From 716cea4416754b92ba7a547df631aac07f84fff7 Mon Sep 17 00:00:00 2001
From: Saylor Berman <s.berman@f5.com>
Date: Thu, 17 Apr 2025 12:50:12 -0600
Subject: [PATCH 1/2] Add NGF request mirror doc

NGF is adding the capability for users to configure request mirroring. This adds a guide explaining how a user can set this up.
---
 .../ngf/how-to/traffic-management/mirror.md   | 214 ++++++++++++++++++
 1 file changed, 214 insertions(+)
 create mode 100644 content/ngf/how-to/traffic-management/mirror.md

diff --git a/content/ngf/how-to/traffic-management/mirror.md b/content/ngf/how-to/traffic-management/mirror.md
new file mode 100644
index 00000000..8ca7a5c2
--- /dev/null
+++ b/content/ngf/how-to/traffic-management/mirror.md
@@ -0,0 +1,214 @@
+---
+title: Configure Request Mirroring
+weight: 700
+toc: true
+type: how-to
+product: NGF
+docs: DOCS-000
+---
+
+Learn how to mirror your HTTP or gRPC traffic using NGINX Gateway Fabric.
+
+---
+
+## Overview
+
+[HTTPRoute](https://gateway-api.sigs.k8s.io/api-types/httproute/) and [GRPCRoute](https://gateway-api.sigs.k8s.io/api-types/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:
+
+   ```text
+   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:
+
+```yaml
+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:
+
+```shell
+kubectl get pods,svc
+```
+
+Your output should include the pods and services for **coffee** and **tea**:
+
+```text
+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:
+
+```yaml
+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:
+
+```yaml
+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:
+
+```shell
+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:
+
+```text
+Server address: 10.244.0.13:8080
+Server name: coffee-676c9f8944-dxvkt
+```
+
+Now, check the logs of the **tea** application:
+
+```shell
+kubectl logs deployments/tea
+```
+
+You should see a log that looks similar to the following:
+
+```text
+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](https://gateway-api.sigs.k8s.io/guides/http-request-mirroring/)

From 116e45a6e700f14f9832f7bc53a80f8d640c6289 Mon Sep 17 00:00:00 2001
From: Saylor Berman <s.berman@f5.com>
Date: Fri, 18 Apr 2025 14:33:31 -0600
Subject: [PATCH 2/2] Update compat doc

---
 content/ngf/overview/gateway-api-compatibility.md | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/content/ngf/overview/gateway-api-compatibility.md b/content/ngf/overview/gateway-api-compatibility.md
index d68e34de..4e08a90d 100644
--- a/content/ngf/overview/gateway-api-compatibility.md
+++ b/content/ngf/overview/gateway-api-compatibility.md
@@ -178,7 +178,8 @@ See the [static-mode]({{< ref "/ngf/reference/cli-help.md#static-mode">}}) comma
       - `requestHeaderModifier`: Supported. If multiple filters are configured, NGINX Gateway Fabric will choose the first and ignore the rest.
       - `urlRewrite`: Supported. If multiple filters are configured, NGINX Gateway Fabric will choose the first and ignore the rest. Incompatible with `requestRedirect`.
       - `responseHeaderModifier`: Supported. If multiple filters are configured, NGINX Gateway Fabric will choose the first and ignore the rest.
-      - `requestMirror`, `extensionRef`: Not supported.
+      - `requestMirror`: Supported. Multiple mirrors can be specified.
+      - `extensionRef`: Supported for SnippetsFilters.
     - `backendRefs`: Partially supported. Backend ref `filters` are not supported.
 - `status`
   - `parents`
@@ -226,7 +227,8 @@ See the [static-mode]({{< ref "/ngf/reference/cli-help.md#static-mode">}}) comma
       - `type`: Supported.
       - `requestHeaderModifier`: Supported. If multiple filters are configured, NGINX Gateway Fabric will choose the first and ignore the rest.
       - `responseHeaderModifier`: Supported. If multiple filters are configured, NGINX Gateway Fabric will choose the first and ignore the rest.
-      - `requestMirror`, `extensionRef`: Not supported.
+      - `requestMirror`: Supported. Multiple mirrors can be specified.
+      - `extensionRef`: Supported for SnippetsFilters.
     - `backendRefs`: Partially supported. Backend ref `filters` are not supported.
 - `status`
   - `parents`