mgr/cephadm: extend stray service detection with a general ignore hook

Extend the system's current stray service detection with a new method on
the service classes so that new classes can hook into the stray services
in the case that ceph services and cephadm services have differing names
or use subsystems that call into ceph with different names (my use
case).

Signed-off-by: John Mulligan <[email protected]>

Author: phlogistonjohn

src/pybind/mgr/cephadm/serve.py

@@ -482,7 +482,9 @@ def _check_for_strays(self) -> None:
         if self.mgr.warn_on_stray_hosts or self.mgr.warn_on_stray_daemons:
             ls = self.mgr.list_servers()
             self.log.debug(ls)
-            managed = self.mgr.cache.get_daemon_names()
+            managed_daemons = self.mgr.cache.get_daemons()
+            stray_filter = self._build_stray_filter(managed_daemons)
+            managed = [d.name() for d in managed_daemons]
             host_detail = []     # type: List[str]
             host_num_daemons = 0
             daemon_detail = []  # type: List[str]
@@ -496,11 +498,7 @@ def _check_for_strays(self) -> None:
                     daemon_id = s.get('id')
                     assert daemon_id
                     name = self._service_reference_name(s.get('type'), daemon_id)
-                    if s.get('type') == 'tcmu-runner':
-                        # because we don't track tcmu-runner daemons in the host cache
-                        # and don't have a way to check if the daemon is part of iscsi service
-                        # we assume that all tcmu-runner daemons are managed by cephadm
-                        managed.append(name)
+                    managed.extend(stray_filter(s.get('type'), daemon_id, name))
                     # Don't mark daemons we just created/removed in the last minute as stray.
                     # It may take some time for the mgr to become aware the daemon
                     # had been created/removed.
@@ -544,6 +542,31 @@ def _service_reference_name(self, service_type: str, daemon_id: str) -> str:
             )
         return name
 
+    def _build_stray_filter(
+        self, managed: List[orchestrator.DaemonDescription]
+    ) -> Callable[[str, str, str], List[str]]:
+        svcs = {
+            daemon_type_to_service(cast(str, dd.daemon_type))
+            for dd in managed
+        }
+        _services = [self.mgr.cephadm_services[dt] for dt in svcs]
+
+        def _filter(
+            service_type: str, daemon_id: str, name: str
+        ) -> List[str]:
+            if service_type == 'tcmu-runner':
+                # because we don't track tcmu-runner daemons in the host cache
+                # and don't have a way to check if the daemon is part of iscsi service
+                # we assume that all tcmu-runner daemons are managed by cephadm
+                return [name]
+            out = []
+            for svc in _services:
+                if svc.ignore_possible_stray(service_type, daemon_id, name):
+                    out.append(name)
+            return out
+
+        return _filter
+
     def _check_for_moved_osds(self) -> None:
         self.log.debug('_check_for_moved_osds')
         all_osds: DefaultDict[int, List[orchestrator.DaemonDescription]] = defaultdict(list)

src/pybind/mgr/cephadm/services/cephadmservice.py

@@ -564,6 +564,16 @@ def purge(self, service_name: str) -> None:
         """Called to carry out any purge tasks following service removal"""
         logger.debug(f'Purge called for {self.TYPE} - no action taken')
 
+    def ignore_possible_stray(
+        self, service_type: str, daemon_id: str, name: str
+    ) -> bool:
+        """Called to decide if a possible stray service should be ignored
+        because it "virtually" belongs to a service.
+        This is mainly needed when properly managed services spawn layered ceph
+        services with different names (for example).
+        """
+        return False
+
 
 class CephService(CephadmService):
     def generate_config(self, daemon_spec: CephadmDaemonDeploySpec) -> Tuple[Dict[str, Any], List[str]]: