test deployment failures don't drop traffic on upgrade

test/upgrade/continual.go

@@ -22,6 +22,7 @@ import pkgupgrade "knative.dev/pkg/test/upgrade"
 func ContinualTests() []pkgupgrade.BackgroundOperation {
 	return []pkgupgrade.BackgroundOperation{
 		ProbeTest(),
+		DeploymentFailureProbeTest(),
 		AutoscaleSustainingTest(),
 		AutoscaleSustainingWithTBCTest(),
 	}

test/upgrade/deployment_failure.go

@@ -0,0 +1,122 @@
+/*
+Copyright 2024 The Knative 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 upgrade
+
+import (
+	"context"
+
+	admissionv1 "k8s.io/api/admissionregistration/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"knative.dev/pkg/ptr"
+	"knative.dev/pkg/test/helpers"
+	logstream "knative.dev/pkg/test/logstream/v2"
+	pkgupgrade "knative.dev/pkg/test/upgrade"
+	"knative.dev/serving/pkg/apis/autoscaling"
+	v1 "knative.dev/serving/pkg/apis/serving/v1"
+	"knative.dev/serving/test"
+	"knative.dev/serving/test/e2e"
+	v1test "knative.dev/serving/test/v1"
+)
+
+func DeploymentFailureProbeTest() pkgupgrade.BackgroundOperation {
+	var clients *test.Clients
+	var names *test.ResourceNames
+	var prober test.Prober
+	var canceler logstream.Canceler = func() {}
+
+	return pkgupgrade.NewBackgroundVerification("DeploymentFailureProbeTest", func(c pkgupgrade.Context) {
+		c.T.Log("Creating Service")
+		ctx := context.Background()
+
+		clients = e2e.Setup(c.T) // This one uses the default namespace `test.ServingFlags.TestNamespace`
+		names = &test.ResourceNames{
+			Service: "deployment-upgrade-failure",
+			Image:   test.HelloWorld,
+		}
+
+		if !test.ServingFlags.DisableLogStream {
+			canceler = streamLogs(c.T, clients, names.Service)
+		}
+
+		resources, err := v1test.CreateServiceReady(c.T, clients, names, func(s *v1.Service) {
+			s.Spec.Template.Labels = map[string]string{
+				autoscaling.MinScaleAnnotation.Key(): "1",
+				autoscaling.MaxScaleAnnotation.Key(): "1",
+			}
+		})
+
+		if err != nil {
+			c.T.Fatal("Failed to create Service:", err)
+		}
+
+		url := resources.Service.Status.URL.URL()
+		// This polls until we get a 200 with the right body.
+		assertServiceResourcesUpdated(c.T, clients, *names, url, test.PizzaPlanetText1)
+
+		transport := test.AddRootCAtoTransport(context.Background(), c.T.Logf, clients, test.ServingFlags.HTTPS)
+		prober = test.RunRouteProber(c.T.Logf, clients, url, transport)
+
+		// Setup webhook that fails when deployment is updated
+		// Failing to update the Deployment shouldn't cause a traffic drop
+		// note: the deployment is only updated if the controllers change the spec
+		//       and this happens when the queue proxy image is changed when upgrading
+		c.T.Log("Creating Failing Webhook")
+		noSideEffects := admissionv1.SideEffectClassNone
+
+		selector := &metav1.LabelSelector{
+			MatchLabels: map[string]string{
+				"serving.knative.dev/service": names.Service,
+			},
+		}
+
+		// Create a broken webhook that breaks scheduling Pods
+		_, err = clients.KubeClient.AdmissionregistrationV1().MutatingWebhookConfigurations().Create(
+			ctx,
+			&admissionv1.MutatingWebhookConfiguration{
+				ObjectMeta: metav1.ObjectMeta{
+					Name: "broken-webhook",
+				},
+				Webhooks: []admissionv1.MutatingWebhook{{
+					AdmissionReviewVersions: []string{"v1"},
+					Name:                    "webhook.non-existing.dev",
+					ClientConfig: admissionv1.WebhookClientConfig{
+						Service: &admissionv1.ServiceReference{
+							Name:      helpers.AppendRandomString("non-existing"),
+							Namespace: helpers.AppendRandomString("non-existing"),
+						},
+					},
+					ObjectSelector: selector,
+					TimeoutSeconds: ptr.Int32(5),
+					SideEffects:    &noSideEffects,
+					Rules: []admissionv1.RuleWithOperations{{
+						Operations: []admissionv1.OperationType{"CREATE"},
+						Rule: admissionv1.Rule{
+							APIGroups:   []string{""}, // core
+							APIVersions: []string{"v1"},
+							Resources:   []string{"pods"},
+						},
+					}},
+				}},
+			},
+			metav1.CreateOptions{},
+		)
+	}, func(c pkgupgrade.Context) {
+		// Verify
+		test.EnsureTearDown(c.T, clients, names)
+		test.AssertProberSLO(c.T, prober, *successFraction)
+		c.T.Cleanup(canceler)
+	})
+}