mgr/cephadm: prepare schedule.py for per-service-type host filtering

Prepare schedule.py for per-service-type host filtering based on allowed
host addresses/networks. Add a new HostSelector protocol type to the
module defining what the filtering interface looks like.

This interface is intended allows CephService classes to "take over" the
network based filtering of nodes prior to placement and customize the
behavior of this step in cephamd's placement algorithm.

Note that the type must be passed in to the HostAssignment class as an
optional argument. If nothing is passed the class behaves as it did
before.

Signed-off-by: John Mulligan <jmulligan@redhat.com>

diff --git a/src/pybind/mgr/cephadm/schedule.py b/src/pybind/mgr/cephadm/schedule.py
index 13bb5efaccca3741bcc6960831d18bf590d51166..69aacf0a9cce0d86166d46e3ffbc8067ea27c5f8 100644 (file)
--- a/src/pybind/mgr/cephadm/schedule.py
+++ b/src/pybind/mgr/cephadm/schedule.py
@@ -2,7 +2,17 @@ import ipaddress
 import hashlib
 import logging
 import random
-from typing import List, Optional, Callable, TypeVar, Tuple, NamedTuple, Dict
+from typing import (
+    Callable,
+    Dict,
+    Iterable,
+    List,
+    NamedTuple,
+    Optional,
+    Protocol,
+    Tuple,
+    TypeVar,
+)
 
 import orchestrator
 from ceph.deployment.service_spec import ServiceSpec
@@ -143,6 +153,15 @@ class DaemonPlacement(NamedTuple):
         return rank_map[dd.rank][dd.rank_generation] == dd.daemon_id
 
 
+class HostSelector(Protocol):
+    def filter_host_candidates(
+        self,
+        spec: ServiceSpec,
+        candidates: Iterable[DaemonPlacement],
+    ) -> List[DaemonPlacement]:
+        "Filter candidates for host/ip matching."
+
+
 class HostAssignment(object):
 
     def __init__(self,
@@ -159,7 +178,8 @@ class HostAssignment(object):
                  per_host_daemon_type: Optional[str] = None,
                  rank_map: Optional[Dict[int, Dict[int, Optional[str]]]] = None,
                  blocking_daemon_hosts: Optional[List[orchestrator.HostSpec]] = None,
-                 upgrade_in_progress: bool = False
+                 upgrade_in_progress: bool = False,
+                 host_selector: Optional[HostSelector] = None,
                  ):
         assert spec
         self.spec = spec  # type: ServiceSpec
@@ -178,6 +198,7 @@ class HostAssignment(object):
         self.ports_start = spec.get_port_start()
         self.rank_map = rank_map
         self.upgrade_in_progress = upgrade_in_progress
+        self.host_selector = host_selector
 
     def hosts_by_label(self, label: str) -> List[orchestrator.HostSpec]:
         return [h for h in self.hosts if label in h.labels]
@@ -467,7 +488,9 @@ class HostAssignment(object):
                 "placement spec is empty: no hosts, no label, no pattern, no count")
 
         # allocate an IP?
-        if self.spec.networks or self.spec.ip_addrs:
+        if self.host_selector:
+            ls = self.host_selector.filter_host_candidates(self.spec, ls)
+        elif self.spec.networks or self.spec.ip_addrs:
             orig = ls.copy()
             ls = []
             for p in orig: