diff --git a/lib/nova b/lib/nova
index d5fe7ac48e..5db2f8fcd3 100644
--- a/lib/nova
+++ b/lib/nova
@@ -45,6 +45,12 @@ NOVA_FAKE_CONF=$NOVA_CONF_DIR/nova-fake.conf
 NOVA_CELLS_DB=${NOVA_CELLS_DB:-nova_cell}
 
 NOVA_API_PASTE_INI=${NOVA_API_PASTE_INI:-$NOVA_CONF_DIR/api-paste.ini}
+# NOVA_API_VERSIONS valid options
+#   - default - setup API end points as nova does out of the box
+#   - v21default - make v21 the default on /v2
+# NOTE(sdague): this is for transitional testing of the Nova v21 API.
+# Expect to remove in L or M.
+NOVA_API_VERSIONS=${NOVA_API_VERSIONS:-default}
 
 if is_ssl_enabled_service "nova" || is_service_enabled tls-proxy; then
     NOVA_SERVICE_PROTOCOL="https"
@@ -263,6 +269,11 @@ function configure_nova {
 
         # Get the sample configuration file in place
         cp $NOVA_DIR/etc/nova/api-paste.ini $NOVA_CONF_DIR
+
+        # For testing v21 is equivalent to v2
+        if [[ "$NOVA_API_VERSION" == "v21default" ]]; then
+            sed -i s/": openstack_compute_api_v2$"/": openstack_compute_api_v21"/ "$NOVA_API_PASTE_INI"
+        fi
     fi
 
     if is_service_enabled n-cpu; then