsigma.py

+++ b/tests/unittests/sources/test_cloudsigma.py

@@ -58,12 +58,14 @@ class DataSourceCloudSigmaTest(test_helpers.CiTestCase):

     def test_get_hostname(self):

         self.datasource.get_data()

-        self.assertEqual("test_server", self.datasource.get_hostname())

+        self.assertEqual(

+            "test_server", self.datasource.get_hostname().hostname

+        )

         self.datasource.metadata["name"] = ""

-        self.assertEqual("65b2fb23", self.datasource.get_hostname())

+        self.assertEqual("65b2fb23", self.datasource.get_hostname().hostname)

         utf8_hostname = b"\xd1\x82\xd0\xb5\xd1\x81\xd1\x82".decode("utf-8")

         self.datasource.metadata["name"] = utf8_hostname

-        self.assertEqual("65b2fb23", self.datasource.get_hostname())

+        self.assertEqual("65b2fb23", self.datasource.get_hostname().hostname)

     def test_get_public_ssh_keys(self):

         self.datasource.get_data()

diff --git a/tests/unittests/sources/test_digitalocean.py b/tests/unittests/sources/test_digitalocean.py

index f3e6224e..47e46c66 100644

--- a/tests/unittests/sources/test_digitalocean.py

+++ b/tests/unittests/sources/test_digitalocean.py

@@ -178,7 +178,7 @@ class TestDataSourceDigitalOcean(CiTestCase):

         self.assertEqual(DO_META.get("vendor_data"), ds.get_vendordata_raw())

         self.assertEqual(DO_META.get("region"), ds.availability_zone)

         self.assertEqual(DO_META.get("droplet_id"), ds.get_instance_id())

-        self.assertEqual(DO_META.get("hostname"), ds.get_hostname())

+        self.assertEqual(DO_META.get("hostname"), ds.get_hostname().hostname)

         # Single key

         self.assertEqual(

diff --git a/tests/unittests/sources/test_gce.py b/tests/unittests/sources/test_gce.py

index e030931b..1ce0c6ec 100644

--- a/tests/unittests/sources/test_gce.py

+++ b/tests/unittests/sources/test_gce.py

@@ -126,7 +126,7 @@ class TestDataSourceGCE(test_helpers.HttprettyTestCase):

         self.ds.get_data()

         shostname = GCE_META.get("instance/hostname").split(".")[0]

-        self.assertEqual(shostname, self.ds.get_hostname())

+        self.assertEqual(shostname, self.ds.get_hostname().hostname)

         self.assertEqual(

             GCE_META.get("instance/id"), self.ds.get_instance_id()

@@ -147,7 +147,7 @@ class TestDataSourceGCE(test_helpers.HttprettyTestCase):

         )

         shostname = GCE_META_PARTIAL.get("instance/hostname").split(".")[0]

-        self.assertEqual(shostname, self.ds.get_hostname())

+        self.assertEqual(shostname, self.ds.get_hostname().hostname)

     def test_userdata_no_encoding(self):

         """check that user-data is read."""

diff --git a/tests/unittests/sources/test_hetzner.py b/tests/unittests/sources/test_hetzner.py

index f80ed45f..193b7e42 100644

--- a/tests/unittests/sources/test_hetzner.py

+++ b/tests/unittests/sources/test_hetzner.py

@@ -116,7 +116,7 @@ class TestDataSourceHetzner(CiTestCase):

         self.assertTrue(m_readmd.called)

-        self.assertEqual(METADATA.get("hostname"), ds.get_hostname())

+        self.assertEqual(METADATA.get("hostname"), ds.get_hostname().hostname)

         self.assertEqual(METADATA.get("public-keys"), ds.get_public_ssh_keys())

diff --git a/tests/unittests/sources/test_init.py b/tests/unittests/sources/test_init.py

index ce8fc970..79fc9c5b 100644

--- a/tests/unittests/sources/test_init.py

+++ b/tests/unittests/sources/test_init.py

@@ -272,9 +272,11 @@ class TestDataSource(CiTestCase):

         self.assertEqual(

             "test-subclass-hostname", datasource.metadata["local-hostname"]

         )

-        self.assertEqual("test-subclass-hostname", datasource.get_hostname())

+        self.assertEqual(

+            "test-subclass-hostname", datasource.get_hostname().hostname

+        )

         datasource.metadata["local-hostname"] = "hostname.my.domain.com"

-        self.assertEqual("hostname", datasource.get_hostname())

+        self.assertEqual("hostname", datasource.get_hostname().hostname)

     def test_get_hostname_with_fqdn_returns_local_hostname_with_domain(self):

         """Datasource.get_hostname with fqdn set gets qualified hostname."""

