cli:apply: add comment about udevadm trigger errors

Author: slyon

netplan_cli/cli/commands/apply.py

@@ -256,6 +256,8 @@ def command_apply(self, run_generate=True, sync=False, exit_on_error=True, state
         try:
             subprocess.check_call(['udevadm', 'trigger', '--action=move', '--subsystem-match=net', '--settle'])
         except subprocess.CalledProcessError as e:
+            # udevadm trigger returns 1 if it cannot trigger devices since
+            # systemd v248, e.g. in containers (LP: #2095203)
             logging.warning('Ignoring device trigger error: {}'.format(e))
 
         # apply any SR-IOV related changes, if applicable