diff --git a/cluster-mgmt/start-mininet.sh b/cluster-mgmt/start-mininet.sh
index 4fb8531..e226c39 100755
--- a/cluster-mgmt/start-mininet.sh
+++ b/cluster-mgmt/start-mininet.sh
@@ -5,13 +5,14 @@
 ZK_LIB='/var/lib/zookeeper'
 CASSANDRA_LIB='/var/lib/cassandra'
 
-if [ $# == 1 ]; then
-  basename=$1
-else
-  echo "$0 basename"
+if [ x$ONOS_CLUSTER_BASENAME == "x" -o x$ONOS_CLUSTER_NR_NODES == "x" ]; then
+  echo "set environment variable ONOS_CLUSTER_BASENAME and ONOS_CLUSTER_NR_NODES"
   exit
 fi
 
+basename=$ONOS_CLUSTER_BASENAME
+NR_NODES=$ONOS_CLUSTER_NR_NODES
+
 dsh -g $basename 'uname -a'
 
 dsh -g ${basename} 'cd ONOS/test-network/mininet; ./tunnel_onsdemo.sh start'