apply: restart networkd instead of reload/reconfigure

Due to systemd-networkd bugs, reload/reconfigure was not working in
some cases. Instead, restart the service if the configuration has
changed (LP#2058976).

netplan_cli/cli/commands/apply.py

@@ -273,15 +273,20 @@ def command_apply(self, run_generate=True, sync=False, exit_on_error=True, state
             # exclude the special 'netplan-ovs-cleanup.service' unit
             netplan_ovs = [os.path.basename(f) for f in glob.glob('/run/systemd/system/*.wants/netplan-ovs-*.service')
                            if not f.endswith('/' + OVS_CLEANUP_SERVICE)]
-            # Run 'systemctl start' command synchronously, to avoid race conditions
+            # Run 'systemctl (re)start' command synchronously, to avoid race conditions
             # with 'oneshot' systemd service units, e.g. netplan-ovs-*.service.
-            try:
-                utils.networkctl_reload()
-                utils.networkctl_reconfigure(utils.networkd_interfaces())
-            except subprocess.CalledProcessError:
-                # (re-)start systemd-networkd if it is not running, yet
-                logging.warning('Falling back to a hard restart of systemd-networkd.service')
-                utils.systemctl('restart', ['systemd-networkd.service'], sync=True)
+            #
+            # In the past, calls to networkctl_reload/networkctl_reconfigure
+            # were tried, but due maybe to systemd-networkd bugs, they were not
+            # working as expected: the interface was getting initially the
+            # expected state, but after some minutes it ignored the state of
+            # /run/systemd/network/ and used the configuration read when the
+            # service was started. This happened in the case of removed
+            # .network files. Looking at files in
+            # /run/systemd/netif/links/<num>, the internal state seemed to keep
+            # removed files in NETWORK_FILE= (see LP#2058976).
+            logging.info('Restarting systemd-networkd.service')
+            utils.systemctl('restart', ['systemd-networkd.service'], sync=True)
             # 1st: execute OVS cleanup, to avoid races while applying OVS config
             utils.systemctl('start', [OVS_CLEANUP_SERVICE], sync=True)
             # 2nd: start all other services