python-shade expose MTU setting.

The networking API v2 specification, which is implemented by
openstack neutron, features an optional MTU parameter - when
creating a network, this allows operators to specify the value
for the maximum transmission unit value.

Change-Id: I288f02551555fff3e8b350fc6d7c6ae8f60c405c

releasenotes/notes/mtu-settings-8ce8b54d096580a2.yaml

@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    create_network now exposes the mtu api option in accordance to network
+    v2 api. This allows the operator to adjust the given MTU value which
+    is needed in various complex network deployments.

shade/openstackcloud.py

@@ -3462,7 +3462,8 @@ class OpenStackCloud(
     def create_network(self, name, shared=False, admin_state_up=True,
                        external=False, provider=None, project_id=None,
                        availability_zone_hints=None,
-                       port_security_enabled=None):
+                       port_security_enabled=None,
+                       mtu_size=None):
         """Create a network.
 
         :param string name: Name of the network being created.
@@ -3476,6 +3477,8 @@ class OpenStackCloud(
             will be created on (admin-only).
         :param list availability_zone_hints: A list of availability zone hints.
         :param bool port_security_enabled: Enable / Disable port security
+        :param int mtu_size: maximum transmission unit value to address
+            fragmentation. Minimum value is 68 for IPv4, and 1280 for IPv6.
 
         :returns: The network object.
         :raises: OpenStackCloudException on operation error.
@@ -3524,6 +3527,16 @@ class OpenStackCloud(
                     "Parameter 'port_security_enabled' must be a bool")
             network['port_security_enabled'] = port_security_enabled
 
+        if mtu_size:
+            if not isinstance(mtu_size, int):
+                raise exc.OpenStackCloudException(
+                    "Parameter 'mtu_size' must be an integer.")
+            if not mtu_size >= 68:
+                raise exc.OpenStackCloudException(
+                    "Parameter 'mtu_size' must be greater than 67.")
+
+            network['mtu'] = mtu_size
+
         data = self._network_client.post("/networks.json",
                                          json={'network': network})
 
@@ -11333,6 +11346,7 @@ class OpenStackCloud(
 
         :returns: Munch object with the usage
         """
+
         def parse_date(date):
             try:
                 return iso8601.parse_date(date)

shade/tests/unit/test_network.py

@@ -250,6 +250,41 @@ class TestNetwork(base.RequestsMockTestCase):
         self.assertEqual(mock_new_network_rep, network)
         self.assert_calls()
 
+    def test_create_network_with_mtu(self):
+        mtu_size = 1500
+        mock_new_network_rep = copy.copy(self.mock_new_network_rep)
+        mock_new_network_rep['mtu'] = mtu_size
+        self.register_uris([
+            dict(method='POST',
+                 uri=self.get_mock_url(
+                     'network', 'public', append=['v2.0', 'networks.json']),
+                 json={'network': mock_new_network_rep},
+                 validate=dict(
+                     json={'network': {
+                         'admin_state_up': True,
+                         'name': 'netname',
+                         'mtu': mtu_size}}))
+        ])
+        network = self.cloud.create_network("netname",
+                                            mtu_size=mtu_size
+                                            )
+        self.assertEqual(mock_new_network_rep, network)
+        self.assert_calls()
+
+    def test_create_network_with_wrong_mtu_size(self):
+        with testtools.ExpectedException(
+                shade.OpenStackCloudException,
+                "Parameter 'mtu_size' must be greater than 67."
+        ):
+            self.cloud.create_network("netname", mtu_size=42)
+
+    def test_create_network_with_wrong_mtu_type(self):
+        with testtools.ExpectedException(
+                shade.OpenStackCloudException,
+                "Parameter 'mtu_size' must be an integer."
+        ):
+            self.cloud.create_network("netname", mtu_size="fourty_two")
+
     def test_delete_network(self):
         network_id = "test-net-id"
         network_name = "network"