feat(talos): add metrics docs

docs/talos/enable_metrics.md

@@ -0,0 +1,44 @@
+# Enable Kubernetes Metrics API
+
+By default the metrics API is not available on Talos Linux. This needs to be configured and installed.
+
+## Control Plane
+
+Create a patch for control plane nodes.
+
+```yaml
+machine:
+  kubelet:
+    extraArgs:
+      rotate-server-certificates: true
+
+  files:
+    - content: |
+        [metrics]
+          address = "0.0.0.0:11234"
+      path: /var/cri/conf.d/metrics.toml
+      op: create
+
+cluster:
+  extraManifests:
+    - https://raw.githubusercontent.com/alex1989hu/kubelet-serving-cert-approver/main/deploy/standalone-install.yaml
+    - https://github.com/kubernetes-sigs/metrics-server/releases/latest/download/components.yaml
+```
+
+## Workers
+
+Create a patch for worker nodes.
+
+```yaml
+machine:
+  kubelet:
+    extraArgs:
+      rotate-server-certificates: true
+
+  files:
+    - content: |
+        [metrics]
+          address = "0.0.0.0:11234"
+      path: /var/cri/conf.d/metrics.toml
+      op: create
+```