Use semantic equality in client ca post start hook

pkg/master/BUILD

@@ -104,6 +104,7 @@ go_library(
         "//staging/src/k8s.io/api/storage/v1:go_default_library",
         "//staging/src/k8s.io/api/storage/v1alpha1:go_default_library",
         "//staging/src/k8s.io/api/storage/v1beta1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/api/equality:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/errors:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/util/intstr:go_default_library",

pkg/master/client_ca_hook.go

@@ -19,10 +19,10 @@ package master
 import (
 	"encoding/json"
 	"fmt"
-	"reflect"
 	"time"
 
 	corev1 "k8s.io/api/core/v1"
+	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
@@ -132,7 +132,7 @@ func writeConfigMap(client corev1client.ConfigMapsGetter, name string, data map[
 		return err
 	}
 
-	if !reflect.DeepEqual(existing.Data, data) {
+	if !apiequality.Semantic.DeepEqual(existing.Data, data) {
 		existing.Data = data
 		_, err = client.ConfigMaps(metav1.NamespaceSystem).Update(existing)
 	}

test/integration/apiserver/admissionwebhook/BUILD

@@ -4,6 +4,7 @@ go_test(
     name = "go_default_test",
     srcs = [
         "admission_test.go",
+        "broken_webhook_test.go",
         "main_test.go",
     ],
     tags = [
@@ -12,8 +13,10 @@ go_test(
     ],
     deps = [
         "//cmd/kube-apiserver/app/options:go_default_library",
+        "//cmd/kube-apiserver/app/testing:go_default_library",
         "//staging/src/k8s.io/api/admission/v1beta1:go_default_library",
         "//staging/src/k8s.io/api/admissionregistration/v1beta1:go_default_library",
+        "//staging/src/k8s.io/api/apps/v1:go_default_library",
         "//staging/src/k8s.io/api/apps/v1beta1:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/api/extensions/v1beta1:go_default_library",

