diff --git a/docs/gitbook/how-it-works.md b/docs/gitbook/how-it-works.md
index 0a07d68b..03378a7a 100644
--- a/docs/gitbook/how-it-works.md
+++ b/docs/gitbook/how-it-works.md
@@ -33,6 +33,8 @@ spec:
   service:
     # container port
     port: 9898
+    # service port name (optional, will default to "http")
+    portName: http-podinfo
     # Istio gateways (optional)
     gateways:
     - public-gateway.istio-system.svc.cluster.local
@@ -115,6 +117,8 @@ spec:
   service:
     # container port
     port: 9898
+    # service port name (optional, will default to "http")
+    portName: http-frontend
     # Istio gateways (optional)
     gateways:
     - public-gateway.istio-system.svc.cluster.local
@@ -484,6 +488,37 @@ The above configuration validates the canary by checking
 if the HTTP 404 req/sec percentage is below 5 percent of the total traffic.
 If the 404s rate reaches the 5% threshold, then the canary fails.
 
+```yaml
+  canaryAnalysis:
+    threshold: 1
+    maxWeight: 50
+    stepWeight: 5
+    metrics:
+    - name: "rpc error rate"
+      threshold: 5
+      query: |
+        100 - (sum
+            rate(
+                grpc_server_handled_total{
+                  grpc_service="my.TestService",
+                  grpc_code!="OK"
+                }[1m]
+            )
+        )
+        /
+        sum(
+            rate(
+                grpc_server_started_total{
+                  grpc_service="my.TestService"
+                }[1m]
+            )
+        ) * 100
+```
+
+The above configuration validates the canary by checking if the percentage of
+non-OK GRPC req/sec is below 5 percent of the total requests. If the non-OK
+rate reaches the 5% threshold, then the canary fails.
+
 When specifying a query, Flagger will run the promql query and convert the result to float64. 
 Then it compares the query result value with the metric threshold value.
 
diff --git a/pkg/apis/flagger/v1alpha3/types.go b/pkg/apis/flagger/v1alpha3/types.go
index d0650524..92bc5516 100755
--- a/pkg/apis/flagger/v1alpha3/types.go
+++ b/pkg/apis/flagger/v1alpha3/types.go
@@ -17,10 +17,11 @@ limitations under the License.
 package v1alpha3
 
 import (
+	"time"
+
 	istiov1alpha3 "github.com/weaveworks/flagger/pkg/apis/istio/v1alpha3"
 	hpav1 "k8s.io/api/autoscaling/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
-	"time"
 )
 
 const (
@@ -111,6 +112,7 @@ type CanaryStatus struct {
 // and Istio Virtual Service
 type CanaryService struct {
 	Port       int32                            `json:"port"`
+	PortName   string                           `json:"portName,omitempty"`
 	Match      []istiov1alpha3.HTTPMatchRequest `json:"match,omitempty"`
 	Rewrite    *istiov1alpha3.HTTPRewrite       `json:"rewrite,omitempty"`
 	Timeout    string                           `json:"timeout,omitempty"`
diff --git a/pkg/router/kubernetes.go b/pkg/router/kubernetes.go
index f42819d6..f0158513 100644
--- a/pkg/router/kubernetes.go
+++ b/pkg/router/kubernetes.go
@@ -2,6 +2,7 @@ package router
 
 import (
 	"fmt"
+
 	flaggerv1 "github.com/weaveworks/flagger/pkg/apis/flagger/v1alpha3"
 	clientset "github.com/weaveworks/flagger/pkg/client/clientset/versioned"
 	"go.uber.org/zap"
@@ -24,6 +25,11 @@ type KubernetesRouter struct {
 func (c *KubernetesRouter) Sync(cd *flaggerv1.Canary) error {
 	targetName := cd.Spec.TargetRef.Name
 	primaryName := fmt.Sprintf("%s-primary", targetName)
+	portName := cd.Spec.Service.PortName
+	if portName == "" {
+		portName = "http"
+	}
+
 	canaryService, err := c.kubeClient.CoreV1().Services(cd.Namespace).Get(targetName, metav1.GetOptions{})
 	if errors.IsNotFound(err) {
 		canaryService = &corev1.Service{
@@ -43,7 +49,7 @@ func (c *KubernetesRouter) Sync(cd *flaggerv1.Canary) error {
 				Selector: map[string]string{"app": primaryName},
 				Ports: []corev1.ServicePort{
 					{
-						Name:     "http",
+						Name:     portName,
 						Protocol: corev1.ProtocolTCP,
 						Port:     cd.Spec.Service.Port,
 						TargetPort: intstr.IntOrString{
@@ -82,7 +88,7 @@ func (c *KubernetesRouter) Sync(cd *flaggerv1.Canary) error {
 				Selector: map[string]string{"app": targetName},
 				Ports: []corev1.ServicePort{
 					{
-						Name:     "http",
+						Name:     portName,
 						Protocol: corev1.ProtocolTCP,
 						Port:     cd.Spec.Service.Port,
 						TargetPort: intstr.IntOrString{
@@ -120,7 +126,7 @@ func (c *KubernetesRouter) Sync(cd *flaggerv1.Canary) error {
 				Selector: map[string]string{"app": primaryName},
 				Ports: []corev1.ServicePort{
 					{
-						Name:     "http",
+						Name:     portName,
 						Protocol: corev1.ProtocolTCP,
 						Port:     cd.Spec.Service.Port,
 						TargetPort: intstr.IntOrString{