diff --git a/lib/constants.py b/lib/constants.py
index cd6493d23c75f54c13d01bc5d3177845649f88ff..8febfdce96ff6e37bc199c4c18fae92403aaa5c4 100644
--- a/lib/constants.py
+++ b/lib/constants.py
@@ -315,6 +315,9 @@ BIND_ADDRESS_GLOBAL = "0.0.0.0"
 MIN_VG_SIZE = 20480
 DEFAULT_MAC_PREFIX = "aa:00:00"
 LVM_STRIPECOUNT = _autoconf.LVM_STRIPECOUNT
+# default maximum instance wait time, in seconds.
+DEFAULT_SHUTDOWN_TIMEOUT = 120
+
 
 # RPC constants
 (RPC_ENCODING_NONE,