Create default Vxlan and Vnet configs (#13409) (#15497)

* Create default Vxlan and Vnet configs for ToRs with Appliance Resource type

src/sonic-config-engine/minigraph.py

@@ -1255,6 +1255,28 @@ def parse_spine_chassis_fe(results, vni, lo_intfs, phyport_intfs, pc_intfs, pc_m
             # Enslave the port channel interface to a Vnet
             pc_intfs[pc_intf] = {'vnet_name': chassis_vnet}        
 
+def parse_default_vxlan_decap(results, vni, lo_intfs):
+    vnet ='Vnet-default'
+    vxlan_tunnel = 'tunnel_v4'
+
+    # Vxlan tunnel information
+    lo_addr = '0.0.0.0'
+    for lo in lo_intfs:
+        lo_network = ipaddress.ip_network(UNICODE_TYPE(lo[1]), False)
+        if lo_network.version == 4:
+            lo_addr = str(lo_network.network_address)
+            break
+    results['VXLAN_TUNNEL'] = {vxlan_tunnel: {
+        'src_ip': lo_addr
+    }}
+
+    # Vnet information
+    results['VNET'] = {vnet: {
+        'vxlan_tunnel': vxlan_tunnel,
+        'scope': "default",
+        'vni': vni
+    }}
+
 ###############################################################################
 #
 # Post-processing functions
@@ -1605,9 +1627,10 @@ def parse_xml(filename, platform=None, port_config_file=None, asic_name=None, hw
         for key in voq_inband_intfs:
            results['VOQ_INBAND_INTERFACE'][key] = voq_inband_intfs[key]
 
-
     if resource_type is not None:
         results['DEVICE_METADATA']['localhost']['resource_type'] = resource_type
+        if 'Appliance' in resource_type:
+            parse_default_vxlan_decap(results, vni_default, lo_intfs)
 
     if downstream_subrole is not None:
         results['DEVICE_METADATA']['localhost']['downstream_subrole'] = downstream_subrole

src/sonic-config-engine/tests/t0-sample-deployment-id.xml

@@ -731,6 +731,11 @@
             <a:Reference i:nil="true"/>
             <a:Value>2.2.2.2</a:Value>
           </a:DeviceProperty>
+          <a:DeviceProperty>
+            <a:Name>ResourceType</a:Name>
+            <a:Reference i:nil="true"/>
+            <a:Value>HaAppliance</a:Value>
+          </a:DeviceProperty>
         </a:Properties>
       </a:DeviceMetadata>
     </Devices>

src/sonic-config-engine/tests/test_cfggen.py

@@ -494,6 +494,22 @@ class TestCfgGen(TestCase):
             utils.to_dict("{'lanes': '101,102,103,104', 'fec': 'rs', 'pfc_asym': 'off', 'mtu': '9100', 'tpid': '0x8100', 'alias': 'fortyGigE0/124', 'admin_status': 'up', 'speed': '100000', 'description': 'ARISTA04T1:Ethernet1/1'}")
         )
 
+    def test_minigraph_default_vxlan(self):
+        argument = '-m "' + self.sample_graph_deployment_id + '" -p "' + self.port_config + '" -v "VXLAN_TUNNEL"'
+        output = self.run_script(argument)
+        self.assertEqual(
+            utils.to_dict(output.strip()),
+            utils.to_dict("{'tunnel_v4': {'src_ip': '10.1.0.32'}}")
+        )
+
+    def test_minigraph_default_vnet(self):
+        argument = '-m "' + self.sample_graph_deployment_id + '" -p "' + self.port_config + '" -v "VNET"'
+        output = self.run_script(argument)
+        self.assertEqual(
+            utils.to_dict(output.strip()),
+            utils.to_dict("{'Vnet-default': {'vxlan_tunnel': 'tunnel_v4', 'scope': 'default', 'vni': 8000}}")
+        )
+
     def test_minigraph_bgp(self):
         argument = '-m "' + self.sample_graph_bgp_speaker + '" -p "' + self.port_config + '" -v "BGP_NEIGHBOR[\'10.0.0.59\']"'
         output = self.run_script(argument)