diff --git a/lib/constants.py b/lib/constants.py
index 2a19b63bdef8a43d5d38d1ab83e3b56001264442..b2bd5650c2943b69e1b4c1ce4d054beff0d26cdb 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -141,6 +141,8 @@ XEN_INITRD = _autoconf.XEN_INITRD
 KVM_PATH = _autoconf.KVM_PATH
 
 VALUE_DEFAULT = "default"
+VALUE_AUTO = "auto"
+VALUE_GENERATE = "generate"
 VALUE_NONE = "none"
 
 # hooks-related constants