Do not bind VM ports directly

The hypervisor agent is hopefully named as the host it is running on,
and we still want to bind the native vlan for ironic directly,
but we do not want the VMs VLAN running on the host natively for
the host.

networking_ccloud/ml2/mech_driver.py

@@ -122,6 +122,23 @@ def get_workers(self):
         """
         return [service.RpcWorker([self], worker_process_count=0)]
 
+    def _should_bind_directly(self, context, hg_config):
+        # No direct binding here
+        if not hg_config.direct_binding:
+            return False
+
+        # Now we likely want a direct binding, unless the binding request
+        # comes for a VM on the given host
+        port = context.current
+        # We only want to override it for compute
+        device_owner = port.get('device_owner', None)
+        if not device_owner or not device_owner.startswith(
+            nl_const.DEVICE_OWNER_COMPUTE_PREFIX):
+            return
+
+        # So, it is for nova. We only do direct bindings for ironic.
+        return port.get(pb_api.VNIC_TYPE) == pb_api.VNIC_BAREMETAL
+
     def bind_port(self, context):
         """Attempt to bind a port.
 
@@ -187,7 +204,7 @@ def bind_port(self, context):
         if not context.binding_levels:
             # Port has not been bound to any segment --> top level binding --> hpb
             self._bind_port_hierarchical(context, binding_host, hg_config)
-        elif hg_config.direct_binding:
+        elif self._should_bind_directly(context, hg_config):
             self._bind_port_direct(context, binding_host, hg_config)
 
     def _bind_port_hierarchical(self, context, binding_host, hg_config):
@@ -213,7 +230,7 @@ def _bind_port_hierarchical(self, context, binding_host, hg_config):
         next_segment = context.allocate_dynamic_segment(segment_spec)
 
         # config update (direct bindings are handled in the next step)
-        if not hg_config.direct_binding:
+        if not self._should_bind_directly(context, hg_config):
             # send rpc call to agent
             net_external = context.network.current[extnet_api.EXTERNAL]
             self.handle_binding_host_changed(context._plugin_context, context.current['network_id'],