warn users to use natty
diff --git a/build_lxc.sh b/build_lxc.sh
index c019d7e..54ee375 100755
--- a/build_lxc.sh
+++ b/build_lxc.sh
@@ -12,6 +12,11 @@
 # Param string to pass to stack.sh.  Like "EC2_DMZ_HOST=192.168.1.1 MYSQL_USER=nova"
 STACKSH_PARAMS=${STACKSH_PARAMS:-}
 
+# Warn users who aren't on natty
+if ! grep -q natty /etc/lsb-release; then
+    echo "WARNING: this script has only been tested on natty"
+fi
+
 # Install deps
 apt-get install lxc debootstrap