Implement ntp client spec with auto support for distro selection

Add a base NTP client configuration dictionary and allow Distro
specific changes to be merged.  Add a select client function which
implements logic to preferr installed clients over clients which
need to be installed.  Also allow distributions to override the
cloud-init defaults.

LP: #1749722

1 files changed, 19 insertions, 0 deletions

diff --git a/cloudinit/distros/ubuntu.py b/cloudinit/distros/ubuntu.py
index 82ca34f5..fdc1f622 100644
--- a/cloudinit/distros/ubuntu.py
+++ b/cloudinit/distros/ubuntu.py
@@ -10,12 +10,31 @@
 # This file is part of cloud-init. See LICENSE file for license information.
 
 from cloudinit.distros import debian
+from cloudinit.distros import PREFERRED_NTP_CLIENTS
 from cloudinit import log as logging
+from cloudinit import util
+
+import copy
 
 LOG = logging.getLogger(__name__)
 
 
 class Distro(debian.Distro):
+
+    @property
+    def preferred_ntp_clients(self):
+        """The preferred ntp client is dependent on the version."""
+        if not self._preferred_ntp_clients:
+            (name, version, codename) = util.system_info()['dist']
+            # Xenial cloud-init only installed ntp, UbuntuCore has timesyncd.
+            if codename == "xenial" and not util.system_is_snappy():
+                self._preferred_ntp_clients = ['ntp']
+            else:
+                self._preferred_ntp_clients = (
+                    copy.deepcopy(PREFERRED_NTP_CLIENTS))
+        return self._preferred_ntp_clients
+
     pass
 
+
 # vi: ts=4 expandtab