Serialize mtu for dpdk interface with 'i40e' driver

On NIC: XL710 with driver 'i40e'  MTU does not take into
account 4 bytes VLAN tag, so we should increase it manually

DocImpact
Change-Id: I3d95db9ec6fae4d8cd397c429d785dbdf1502b21
Partial-Bug: #1587310
Co-Authored-By: Fedor Zhadaev <fzhadaev@mirantis.com>
(cherry picked from commit 737556d)

nailgun/nailgun/consts.py

@@ -531,3 +531,7 @@ HYPERVISORS = Enum(
 )
 
 DPDK_DRIVER_IN_SRIOV_CASE = 'vfio-pci'
+
+DEFAULT_MTU = 1500
+
+SIZE_OF_VLAN_TAG = 4

nailgun/nailgun/network/neutron.py

@@ -32,6 +32,7 @@ from nailgun.network.manager import AssignIPs70Mixin
 from nailgun.network.manager import AssignIPsLegacyMixin
 from nailgun.network.manager import NetworkManager
 from nailgun import objects
+from nailgun import utils
 
 from nailgun.orchestrator.neutron_serializers import \
     NeutronNetworkTemplateSerializer70
@@ -553,4 +554,28 @@ class NeutronManager70(
 
 
 class NeutronManager80(AllocateVIPs80Mixin, NeutronManager70):
-    pass
+    @classmethod
+    def get_iface_properties(cls, iface):
+        result = super(NeutronManager80, cls).get_iface_properties(iface)
+
+        if (iface.type == consts.NETWORK_INTERFACE_TYPES.ether and
+                iface.driver == 'i40e' and
+                objects.NIC.dpdk_enabled(iface)):
+            # On NIC with i40e driver MTU should be increased manually
+            # because driver automatically sets value 4 less
+            # LP 1587310
+            mtu = utils.get_in(result, 'mtu', 'value', 'value')
+            if mtu:
+                result.update({
+                    'mtu': {
+                        'value': {
+                            'value': mtu + consts.SIZE_OF_VLAN_TAG}
+                    }})
+            else:
+                result.update({
+                    'mtu': {
+                        'value': {
+                            'value':
+                                consts.DEFAULT_MTU + consts.SIZE_OF_VLAN_TAG}
+                    }})
+        return result

nailgun/nailgun/test/integration/test_orchestrator_serializer_90.py

@@ -136,7 +136,7 @@ class TestDeploymentAttributesSerialization90(
     @mock.patch('nailgun.objects.Release.get_supported_dpdk_drivers')
     def _check_dpdk_serializing(self, drivers_mock, has_vlan_tag=False,
                                 sriov=False, max_queues=0,
-                                dpdk_cpu_pinning=0):
+                                dpdk_cpu_pinning=0, nic_driver=None):
         drivers_mock.return_value = {
             'driver_1': ['test_id:1', 'test_id:2']
         }
@@ -159,6 +159,8 @@ class TestDeploymentAttributesSerialization90(
         dpdk_nic.meta['max_queues'] = max_queues
         if dpdk_cpu_pinning:
             node.attributes['cpu_pinning']['dpdk']['value'] = dpdk_cpu_pinning
+        if nic_driver:
+            dpdk_nic.driver = nic_driver
 
         objects.Cluster.prepare_for_deployment(self.cluster_db)
 
@@ -207,6 +209,9 @@ class TestDeploymentAttributesSerialization90(
                              min(max_queues, dpdk_cpu_pinning - 1))
         else:
             self.assertFalse('max_queues' in vendor_specific)
+        if nic_driver:
+            self.assertEqual(dpdk_interface['mtu']['value']['value'],
+                             consts.DEFAULT_MTU + consts.SIZE_OF_VLAN_TAG)
 
     def test_serialization_with_dpdk(self):
         self._check_dpdk_serializing()
@@ -222,6 +227,12 @@ class TestDeploymentAttributesSerialization90(
         self._create_cluster_with_vxlan()
         self._check_dpdk_serializing(has_vlan_tag=True)
 
+    def test_serialization_with_dpdk_with_i40e_driver(self):
+        driver = 'i40e'
+        dpdk_cpu_pinning = 4
+        self._check_dpdk_serializing(nic_driver=driver,
+                                     dpdk_cpu_pinning=dpdk_cpu_pinning)
+
     def test_serialization_with_dpdk_queues_limited_max_queues(self):
         max_queues = 2
         dpdk_cpu_pinning = 4