Optimize rpc handling for allocate and deallocate

If we are in multi_host mode we can save an extra rpc call by
sending the message to the instance host the first time. This
will prevent nova-network from having to resend the message
to actually allocate the fixed ips.

Part of blueprint optimize-nova-network

DocImpact: before multi_host only affected the network create
commands, but now it can be used at run-time to optimize the
path for allocating and deallocating fixed_ips, so it is important
to set it if you are using multi_host networks.

Change-Id: Ide48e0adb2e1051e31965c9a8422b27c1a9c40b3

3 files changed, 37 insertions, 8 deletions

diff --git a/nova/network/manager.py b/nova/network/manager.py
index b182613e2..e53573a0e 100644
--- a/nova/network/manager.py
+++ b/nova/network/manager.py
@@ -104,9 +104,6 @@ network_opts = [
     cfg.IntOpt('vpn_start',
                default=1000,
                help='First Vpn port for private networks'),
-    cfg.BoolOpt('multi_host',
-                default=False,
-                help='Default value for multi_host in networks'),
     cfg.IntOpt('network_size',
                default=256,
                help='Number of addresses in each private subnet'),
diff --git a/nova/network/rpcapi.py b/nova/network/rpcapi.py
index a9056845d..5c11f956f 100644
--- a/nova/network/rpcapi.py
+++ b/nova/network/rpcapi.py
@@ -27,6 +27,10 @@ rpcapi_opts = [
     cfg.StrOpt('network_topic',
                default='network',
                help='the topic network nodes listen on'),
+    cfg.BoolOpt('multi_host',
+                default=False,
+                help='Default value for multi_host in networks. Also, if set, '
+                     'some rpc network calls will be sent directly to host.'),
 ]
 
 CONF = cfg.CONF
@@ -153,15 +157,24 @@ class NetworkAPI(rpc_proxy.RpcProxy):
     def allocate_for_instance(self, ctxt, instance_id, instance_uuid,
                               project_id, host, rxtx_factor, vpn,
                               requested_networks, macs=None):
+        if CONF.multi_host:
+            topic = rpc.queue_get_for(ctxt, self.topic, host)
+        else:
+            topic = None
         return self.call(ctxt, self.make_msg('allocate_for_instance',
                 instance_id=instance_id, instance_uuid=instance_uuid,
                 project_id=project_id, host=host, rxtx_factor=rxtx_factor,
                 vpn=vpn, requested_networks=requested_networks, macs=macs),
-                version='1.8')
+                topic=topic, version='1.8')
 
     def deallocate_for_instance(self, ctxt, instance_id, project_id, host):
+        if CONF.multi_host:
+            topic = rpc.queue_get_for(ctxt, self.topic, host)
+        else:
+            topic = None
         return self.call(ctxt, self.make_msg('deallocate_for_instance',
-                instance_id=instance_id, project_id=project_id, host=host))
+                instance_id=instance_id, project_id=project_id, host=host),
+                topic=topic)
 
     def add_fixed_ip_to_instance(self, ctxt, instance_id, host, network_id):
         return self.call(ctxt, self.make_msg('add_fixed_ip_to_instance',
diff --git a/nova/tests/network/test_rpcapi.py b/nova/tests/network/test_rpcapi.py
index 132d5a433..f3a032dfe 100644
--- a/nova/tests/network/test_rpcapi.py
+++ b/nova/tests/network/test_rpcapi.py
@@ -28,6 +28,10 @@ CONF = cfg.CONF
 
 
 class NetworkRpcAPITestCase(test.TestCase):
+    def setUp(self):
+        super(NetworkRpcAPITestCase, self).setUp()
+        self.flags(multi_host=True)
+
     def _test_network_api(self, method, rpc_method, **kwargs):
         ctxt = context.RequestContext('fake_user', 'fake_project')
         rpcapi = network_rpcapi.NetworkAPI()
@@ -45,13 +49,18 @@ class NetworkRpcAPITestCase(test.TestCase):
             '_rpc_allocate_fixed_ip', 'deallocate_fixed_ip', 'update_dns',
             '_associate_floating_ip', '_disassociate_floating_ip',
             'lease_fixed_ip', 'release_fixed_ip', 'migrate_instance_start',
-            'migrate_instance_finish', 'get_backdoor_port'
+            'migrate_instance_finish', 'get_backdoor_port',
+            'allocate_for_instance', 'deallocate_for_instance',
         ]
         if method in targeted_methods and 'host' in kwargs:
-            if method != 'deallocate_fixed_ip':
+            if method not in ['allocate_for_instance',
+                              'deallocate_for_instance',
+                              'deallocate_fixed_ip']:
                 del expected_msg['args']['host']
             host = kwargs['host']
-            expected_topic = rpc.queue_get_for(ctxt, CONF.network_topic, host)
+            if CONF.multi_host:
+                expected_topic = rpc.queue_get_for(ctxt, CONF.network_topic,
+                                                   host)
         expected_msg['version'] = expected_version
 
         self.fake_args = None
@@ -148,6 +157,16 @@ class NetworkRpcAPITestCase(test.TestCase):
         self._test_network_api('deallocate_floating_ip', rpc_method='call',
                 address='addr', affect_auto_assigned=True)
 
+    def test_allocate_floating_ip_no_multi(self):
+        self.flags(multi_host=False)
+        self._test_network_api('allocate_floating_ip', rpc_method='call',
+                project_id='fake_id', pool='fake_pool', auto_assigned=False)
+
+    def test_deallocate_floating_ip_no_multi(self):
+        self.flags(multi_host=False)
+        self._test_network_api('deallocate_floating_ip', rpc_method='call',
+                address='addr', affect_auto_assigned=True)
+
     def test_associate_floating_ip(self):
         self._test_network_api('associate_floating_ip', rpc_method='call',
                 floating_address='blah', fixed_address='foo',