catch some unhandled errors

cmd/kube-apiserver/app/aggregator.go

@@ -66,12 +66,15 @@ func createAggregatorConfig(
 
 	// override genericConfig.AdmissionControl with kube-aggregator's scheme,
 	// because aggregator apiserver should use its own scheme to convert its own resources.
-	commandOptions.Admission.ApplyTo(
+	err := commandOptions.Admission.ApplyTo(
 		&genericConfig,
 		externalInformers,
 		genericConfig.LoopbackClientConfig,
 		aggregatorscheme.Scheme,
 		pluginInitializers...)
+	if err != nil {
+		return nil, err
+	}
 
 	// copy the etcd options so we don't mutate originals.
 	etcdOptions := *commandOptions.Etcd
@@ -87,7 +90,6 @@ func createAggregatorConfig(
 		return nil, err
 	}
 
-	var err error
 	var certBytes, keyBytes []byte
 	if len(commandOptions.ProxyClientCertFile) > 0 && len(commandOptions.ProxyClientKeyFile) > 0 {
 		certBytes, err = ioutil.ReadFile(commandOptions.ProxyClientCertFile)
@@ -133,7 +135,7 @@ func createAggregatorServer(aggregatorConfig *aggregatorapiserver.Config, delega
 		apiExtensionInformers.Apiextensions().InternalVersion().CustomResourceDefinitions(),
 		autoRegistrationController)
 
-	aggregatorServer.GenericAPIServer.AddPostStartHook("kube-apiserver-autoregistration", func(context genericapiserver.PostStartHookContext) error {
+	err = aggregatorServer.GenericAPIServer.AddPostStartHook("kube-apiserver-autoregistration", func(context genericapiserver.PostStartHookContext) error {
 		go crdRegistrationController.Run(5, context.StopCh)
 		go func() {
 			// let the CRD controller process the initial set of CRDs before starting the autoregistration controller.
@@ -146,14 +148,20 @@ func createAggregatorServer(aggregatorConfig *aggregatorapiserver.Config, delega
 		}()
 		return nil
 	})
+	if err != nil {
+		return nil, err
+	}
 
-	aggregatorServer.GenericAPIServer.AddHealthzChecks(
+	err = aggregatorServer.GenericAPIServer.AddHealthzChecks(
 		makeAPIServiceAvailableHealthzCheck(
 			"autoregister-completion",
 			apiServices,
 			aggregatorServer.APIRegistrationInformers.Apiregistration().InternalVersion().APIServices(),
 		),
 	)
+	if err != nil {
+		return nil, err
+	}
 
 	return aggregatorServer, nil
 }

cmd/kube-apiserver/app/apiextensions.go

@@ -48,12 +48,15 @@ func createAPIExtensionsConfig(
 
 	// override genericConfig.AdmissionControl with apiextensions' scheme,
 	// because apiextentions apiserver should use its own scheme to convert resources.
-	commandOptions.Admission.ApplyTo(
+	err := commandOptions.Admission.ApplyTo(
 		&genericConfig,
 		externalInformers,
 		genericConfig.LoopbackClientConfig,
 		apiextensionsapiserver.Scheme,
 		pluginInitializers...)
+	if err != nil {
+		return nil, err
+	}
 
 	// copy the etcd options so we don't mutate originals.
 	etcdOptions := *commandOptions.Etcd