test/integration/apiserver/admissionwebhook/broken_webhook_test.go

@@ -0,0 +1,183 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package admissionwebhook
+
+import (
+	"fmt"
+	"testing"
+	"time"
+
+	admissionregistrationv1beta1 "k8s.io/api/admissionregistration/v1beta1"
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes"
+	kubeapiservertesting "k8s.io/kubernetes/cmd/kube-apiserver/app/testing"
+	"k8s.io/kubernetes/test/integration/framework"
+)
+
+var (
+	brokenWebhookName    = "integration-broken-webhook-test-webhook-config"
+	deploymentNamePrefix = "integration-broken-webhook-test-deployment"
+)
+
+func TestBrokenWebhook(t *testing.T) {
+	var tearDownFn kubeapiservertesting.TearDownFunc
+	defer func() {
+		if tearDownFn != nil {
+			tearDownFn()
+		}
+	}()
+
+	etcdConfig := framework.SharedEtcd()
+	server := kubeapiservertesting.StartTestServerOrDie(t, nil, nil, etcdConfig)
+	tearDownFn = server.TearDownFn
+
+	client, err := kubernetes.NewForConfig(server.ClientConfig)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	t.Logf("Creating Deployment to ensure apiserver is functional")
+	_, err = client.AppsV1().Deployments("default").Create(exampleDeployment(generateDeploymentName(0)))
+	if err != nil {
+		t.Fatalf("Failed to create deployment: %v", err)
+	}
+
+	t.Logf("Creating Broken Webhook that will block all operations on all objects")
+	_, err = client.AdmissionregistrationV1beta1().ValidatingWebhookConfigurations().Create(brokenWebhookConfig(brokenWebhookName))
+	if err != nil {
+		t.Fatalf("Failed to register broken webhook: %v", err)
+	}
+
+	// There is no guarantee on how long it takes the apiserver to honor the configuration and there is
+	// no API to determine if the configuration is being honored, so we will just wait 10s, which is long enough
+	// in most cases.
+	time.Sleep(10 * time.Second)
+
+	// test whether the webhook blocks requests
+	t.Logf("Attempt to create Deployment which should fail due to the webhook")
+	_, err = client.AppsV1().Deployments("default").Create(exampleDeployment(generateDeploymentName(1)))
+	if err == nil {
+		t.Fatalf("Expected the broken webhook to cause creating a deployment to fail, but it succeeded.")
+	}
+
+	t.Logf("Restarting apiserver")
+	tearDownFn = nil
+	server.TearDownFn()
+	server = kubeapiservertesting.StartTestServerOrDie(t, nil, nil, etcdConfig)
+	tearDownFn = server.TearDownFn
+
+	client, err = kubernetes.NewForConfig(server.ClientConfig)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+
+	// test whether the webhook still blocks requests after restarting
+	t.Logf("Attempt again to create Deployment which should fail due to the webhook")
+	_, err = client.AppsV1().Deployments("default").Create(exampleDeployment(generateDeploymentName(2)))
+	if err == nil {
+		t.Fatalf("Expected the broken webhook to cause creating a deployment to fail, but it succeeded.")
+	}
+
+	t.Logf("Deleting the broken webhook to fix the cluster")
+	err = client.AdmissionregistrationV1beta1().ValidatingWebhookConfigurations().Delete(brokenWebhookName, nil)
+	if err != nil {
+		t.Fatalf("Failed to delete broken webhook: %v", err)
+	}
+
+	// The webhook deletion is honored in 10s.
+	time.Sleep(10 * time.Second)
+
+	// test if the deleted webhook no longer blocks requests
+	t.Logf("Creating Deployment to ensure webhook is deleted")
+	_, err = client.AppsV1().Deployments("default").Create(exampleDeployment(generateDeploymentName(3)))
+	if err != nil {
+		t.Fatalf("Failed to create deployment: %v", err)
+	}
+}
+
+func generateDeploymentName(suffix int) string {
+	return fmt.Sprintf("%v-%v", deploymentNamePrefix, suffix)
+}
+
+func exampleDeployment(name string) *appsv1.Deployment {
+	var replicas int32 = 1
+	return &appsv1.Deployment{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Deployment",
+			APIVersion: "apps/v1",
+		},
+		ObjectMeta: metav1.ObjectMeta{
+			Namespace: "default",
+			Name:      name,
+		},
+		Spec: appsv1.DeploymentSpec{
+			Replicas: &replicas,
+			Selector: &metav1.LabelSelector{
+				MatchLabels: map[string]string{"foo": "bar"},
+			},
+			Template: corev1.PodTemplateSpec{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: map[string]string{"foo": "bar"},
+				},
+				Spec: corev1.PodSpec{
+					Containers: []corev1.Container{
+						{
+							Name:  "foo",
+							Image: "foo",
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func brokenWebhookConfig(name string) *admissionregistrationv1beta1.ValidatingWebhookConfiguration {
+	var path string
+	var failurePolicy admissionregistrationv1beta1.FailurePolicyType = admissionregistrationv1beta1.Fail
+	return &admissionregistrationv1beta1.ValidatingWebhookConfiguration{
+		ObjectMeta: metav1.ObjectMeta{
+			Name: name,
+		},
+		Webhooks: []admissionregistrationv1beta1.Webhook{
+			{
+				Name: "broken-webhook.k8s.io",
+				Rules: []admissionregistrationv1beta1.RuleWithOperations{{
+					Operations: []admissionregistrationv1beta1.OperationType{admissionregistrationv1beta1.OperationAll},
+					Rule: admissionregistrationv1beta1.Rule{
+						APIGroups:   []string{"*"},
+						APIVersions: []string{"*"},
+						Resources:   []string{"*/*"},
+					},
+				}},
+				// This client config references a non existent service
+				// so it should always fail.
+				ClientConfig: admissionregistrationv1beta1.WebhookClientConfig{
+					Service: &admissionregistrationv1beta1.ServiceReference{
+						Namespace: "default",
+						Name:      "invalid-webhook-service",
+						Path:      &path,
+					},
+					CABundle: nil,
+				},
+				FailurePolicy: &failurePolicy,
+			},
+		},
+	}
+}