@@ -285,7 +287,8 @@ class TestDataSource(CiTestCase):

         self.assertTrue(datasource.get_data())

         datasource.metadata["local-hostname"] = "hostname.my.domain.com"

         self.assertEqual(

-            "hostname.my.domain.com", datasource.get_hostname(fqdn=True)

+            "hostname.my.domain.com",

+            datasource.get_hostname(fqdn=True).hostname,

         )

     def test_get_hostname_without_metadata_uses_system_hostname(self):

@@ -300,10 +303,12 @@ class TestDataSource(CiTestCase):

             with mock.patch(mock_fqdn) as m_fqdn:

                 m_gethost.return_value = "systemhostname.domain.com"

                 m_fqdn.return_value = None  # No maching fqdn in /etc/hosts

-                self.assertEqual("systemhostname", datasource.get_hostname())

+                self.assertEqual(

+                    "systemhostname", datasource.get_hostname().hostname

+                )

                 self.assertEqual(

                     "systemhostname.domain.com",

-                    datasource.get_hostname(fqdn=True),

+                    datasource.get_hostname(fqdn=True).hostname,

                 )

     def test_get_hostname_without_metadata_returns_none(self):

@@ -316,9 +321,13 @@ class TestDataSource(CiTestCase):

         mock_fqdn = "cloudinit.sources.util.get_fqdn_from_hosts"

         with mock.patch("cloudinit.sources.util.get_hostname") as m_gethost:

             with mock.patch(mock_fqdn) as m_fqdn:

-                self.assertIsNone(datasource.get_hostname(metadata_only=True))

                 self.assertIsNone(

-                    datasource.get_hostname(fqdn=True, metadata_only=True)

+                    datasource.get_hostname(metadata_only=True).hostname

+                )

+                self.assertIsNone(

+                    datasource.get_hostname(

+                        fqdn=True, metadata_only=True

+                    ).hostname

                 )

         self.assertEqual([], m_gethost.call_args_list)

         self.assertEqual([], m_fqdn.call_args_list)

@@ -335,10 +344,12 @@ class TestDataSource(CiTestCase):

             with mock.patch(mock_fqdn) as m_fqdn:

                 m_gethost.return_value = "systemhostname.domain.com"

                 m_fqdn.return_value = "fqdnhostname.domain.com"

-                self.assertEqual("fqdnhostname", datasource.get_hostname())

+                self.assertEqual(

+                    "fqdnhostname", datasource.get_hostname().hostname

+                )

                 self.assertEqual(

                     "fqdnhostname.domain.com",

-                    datasource.get_hostname(fqdn=True),

+                    datasource.get_hostname(fqdn=True).hostname,

                 )

     def test_get_data_does_not_write_instance_data_on_failure(self):

diff --git a/tests/unittests/sources/test_scaleway.py b/tests/unittests/sources/test_scaleway.py

index d7e8b969..56735dd0 100644

--- a/tests/unittests/sources/test_scaleway.py

+++ b/tests/unittests/sources/test_scaleway.py

@@ -236,7 +236,7 @@ class TestDataSourceScaleway(HttprettyTestCase):

             ].sort(),

         )

         self.assertEqual(

-            self.datasource.get_hostname(),

+            self.datasource.get_hostname().hostname,

             MetadataResponses.FAKE_METADATA["hostname"],

         )

         self.assertEqual(

diff --git a/tests/unittests/sources/test_vmware.py b/tests/unittests/sources/test_vmware.py

index dd331349..753bb774 100644

--- a/tests/unittests/sources/test_vmware.py

+++ b/tests/unittests/sources/test_vmware.py

@@ -368,7 +368,9 @@ class TestDataSourceVMwareGuestInfo_InvalidPlatform(FilesystemMockingTestCase):

 def assert_metadata(test_obj, ds, metadata):

     test_obj.assertEqual(metadata.get("instance-id"), ds.get_instance_id())

-    test_obj.assertEqual(metadata.get("local-hostname"), ds.get_hostname())

+    test_obj.assertEqual(

+        metadata.get("local-hostname"), ds.get_hostname().hostname

+    )

     expected_public_keys = metadata.get("public_keys")

     if not isinstance(expected_public_keys, list):

diff --git a/tests/unittests/test_util.py b/tests/unittests/test_util.py

index 3765511b..528b7f36 100644

--- a/tests/unittests/test_util.py

+++ b/tests/unittests/test_util.py

@@ -19,6 +19,7 @@ import pytest

 import yaml

 from cloudinit import importer, subp, util

+from cloudinit.sources import DataSourceHostname

 from tests.unittests import helpers

 from tests.unittests.helpers import CiTestCase

@@ -331,8 +332,8 @@ class FakeCloud(object):

             myargs["metadata_only"] = metadata_only

         self.calls.append(myargs)

         if fqdn:

-            return self.fqdn