have instances be filtered by ID in case of no filtering criteria passed in

and then switch from using order by ID as a fallback for all ordering and instead
just set instances ordering to ID as default to prevent
OrderedManyToMany fields ordering from being interrupted.

awx/api/filters.py

@@ -398,11 +398,11 @@ class OrderByBackend(BaseFilterBackend):
                         order_by = value.split(',')
                     else:
                         order_by = (value,)
-            if order_by is None:
-                order_by = self.get_default_ordering(view)
+            default_order_by = self.get_default_ordering(view)
+            # glue the order by and default order by together so that the default is the backup option
+            order_by = list(order_by or []) + list(default_order_by or [])
             if order_by:
                 order_by = self._validate_ordering_fields(queryset.model, order_by)
-
                 # Special handling of the type field for ordering. In this
                 # case, we're not sorting exactly on the type field, but
                 # given the limited number of views with multiple types,

awx/api/views/__init__.py

@@ -365,6 +365,7 @@ class InstanceList(ListAPIView):
     model = models.Instance
     serializer_class = serializers.InstanceSerializer
     search_fields = ('hostname',)
+    ordering = ('id',)
 
 
 class InstanceDetail(RetrieveUpdateAPIView):