m/n/kubernetes/{clusternet,nfproxy}: log informer errors

Change-Id: I9ea1444c7042dd25c25cecc6b6da054554010a85
Reviewed-on: https://review.monogon.dev/c/monogon/+/1447
Reviewed-by: Lorenz Brun <lorenz@monogon.tech>
Tested-by: Jenkins CI
diff --git a/metropolis/node/kubernetes/clusternet/clusternet.go b/metropolis/node/kubernetes/clusternet/clusternet.go
index 3cf2535..3c86361 100644
--- a/metropolis/node/kubernetes/clusternet/clusternet.go
+++ b/metropolis/node/kubernetes/clusternet/clusternet.go
@@ -247,6 +247,9 @@
 	}
 
 	nodeInformer := s.InformerFactory.Core().V1().Nodes()
+	nodeInformer.Informer().SetWatchErrorHandler(func(_ *cache.Reflector, err error) {
+		supervisor.Logger(ctx).Errorf("node informer watch error: %v", err)
+	})
 	nodeInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
 		AddFunc: func(new interface{}) {
 			newNode, ok := new.(*corev1.Node)