Fix handling of Pool NS changes

Closes-Bug: #1500798

Change-Id: Ie697f35a523a63617ba386f0dcde63600ce5dac6

designate/central/service.py

@@ -558,13 +558,22 @@ class Service(service.RPCService, service.Service):
     def _add_ns(self, context, zone, ns_record):
         # Get NS recordset
         # If the zone doesn't have an NS recordset yet, create one
-        try:
-            ns_recordset = self.find_recordset(
-                context, criterion={'domain_id': zone['id'], 'type': "NS"})
+        recordsets = self.find_recordsets(
+            context, criterion={'domain_id': zone['id'], 'type': "NS"}
+        )
 
-        except exceptions.RecordSetNotFound:
+        managed = []
+        for rs in recordsets:
+            if [r for r in rs.records if r.managed]:
+                managed.append(rs)
+
+        if len(managed) == 0:
             self._create_ns(context, zone, [ns_record])
             return
+        elif len(managed) != 1:
+            raise exceptions.RecordSetNotFound("No valid recordset found")
+
+        ns_recordset = managed[0]
 
         # Add new record to recordset based on the new nameserver
         ns_recordset.records.append(

designate/tests/test_central/test_service.py

@@ -2571,6 +2571,54 @@ class CentralServiceTest(CentralTestCase):
         self.assertEqual(set([n.hostname for n in pool.ns_records]),
                          set([n.data for n in ns_recordset.records]))
 
+    def test_update_pool_add_ns_record_with_existing_ns_in_zone(self):
+        # Create a server pool and domain
+        pool = self.create_pool(fixture=0)
+        domain = self.create_domain(pool_id=pool.id)
+
+        records = [
+            objects.Record(data="ns-1.example.com."),
+            objects.Record(data="ns-2.example.com.")
+        ]
+        recordset = objects.RecordSet(
+            name="nsx.%s" % domain.name,
+            type="NS",
+            records=records
+        )
+
+        self.central_service.create_recordset(
+            self.admin_context, domain.id, recordset)
+
+        ns_record_count = len(pool.ns_records)
+        new_ns_record = objects.PoolNsRecord(
+            priority=10,
+            hostname='ns-new.example.org.')
+
+        # Update and save the pool
+        pool.ns_records.append(new_ns_record)
+        self.central_service.update_pool(self.admin_context, pool)
+
+        # Fetch the pool
+        pool = self.central_service.get_pool(self.admin_context, pool.id)
+
+        # Verify that the pool was updated correctly
+        self.assertEqual(ns_record_count + 1, len(pool.ns_records))
+        self.assertIn(new_ns_record.hostname,
+                      [n.hostname for n in pool.ns_records])
+
+        # Fetch the domains NS recordset
+        ns_recordsets = self.central_service.find_recordsets(
+            self.admin_context,
+            criterion={'domain_id': domain.id, 'type': "NS"})
+
+        # It should have 2
+        self.assertEqual(2, len(ns_recordsets))
+
+        # Verify that the doamins NS records ware updated correctly
+        managed = [i for i in ns_recordsets if i.managed][0]
+        self.assertEqual(set([n.hostname for n in pool.ns_records]),
+                         set([n.data for n in managed.records]))
+
     def test_update_pool_remove_ns_record(self):
         # Create a server pool and domain
         pool = self.create_pool(fixture=0)