diff --git a/prometheus.go b/prometheus.go
index 7e131f3..bb00201 100644
--- a/prometheus.go
+++ b/prometheus.go
@@ -18,6 +18,7 @@ var (
 	metricRegistry        *prometheus.Registry   = nil
 	metricApiCounter      *prometheus.CounterVec = nil
 	metricApiSummary      *prometheus.SummaryVec = nil
+	instance              string                 = "--unknown--"
 )
 
 type metricExporterHandler struct {
@@ -41,7 +42,6 @@ func dumpMetricExporterPusher() error {
 }
 
 func InitMetrics(instanceValue string) {
-	var instance = instanceValue
 	if instanceValue == "" {
 		instance = getInstanceIpAddress()
 	} else if ap := strings.Split(instanceValue, ":"); len(ap) == 2 &&
@@ -52,18 +52,18 @@ func InitMetrics(instanceValue string) {
 
 	metricApiCounter = prometheus.NewCounterVec(
 		prometheus.CounterOpts{
-			Name:        "api_requests_total",
-			Help:        "How many HTTP requests processed",
-			ConstLabels: prometheus.Labels{"instance": instance},
+			Name: "api_requests_total",
+			Help: "How many HTTP requests processed",
+			//ConstLabels: prometheus.Labels{"instance": instance},
 		},
 		[]string{"api", "errcode", "appid"},
 	)
 	metricApiSummary = prometheus.NewSummaryVec(
 		prometheus.SummaryOpts{
-			Name:        "api_requests_summary",
-			Help:        "The api request summary of cost.",
-			Objectives:  map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
-			ConstLabels: prometheus.Labels{"instance": instance},
+			Name:       "api_requests_summary",
+			Help:       "The api request summary of cost.",
+			Objectives: map[float64]float64{0.5: 0.05, 0.9: 0.01, 0.99: 0.001},
+			//ConstLabels: prometheus.Labels{"instance": instance},
 		},
 		[]string{"api", "errcode", "appid"},
 	)
@@ -90,7 +90,11 @@ func SetupMetricsExporterPusher(pushgateway string, jobname string) {
 		jobname = fmt.Sprintf("api-metrics-job-%s", getExeFilename())
 	}
 
-	var pusher = push.New(pushgateway, jobname).Gatherer(metricRegistry)
+	var pusher = push.
+		New(pushgateway, jobname).
+		Grouping("instance", instance).
+		Gatherer(metricRegistry)
+
 	MetricExporterPusher = func() error {
 		RecordMetrics("push_metrics_to_prometheus", "0", "selfmonitoring", 1.0)
 		return pusher.Push()