pkg/endpoint: reduce cardinality of prometheus labels

If the controller that is used for label resolution fails, the
prometheus metrics will increase its cardinality since the uniquely
controller name was being used as a prometheus label. To avoid this, we
will reference these warnings with a common subsystem name,
'resolve-labels'.

Fixes: a31ab29 ("endpoint: Run labels controller under ep manager")
Signed-off-by: André Martins <andre@cilium.io>

pkg/endpoint/endpoint.go

@@ -1645,7 +1645,8 @@ type MetadataResolverCB func(ns, podName string) (pod *slim_corev1.Pod, _ []slim
 // will handle updates (such as pkg/k8s/watchers informers).
 func (e *Endpoint) RunMetadataResolver(resolveMetadata MetadataResolverCB) {
 	done := make(chan struct{})
-	controllerName := fmt.Sprintf("resolve-labels-%s", e.GetK8sNamespaceAndPodName())
+	const controllerPrefix = "resolve-labels"
+	controllerName := fmt.Sprintf("%s-%s", controllerPrefix, e.GetK8sNamespaceAndPodName())
 	go func() {
 		select {
 		case <-done:
@@ -1661,7 +1662,7 @@ func (e *Endpoint) RunMetadataResolver(resolveMetadata MetadataResolverCB) {
 				ns, podName := e.GetK8sNamespace(), e.GetK8sPodName()
 				pod, cp, identityLabels, info, _, err := resolveMetadata(ns, podName)
 				if err != nil {
-					e.Logger(controllerName).WithError(err).Warning("Unable to fetch kubernetes labels")
+					e.Logger(controllerPrefix).WithError(err).Warning("Unable to fetch kubernetes labels")
 					return err
 				}
 				e.SetPod(pod)