diff --git a/functions b/functions
index 7fd37c0..75c20d7 100644
--- a/functions
+++ b/functions
@@ -115,6 +115,28 @@
 }
 
 
+# is_service_enabled() checks if the service(s) specified as arguments are
+# enabled by the user in **ENABLED_SERVICES**.
+#
+# If there are multiple services specified as arguments the test performs a
+# boolean OR or if any of the services specified on the command line
+# return true.
+#
+# There is a special cases for some 'catch-all' services::
+#   **nova** returns true if any service enabled start with **n-**
+#   **glance** returns true if any service enabled start with **g-**
+#   **quantum** returns true if any service enabled start with **q-**
+function is_service_enabled() {
+    services=$@
+    for service in ${services}; do
+        [[ ,${ENABLED_SERVICES}, =~ ,${service}, ]] && return 0
+        [[ ${service} == "nova" && ${ENABLED_SERVICES} =~ "n-" ]] && return 0
+        [[ ${service} == "glance" && ${ENABLED_SERVICES} =~ "g-" ]] && return 0
+        [[ ${service} == "quantum" && ${ENABLED_SERVICES} =~ "q-" ]] && return 0
+    done
+    return 1
+}
+
 
 # Test if the named environment variable is set and not zero length
 # is_set env-var
@@ -151,4 +173,4 @@
 }
 
 # Restore xtrace
-$XTRACE
\ No newline at end of file
+$XTRACE