Add an option for enabling monitoring in gce/config-default.sh and disable it

for tests.
Updated heapster readme.

cluster/gce/config-default.sh

@@ -35,3 +35,5 @@ MINION_SCOPES="compute-rw"
 # Increase the sleep interval value if concerned about API rate limits. 3, in seconds, is the default.
 POLL_SLEEP_INTERVAL=3
 PORTAL_NET="10.0.0.0/16"
+# When set to true, heapster will be setup as part of the cluster bring up.
+MONITORING=true

cluster/gce/config-test.sh

@@ -35,3 +35,4 @@ MINION_SCOPES=""
 # Increase the sleep interval value if concerned about API rate limits. 3, in seconds, is the default.
 POLL_SLEEP_INTERVAL=3
 PORTAL_NET="10.0.0.0/16"
+MONITORING=false

cluster/gce/util.sh

@@ -575,10 +575,7 @@ function restart-kube-proxy {
 
 # Setup monitoring using heapster and InfluxDB
 function setup-monitoring {
-    read -p "Setup monitoring of the cluster using heapster (https://github.com/GoogleCloudPlatform/heapster) [Y|N]? " -n 1 -r
-    echo
-    if [[ $REPLY =~ ^[Yy]$ ]]
-    then
+    if [ $MONITORING ]; then
 	teardown-monitoring
 	kubectl.sh create -f "${KUBE_ROOT}/examples/monitoring/influx-grafana-pod.json" && 
 	kubectl.sh create -f "${KUBE_ROOT}/examples/monitoring/influx-grafana-service.json" &&