fixes

pkg/apis/autoscaling/v1alpha1/pa_lifecycle.go

@@ -216,9 +216,9 @@ func (pas *PodAutoscalerStatus) MarkScaleTargetInitialized() {
 	podCondSet.Manage(pas).MarkTrue(PodAutoscalerConditionScaleTargetInitialized)
 }
 
-// ScaleTargetNotScaledAfterFailure returns true if the PodAutoscaler's scale target has been
-// scaled successfully.
-func (pas *PodAutoscalerStatus) ScaleTargetNotScaledAfterFailure() bool {
+// ScaleTargetNotScaled returns true if the PodAutoscaler's scale target has failed
+// to scaled.
+func (pas *PodAutoscalerStatus) ScaleTargetNotScaled() bool {
 	return pas.GetCondition(PodAutoscalerConditionScaleTargetScaled).IsFalse()
 }
 

pkg/apis/serving/v1/revision_lifecycle.go

@@ -200,6 +200,13 @@ func (rs *RevisionStatus) PropagateAutoscalerStatus(ps *autoscalingv1alpha1.PodA
 		// that implies that |service.endpoints| > 0.
 		rs.MarkResourcesAvailableTrue()
 		rs.MarkContainerHealthyTrue()
+
+		// Mark resource unavailable if we are scaling back to zero, but we never achieved the required scale
+		// and deployment status was not updated properly by K8s. For example due to an image pull error.
+		if ps.ScaleTargetNotScaled() {
+			condScaled := ps.GetCondition(autoscalingv1alpha1.PodAutoscalerConditionScaleTargetScaled)
+			rs.MarkResourcesAvailableFalse(condScaled.Reason, condScaled.Message)
+		}
 	}
 
 	// Mark resource unavailable if we don't have a Service Name and the deployment is ready
@@ -234,13 +241,6 @@ func (rs *RevisionStatus) PropagateAutoscalerStatus(ps *autoscalingv1alpha1.PodA
 	case corev1.ConditionTrue:
 		rs.MarkActiveTrue()
 	}
-
-	// Mark resource unavailable if we scaled back to zero, but we never achieved the required scale
-	// and deployment status was not updated properly byt K8s. For example due to a temporary image pull error.
-	if ps.IsScaleTargetInitialized() && !resUnavailable && ps.ScaleTargetNotScaledAfterFailure() {
-		condScaled := ps.GetCondition(autoscalingv1alpha1.PodAutoscalerConditionScaleTargetScaled)
-		rs.MarkResourcesAvailableFalse(condScaled.Reason, condScaled.Message)
-	}
 }
 
 // ResourceNotOwnedMessage constructs the status message if ownership on the

pkg/reconciler/autoscaling/kpa/scaler.go

@@ -388,7 +388,7 @@ func (ks *scaler) scale(ctx context.Context, pa *autoscalingv1alpha1.PodAutoscal
 		if err != nil {
 			return desiredScale, fmt.Errorf("error getting pod counts: %w", err)
 		}
-		if ready == 0 {
+		if ready == 0 && currentScale > 0 {
 			var pod *corev1.Pod
 			pod, err = podCounter.GetAnyPod()
 			if err != nil {

pkg/reconciler/revision/table_test.go

@@ -41,6 +41,7 @@ import (
 	tracingconfig "knative.dev/pkg/tracing/config"
 	autoscalingv1alpha1 "knative.dev/serving/pkg/apis/autoscaling/v1alpha1"
 	defaultconfig "knative.dev/serving/pkg/apis/config"
+	"knative.dev/serving/pkg/apis/serving"
 	v1 "knative.dev/serving/pkg/apis/serving/v1"
 	"knative.dev/serving/pkg/autoscaler/config/autoscalerconfig"
 	servingclient "knative.dev/serving/pkg/client/injection/client"
@@ -744,6 +745,37 @@ func TestReconcile(t *testing.T) {
 			PodSpecPersistentVolumeClaim: defaultconfig.Enabled,
 			PodSpecPersistentVolumeWrite: defaultconfig.Enabled,
 		}}),
+	}, {
+		Name: "revision becomes not ready when PA reports a failed container",
+		Objects: []runtime.Object{
+			Revision("foo", "container-failed",
+				WithLogURL,
+				MarkRevisionReady,
+				withDefaultContainerStatuses(),
+				WithRevisionLabel(serving.RoutingStateLabelKey, "active"),
+			),
+			pa("foo", "container-failed",
+				WithPAStatusScaleTargetScaleFailures("ImagePullBackOff", "Back-off pulling image..."),
+				WithScaleTargetInitialized,
+				WithTraffic,
+				WithReachabilityReachable,
+				WithPAStatusService("something"),
+			),
+			readyDeploy(deploy(t, "foo", "container-failed")),
+			image("foo", "container-failed"),
+		},
+		Key: "foo/container-failed",
+		WantStatusUpdates: []clientgotesting.UpdateActionImpl{{
+			Object: Revision("foo", "container-failed",
+				WithLogURL,
+				MarkInactive("ImagePullBackOff", "Back-off pulling image..."),
+				MarkResourcesUnavailable("ImagePullBackOff", "Back-off pulling image..."),
+				MarkContainerHealthy(),
+				withDefaultContainerStatuses(),
+				WithRevisionObservedGeneration(1),
+				WithRevisionLabel(serving.RoutingStateLabelKey, "active"),
+			),
+		}},
 	}}
 
 	table.Test(t, MakeFactory(func(ctx context.Context, listers *Listers, _ configmap.Watcher) controller.Reconciler {

pkg/testing/functional.go

@@ -113,6 +113,13 @@ func WithScaleTargetScaleFailures(pa *autoscalingv1alpha1.PodAutoscaler, reason,
 	pa.Status.MarkWithScaleFailures(reason, message)
 }
 
+// WithPAStatusScaleTargetScaleFailures updates the PA to reflect that there were scale failures
+func WithPAStatusScaleTargetScaleFailures(reason, message string) PodAutoscalerOption {
+	return func(pa *autoscalingv1alpha1.PodAutoscaler) {
+		pa.Status.MarkWithScaleFailures(reason, message)
+	}
+}
+
 // WithPAStatusService annotates PA Status with the provided service name.
 func WithPAStatusService(svc string) PodAutoscalerOption {
 	return func(pa *autoscalingv1alpha1.PodAutoscaler) {

pkg/testing/v1/revision.go

@@ -158,6 +158,12 @@ func MarkContainerHealthyUnknown(reason string) RevisionOption {
 	}
 }
 
+func MarkContainerHealthy() RevisionOption {
+	return func(r *v1.Revision) {
+		r.Status.MarkContainerHealthyTrue()
+	}
+}
+
 // MarkProgressDeadlineExceeded calls the method of the same name on the Revision
 // with the message we expect the Revision Reconciler to pass.
 func MarkProgressDeadlineExceeded(message string) RevisionOption {