Always pass device_owner to _ipam_get_subnets()

There was one code path where the existing device_owner
value, which is used for subnet selection when service_type's
are in use was not passed to _imap_get_subnets().  This could
trigger one of two exceptions - HostNotCompatibleWithFixedIps()
or IpAddressGenerationFailureNoMatchingSubnet() depending
on the environment.  Pass it along if known.

Also update the IpAddressGenerationFailureNoMatchingSubnet
exception to print the network_id and service_type values since
it could aid in debugging the problem quicker.

Change-Id: Ic13901b92cac05e8ddf1092b66aa5bcc5623fa8a
Closes-bug: #1637366
(cherry picked from commit 0d4889df41)

neutron/db/ipam_backend_mixin.py

@@ -692,7 +692,8 @@ class IpamBackendMixin(db_base_plugin_common.DbBasePluginCommon):
             # subnets. Happens on routed networks when host isn't known.
             raise ipam_exceptions.DeferIpam()
 
-        raise ipam_exceptions.IpAddressGenerationFailureNoMatchingSubnet()
+        raise ipam_exceptions.IpAddressGenerationFailureNoMatchingSubnet(
+            network_id=network_id, service_type=service_type)
 
     def _find_candidate_subnets(self, context, network_id, host, service_type,
                                 fixed_configured):
@@ -773,7 +774,8 @@ class IpamBackendMixin(db_base_plugin_common.DbBasePluginCommon):
             new_host_requested = host and host != old_host
             if old_ips and new_host_requested and not fixed_ips_requested:
                 valid_subnets = self._ipam_get_subnets(
-                    context, old_port['network_id'], host)
+                    context, old_port['network_id'], host,
+                    service_type=old_port.get('device_owner'))
                 valid_subnet_ids = {s['id'] for s in valid_subnets}
                 for fixed_ip in old_ips:
                     if fixed_ip['subnet_id'] not in valid_subnet_ids:

neutron/ipam/exceptions.py

@@ -69,7 +69,8 @@ class IpAddressGenerationFailureAllSubnets(IpAddressGenerationFailure):
 
 
 class IpAddressGenerationFailureNoMatchingSubnet(IpAddressGenerationFailure):
-    message = _("No valid service subnet for the given device owner.")
+    message = _("No valid service subnet for the given device owner, "
+                "network %(network_id)s, service type %(service_type)s.")
 
 
 class IPAllocationFailed(exceptions.NeutronException):

neutron/tests/unit/extensions/test_subnet_service_types.py

@@ -12,6 +12,8 @@
 
 import webob.exc
 
+from neutron_lib.api.definitions import portbindings
+
 from neutron.db import db_base_plugin_v2
 from neutron.db import subnet_service_type_db_models
 from neutron.extensions import subnet_service_types
@@ -40,7 +42,7 @@ class SubnetServiceTypesExtensionTestPlugin(
     """Test plugin to mixin the subnet service_types extension.
     """
 
-    supported_extension_aliases = ["subnet-service-types"]
+    supported_extension_aliases = ["subnet-service-types", "binding"]
 
 
 class SubnetServiceTypesExtensionTestCase(
@@ -324,6 +326,29 @@ class SubnetServiceTypesExtensionTestCase(
         # applied
         port = self._update('ports', port['id'], data)
 
+    def test_update_port_host_binding(self):
+        with self.network() as network:
+            pass
+        service_type = 'compute:foo'
+        # Create a subnet with a service_type
+        self._create_service_subnet([service_type],
+                                    cidr=self.CIDRS[1],
+                                    network=network)
+        # Create a port with a matching device owner
+        network = network['network']
+        port = self._create_port(self.fmt,
+                                 net_id=network['id'],
+                                 tenant_id=network['tenant_id'],
+                                 device_owner=service_type,
+                                 arg_list=(portbindings.HOST_ID,),
+                                 **{portbindings.HOST_ID: 'fakehost'})
+        port = self.deserialize('json', port)['port']
+        # Update the port's host binding.
+        data = {'port': {portbindings.HOST_ID: 'fakehost2'}}
+        # self._update will fail with a MismatchError if the update cannot be
+        # applied
+        port = self._update('ports', port['id'], data)
+
 
 class SubnetServiceTypesExtensionTestCasev6(
         SubnetServiceTypesExtensionTestCase):