ACP-53276: Document disabling Ingress NGINX metrics

docs/en/solutions/How_to_Disable_Metrics_Port_for_Ingress_NGINX.md

@@ -0,0 +1,97 @@
+---
+kind:
+   - How To
+products:
+  - Alauda Container Platform
+ProductsVersion:
+   - 4.3.x and later
+tags:
+  - LB
+---
+
+# How to Disable the Metrics Port for Ingress NGINX
+
+## Overview
+
+This document describes how to disable the Prometheus metrics port for Ingress NGINX on Alauda Container Platform (ACP) 4.3.x and later.
+
+Ingress NGINX is managed by the `IngressNginx` custom resource. Configure metrics through the `IngressNginx` resource. Do not manually edit the generated Deployment, Service, or ServiceMonitor, because these resources are reconciled by the ingress-nginx operator.
+
+The required configuration is:
+
+```yaml
+spec:
+  controller:
+    metrics:
+      enabled: false
+```
+
+This setting is sufficient to disable the metrics configuration rendered by the operator. After reconciliation, the controller no longer receives the `--enable-metrics=true` argument, the metrics container port is removed from the generated workload, and metrics-related resources such as the metrics Service and ServiceMonitor are not rendered.
+
+:::note
+The metrics port is different from the Ingress NGINX health check endpoint used by liveness and readiness probes.
+:::
+
+## Prerequisites
+
+1. ACP 4.3.x or later.
+2. The ingress-nginx operator has been installed.
+3. At least one `IngressNginx` resource has been created.
+4. `kubectl` has been configured to access the cluster.
+
+## Procedure
+
+### Step 1: Find the IngressNginx resource
+
+Use the following command to list all Ingress NGINX instances:
+
+```bash
+kubectl get ingressnginxes.ingress-nginx.alauda.io -A
+```
+
+Example output:
+
+```text
+NAMESPACE                NAME       AGE
+ingress-nginx-operator   demo-all   145m
+```
+
+Set the namespace and name according to your environment:
+
+```bash
+export INGRESS_NGINX_NAMESPACE="ingress-nginx-operator"
+export INGRESS_NGINX_NAME="demo-all"
+```
+
+### Step 2: Disable metrics
+
+Patch `spec.controller.metrics.enabled` to `false`:
+
+```bash
+kubectl patch ingressnginxes.ingress-nginx.alauda.io "${INGRESS_NGINX_NAME}" \
+  -n "${INGRESS_NGINX_NAMESPACE}" \
+  --type merge \
+  -p '{
+    "spec": {
+      "controller": {
+        "metrics": {
+          "enabled": false
+        }
+      }
+    }
+  }'
+```
+
+Wait for the operator to reconcile the `IngressNginx` resource.
+
+### Step 3: Verify the controller argument
+
+Check the generated controller Deployment:
+
+```bash
+kubectl get deployment -n "${INGRESS_NGINX_NAMESPACE}" \
+  "${INGRESS_NGINX_NAME}-ingress-nginx-controller" \
+  -o jsonpath='{.spec.template.spec.containers[0].args}' | tr ' ' '\n' | grep -- '--enable-metrics=true'
+```
+
+Expected result: the command prints no output.