feat: Warn user of unexpected run mode

cloudinit/cmd/main.py

@@ -72,17 +72,21 @@ def print_exc(msg=""):
     sys.stderr.write("\n")
 
 
-def log_ppid():
-    if util.is_Linux():
+def log_ppid(distro):
+    if distro.is_linux:
         ppid = os.getppid()
-        LOG.info("PID [%s] started cloud-init.", ppid)
+        log = LOG.info
+        extra_message = ""
+        if 1 != ppid and distro.uses_systemd():
+            log = LOG.warning
+            extra_message = ("Not a supported configuration.",)
+        log("PID [%s] started cloud-init. %s", ppid, extra_message)
 
 
 def welcome(action, msg=None):
     if not msg:
         msg = welcome_format(action)
     util.multi_log("%s\n" % (msg), console=False, stderr=True, log=LOG)
-    log_ppid()
     return msg
 
 
@@ -324,6 +328,7 @@ def main_init(name, args):
     init = stages.Init(ds_deps=deps, reporter=args.reporter)
     # Stage 1
     init.read_cfg(extract_fns(args))
+    log_ppid(init.distro)
     # Stage 2
     outfmt = None
     errfmt = None
@@ -580,6 +585,7 @@ def main_modules(action_name, args):
     init = stages.Init(ds_deps=[], reporter=args.reporter)
     # Stage 1
     init.read_cfg(extract_fns(args))
+    log_ppid(init.distro)
     # Stage 2
     try:
         init.fetch(existing="trust")

cloudinit/distros/__init__.py

@@ -169,6 +169,7 @@ def __init__(self, name, cfg, paths):
         self.package_managers: List[PackageManager] = []
         self._dhcp_client = None
         self._fallback_interface = None
+        self.is_linux = True
 
     def _unpickle(self, ci_pkl_version: int) -> None:
         """Perform deserialization fixes for Distro."""
@@ -185,6 +186,8 @@ def _unpickle(self, ci_pkl_version: int) -> None:
             self._dhcp_client = None
         if not hasattr(self, "_fallback_interface"):
             self._fallback_interface = None
+        if not hasattr(self, "is_linux"):
+            self.is_linux = True
 
     def _validate_entry(self, entry):
         if isinstance(entry, str):

cloudinit/distros/bsd.py

@@ -40,6 +40,13 @@ def __init__(self, name, cfg, paths):
         cfg["rsyslog_svcname"] = "rsyslogd"
         self.osfamily = platform.system().lower()
         self.net_ops = bsd_netops.BsdNetOps
+        self.is_linux = False
+
+    def _unpickle(self, ci_pkl_version: int) -> None:
+        super()._unpickle(ci_pkl_version)
+
+        # this needs to be after the super class _unpickle to override it
+        self.is_linux = False
 
     def _read_system_hostname(self):
         sys_hostname = self._read_hostname(self.hostname_conf_fn)

cloudinit/util.py

@@ -490,6 +490,12 @@ def multi_log(
 
 @lru_cache()
 def is_Linux():
+    """deprecated: prefer Distro object's `is_linux` property
+
+    Multiple sources of truth is bad, and already know whether we are
+    working with Linux from the Distro class. Using Distro offers greater code
+    reusablity, cleaner code, and easier maintenance.
+    """
     return "Linux" in platform.system()