Don't register metrics unless on leading master

cluster-autoscaler/main.go

@@ -233,6 +233,7 @@ func registerSignalHandlers(autoscaler core.Autoscaler) {
 }
 
 func run(healthCheck *metrics.HealthCheck) {
+	metrics.RegisterAll()
 	kubeClient := createKubeClient()
 	kubeEventRecorder := kube_util.CreateEventRecorder(kubeClient)
 	opts := createAutoscalerOptions()

cluster-autoscaler/metrics/metrics.go

@@ -212,7 +212,8 @@ var (
 	)
 )
 
-func init() {
+// RegisterAll registers all metrics.
+func RegisterAll() {
 	prometheus.MustRegister(clusterSafeToAutoscale)
 	prometheus.MustRegister(nodesCount)
 	prometheus.MustRegister(nodeGroupsCount)