Update VTN config generation to use VTN Service
diff --git a/xos/synchronizers/onos/steps/sync_onosapp.py b/xos/synchronizers/onos/steps/sync_onosapp.py
index add749d..1233ad7 100644
--- a/xos/synchronizers/onos/steps/sync_onosapp.py
+++ b/xos/synchronizers/onos/steps/sync_onosapp.py
@@ -17,6 +17,7 @@
 from services.onos.models import ONOSService, ONOSApp
 from xos.logger import Logger, logging
 from services.vrouter.models import VRouterService
+from services.vtn.models import VTNService
 
 # hpclibrary will be in steps/..
 parentdir = os.path.join(os.path.dirname(__file__),"..")
@@ -145,16 +146,25 @@
     # This function currently assumes a single Deployment and Site
     def get_vtn_config(self, o, attrs):
 
-        # The "attrs" argument contains a list of all service and tenant attributes
-        # If an attribute is present, use it in the configuration
-        # Otherwise save the attriute with a reasonable (for a CORD devel pod) default value
-        # The admin will see all possible configuration values and the assigned defaults
-        privateGatewayMac = self.attribute_default(o, attrs, "privateGatewayMac", "00:00:00:00:00:01")
-        localManagementIp = self.attribute_default(o, attrs, "localManagementIp", "172.27.0.1/24")
-        ovsdbPort = self.attribute_default(o, attrs, "ovsdbPort", "6641")
-        sshPort = self.attribute_default(o, attrs, "sshPort", "22")
-        sshUser = self.attribute_default(o, attrs, "sshUser", "root")
-        sshKeyFile = self.attribute_default(o, attrs, "sshKeyFile", "/root/node_key")
+        privateGatewayMac = None
+        localManagementIp = None
+        ovsdbPort = None
+        sshPort = None
+        sshUser = None
+        sshKeyFile = None
+        mgmtSubnetBits = None
+
+        # VTN-specific configuration from the VTN Service
+        vtns = VTNService.get_service_objects().all()
+        if vtns:
+            vtn = vtns[0]
+            privateGatewayMac = vtn.privateGatewayMac
+            localManagementIp = vtn.localManagementIp
+            ovsdbPort = vtn.ovsdbPort
+            sshPort = vtn.sshPort
+            sshUser = vtn.sshUser
+            sshKeyFile = vtn.sshKeyFile
+            mgmtSubnetBits = vtn.mgmtSubnetBits
 
         # OpenStack endpoints and credentials
         keystone_server = "http://keystone:5000/v2.0/"
@@ -194,11 +204,6 @@
         }
 
         # Generate apps->org.onosproject.cordvtn->cordvtn->nodes
-
-        # We need to generate a CIDR address for the physical node's
-        # address on the management network
-        mgmtSubnetBits = self.attribute_default(o, attrs, "mgmtSubnetBits", "24")
-
         nodes = Node.objects.all()
         for node in nodes:
             nodeip = socket.gethostbyname(node.name)