[release 0.17] Cherrypick #79 and #82 (#86)

* Retry Creates on resourcequota conflicts. (#79)

This follows @vaikas PR here: knative/eventing#3215

The kubernetes issue is tracked here: kubernetes/kubernetes#67761

Fixes: knative/test-infra#2346

* Include Get in the UpdateRetry. (#82)

This adjusts the update retry around the ingress update in #79 to include the Get.

The original change was to guard against issues updating gke-resource-quotas, but there is a low incidence of conflicts simply updating the kingress itself.

Here's an example from net-contour:

```
=== CONT  TestIngressConformance/5/update
    update.go:88: Error updating Ingress: Operation cannot be fulfilled on ingresses.networking.internal.knative.dev "ingress-conformance-5-update-eghinekn": the object has been modified; please apply your changes to the latest version and try again
```

However, to resolve this, we actually have to refetch the kingress shell we've stuck the desired IngressSpec into otherwise it will just retry until it has exhausted its attempts because the resourceVersion we're sending back is never changed (and this is what the optimistic concurrency keys off of).

test/conformance/ingress/util.go

@@ -52,6 +52,7 @@ import (
 	"knative.dev/networking/test"
 	"knative.dev/networking/test/types"
 	"knative.dev/pkg/network"
+	"knative.dev/pkg/reconciler"
 	pkgTest "knative.dev/pkg/test"
 	"knative.dev/pkg/test/logging"
 )
@@ -535,8 +536,10 @@ func createService(t *testing.T, clients *test.Clients, svc *corev1.Service) con
 	test.CleanupOnInterrupt(func() {
 		clients.KubeClient.Kube.CoreV1().Services(svc.Namespace).Delete(svc.Name, &metav1.DeleteOptions{})
 	})
-	svc, err := clients.KubeClient.Kube.CoreV1().Services(svc.Namespace).Create(svc)
-	if err != nil {
+	if err := reconciler.RetryUpdateConflicts(func(attempts int) error {
+		_, err := clients.KubeClient.Kube.CoreV1().Services(svc.Namespace).Create(svc)
+		return err
+	}); err != nil {
 		t.Fatal("Error creating Service:", err)
 	}
 
@@ -554,8 +557,10 @@ func createPodAndService(t *testing.T, clients *test.Clients, pod *corev1.Pod, s
 	t.Helper()
 
 	test.CleanupOnInterrupt(func() { clients.KubeClient.Kube.CoreV1().Pods(pod.Namespace).Delete(pod.Name, &metav1.DeleteOptions{}) })
-	pod, err := clients.KubeClient.Kube.CoreV1().Pods(pod.Namespace).Create(pod)
-	if err != nil {
+	if err := reconciler.RetryUpdateConflicts(func(attempts int) error {
+		_, err := clients.KubeClient.Kube.CoreV1().Pods(pod.Namespace).Create(pod)
+		return err
+	}); err != nil {
 		t.Fatal("Error creating Pod:", err)
 	}
 	cancel := func() {
@@ -568,8 +573,10 @@ func createPodAndService(t *testing.T, clients *test.Clients, pod *corev1.Pod, s
 	test.CleanupOnInterrupt(func() {
 		clients.KubeClient.Kube.CoreV1().Services(svc.Namespace).Delete(svc.Name, &metav1.DeleteOptions{})
 	})
-	svc, err = clients.KubeClient.Kube.CoreV1().Services(svc.Namespace).Create(svc)
-	if err != nil {
+	if err := reconciler.RetryUpdateConflicts(func(attempts int) error {
+		_, err := clients.KubeClient.Kube.CoreV1().Services(svc.Namespace).Create(svc)
+		return err
+	}); err != nil {
 		cancel()
 		t.Fatal("Error creating Service:", err)
 	}
@@ -621,8 +628,10 @@ func CreateIngress(t *testing.T, clients *test.Clients, spec v1alpha1.IngressSpe
 		Spec: spec,
 	}
 	test.CleanupOnInterrupt(func() { clients.NetworkingClient.Ingresses.Delete(ing.Name, &metav1.DeleteOptions{}) })
-	ing, err := clients.NetworkingClient.Ingresses.Create(ing)
-	if err != nil {
+	if err := reconciler.RetryUpdateConflicts(func(attempts int) (err error) {
+		ing, err = clients.NetworkingClient.Ingresses.Create(ing)
+		return err
+	}); err != nil {
 		t.Fatal("Error creating Ingress:", err)
 	}
 
@@ -682,14 +691,17 @@ func CreateIngressReady(t *testing.T, clients *test.Clients, spec v1alpha1.Ingre
 func UpdateIngress(t *testing.T, clients *test.Clients, name string, spec v1alpha1.IngressSpec) {
 	t.Helper()
 
-	ing, err := clients.NetworkingClient.Ingresses.Get(name, metav1.GetOptions{})
-	if err != nil {
-		t.Fatal("Error getting Ingress:", err)
-	}
+	if err := reconciler.RetryUpdateConflicts(func(attempts int) error {
+		ing, err := clients.NetworkingClient.Ingresses.Get(name, metav1.GetOptions{})
+		if err != nil {
+			return err
+		}
 
-	ing.Spec = spec
-	if _, err := clients.NetworkingClient.Ingresses.Update(ing); err != nil {
-		t.Fatal("Error updating Ingress:", err)
+		ing.Spec = spec
+		_, err = clients.NetworkingClient.Ingresses.Update(ing)
+		return err
+	}); err != nil {
+		t.Fatal("Error fetching and updating Ingress:", err)
 	}
 }