mirror.md

title	weight	toc	type	product	docs
Configure Request Mirroring	700	true	how-to	NGF	DOCS-000

Learn how to mirror your HTTP or gRPC traffic using NGINX Gateway Fabric.

---

Overview

HTTPRoute and GRPCRoute filters can be used to configure request mirroring. Mirroring copies a request to another backend.

In this guide, we will set up two applications, coffee and tea, and mirror requests between them. All requests sent to the coffee application will also be sent to the tea application automatically.

---

Before you begin

• [Install]({{< ref "/ngf/installation/" >}}) NGINX Gateway Fabric.

• Save the public IP address and port of NGINX Gateway Fabric into shell variables:

  GW_IP=XXX.YYY.ZZZ.III
  GW_PORT=<port number>
  

{{< note >}}In a production environment, you should have a DNS record for the external IP address that is exposed, and it should refer to the hostname that the gateway will forward for.{{< /note >}}

---

Set up

Create the coffee and tea applications in Kubernetes by copying and pasting the following block into your terminal:

kubectl apply -f - <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
  name: coffee
spec:
  replicas: 1
  selector:
    matchLabels:
      app: coffee
  template:
    metadata:
      labels:
        app: coffee
    spec:
      containers:
      - name: coffee
        image: nginxdemos/nginx-hello:plain-text
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: coffee
spec:
  ports:
  - port: 80
    targetPort: 8080
    protocol: TCP
    name: http
  selector:
    app: coffee
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: tea
spec:
  replicas: 1
  selector:
    matchLabels:
      app: tea
  template:
    metadata:
      labels:
        app: tea
    spec:
      containers:
      - name: tea
        image: nginxdemos/nginx-hello:plain-text
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: tea
spec:
  ports:
  - port: 80
    targetPort: 8080
    protocol: TCP
    name: http
  selector:
    app: tea
EOF

Run the following command to verify the resources were created:

kubectl get pods,svc

Your output should include the pods and services for coffee and tea:

NAME                          READY   STATUS              RESTARTS   AGE
pod/coffee-676c9f8944-dxvkt   0/1     ContainerCreating   0          3s
pod/tea-6fbfdcb95d-xl22n      0/1     ContainerCreating   0          3s

NAME                 TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
service/coffee       ClusterIP   10.96.151.184   <none>        80/TCP    3s
service/tea          ClusterIP   10.96.185.235   <none>        80/TCP    3s

---

Configure request mirroring

First, create the cafe Gateway resource:

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: cafe
spec:
  gatewayClassName: nginx
  listeners:
  - name: http
    port: 80
    protocol: HTTP
EOF

Now create an HTTPRoute that defines a RequestMirror filter that copies all requests sent to /coffee to be sent to the coffee backend and mirrored to the tea backend. Use the following command:

kubectl apply -f - <<EOF
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: mirror
spec:
  parentRefs:
  - name: cafe
    sectionName: http
  hostnames:
  - "cafe.example.com"
  rules:
  - matches:
    - path:
        type: PathPrefix
        value: /coffee
    filters:
    - type: RequestMirror
      requestMirror:
        backendRef:
          name: tea
          port: 80
    backendRefs:
    - name: coffee
      port: 80
EOF

Test the configuration:

You can send traffic using the external IP address and port saved earlier:

curl --resolve cafe.example.com:$GW_PORT:$GW_IP http://cafe.example.com:$GW_PORT/coffee

This request should receive a response from the coffee Pod:

Server address: 10.244.0.13:8080
Server name: coffee-676c9f8944-dxvkt

Now, check the logs of the tea application:

kubectl logs deployments/tea

You should see a log that looks similar to the following:

10.244.0.12 - - [17/Apr/2025:18:44:21 +0000] "GET /coffee HTTP/1.1" 200 158 "-" "curl/8.7.1" "127.0.0.1"

This shows that the request to /coffee was mirrored to the tea application.

See also

To learn more about request mirroring using the Gateway API, see the following resource:

• Gateway API request mirroring