k8s/watchers: warn when endpoint label update fails on pod update

Currently, failure to update endpoint labels based on pod labels on pod
update is silently ignored by the callers or only reflected in error
count metrics. Report a warning to clearly indicate that pod and
endpoint labels might be out of sync.

Signed-off-by: Tobias Klauser <tobias@cilium.io>

pkg/k8s/watchers/pod.go

@@ -403,6 +403,12 @@ func (k *K8sWatcher) updateK8sPodV1(oldK8sPod, newK8sPod *slim_corev1.Pod) error
 		if labelsChanged {
 			err := podEP.UpdateLabelsFrom(oldPodLabels, newPodLabels, labels.LabelSourceK8s)
 			if err != nil {
+				log.WithFields(logrus.Fields{
+					logfields.K8sPodName:   newK8sPod.ObjectMeta.Name,
+					logfields.K8sNamespace: newK8sPod.ObjectMeta.Namespace,
+					logfields.EndpointID:   podEP.GetID(),
+					logfields.Labels:       newPodLabels,
+				}).WithError(err).Warning("Unable to update endpoint labels on pod update")
 				return err
 			}