cmd/k8s-operator/deploy,k8s-operator: document that metrics are unstable (#11979)

Updates#11292

Signed-off-by: Irbe Krumina <irbe@tailscale.com>

cmd/k8s-operator/deploy/crds/tailscale.com_proxyclasses.yaml

@@ -39,7 +39,7 @@ spec:
               type: object
               properties:
                 metrics:
-                  description: Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation.
+                  description: Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation. Note that the metrics are currently considered unstable and will likely change in breaking ways in the future - we only recommend that you use those for debugging purposes.
                   type: object
                   required:
                     - enable

cmd/k8s-operator/deploy/manifests/operator.yaml

@@ -291,7 +291,7 @@ spec:
                         description: Specification of the desired state of the ProxyClass resource. https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#spec-and-status
                         properties:
                             metrics:
-                                description: Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation.
+                                description: Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation. Note that the metrics are currently considered unstable and will likely change in breaking ways in the future - we only recommend that you use those for debugging purposes.
                                 properties:
                                     enable:
                                         description: Setting enable to true will make the proxy serve Tailscale metrics at <pod-ip>:9001/debug/metrics. Defaults to false.

k8s-operator/api.md

@@ -603,7 +603,7 @@ Specification of the desired state of the ProxyClass resource. https://git.k8s.i
         <td><b><a href="#proxyclassspecmetrics">metrics</a></b></td>
         <td>object</td>
         <td>
-          Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation.<br/>
+          Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation. Note that the metrics are currently considered unstable and will likely change in breaking ways in the future - we only recommend that you use those for debugging purposes.<br/>
         </td>
         <td>false</td>
       </tr><tr>
@@ -622,7 +622,7 @@ Specification of the desired state of the ProxyClass resource. https://git.k8s.i
 
 
 
-Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation.
+Configuration for proxy metrics. Metrics are currently not supported for egress proxies and for Ingress proxies that have been configured with tailscale.com/experimental-forward-cluster-traffic-via-ingress annotation. Note that the metrics are currently considered unstable and will likely change in breaking ways in the future - we only recommend that you use those for debugging purposes.
 
 <table>
     <thead>

k8s-operator/apis/v1alpha1/types_proxyclass.go

@@ -57,7 +57,9 @@ type ProxyClassSpec struct {
 	// Configuration for proxy metrics. Metrics are currently not supported
 	// for egress proxies and for Ingress proxies that have been configured
 	// with tailscale.com/experimental-forward-cluster-traffic-via-ingress
-	// annotation.
+	// annotation. Note that the metrics are currently considered unstable
+	// and will likely change in breaking ways in the future - we only
+	// recommend that you use those for debugging purposes.
 	// +optional
 	Metrics *Metrics `json:"metrics,omitempty"`
 }