Merge pull request #56971 from derekwaynecarr/limit-range-ignore-terminating-pods

Automatic merge from submit-queue (batch tested with PRs 56971, 57570, 57830, 57742). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

LimitRange ignores objects previously marked for deletion

**What this PR does / why we need it**:
A `LimitRange` added to a namespace after it has pods can prevent terminating pods from being deleted if they do not conform to the min/max criteria.

xref https://bugzilla.redhat.com/show_bug.cgi?id=1509309

Fixes https://github.com/kubernetes/kubernetes/issues/57201

```release-note
NONE
```

plugin/pkg/admission/limitranger/admission.go

@@ -113,6 +113,18 @@ func (l *LimitRanger) runLimitFunc(a admission.Attributes, limitFn func(limitRan
 		}
 	}
 
+	// ignore all objects marked for deletion
+	oldObj := a.GetOldObject()
+	if oldObj != nil {
+		oldAccessor, err := meta.Accessor(oldObj)
+		if err != nil {
+			return admission.NewForbidden(a, err)
+		}
+		if oldAccessor.GetDeletionTimestamp() != nil {
+			return nil
+		}
+	}
+
 	items, err := l.GetLimitRanges(a)
 	if err != nil {
 		return err

plugin/pkg/admission/limitranger/admission_test.go

@@ -733,6 +733,15 @@ func TestLimitRangerAdmitPod(t *testing.T) {
 	if err != nil {
 		t.Errorf("Should have ignored calls to any subresource of pod %v", err)
 	}
+
+	// a pod that is undergoing termination should never be blocked
+	terminatingPod := validPod("terminatingPod", 1, api.ResourceRequirements{})
+	now := metav1.Now()
+	terminatingPod.DeletionTimestamp = &now
+	err = handler.Validate(admission.NewAttributesRecord(&terminatingPod, &terminatingPod, api.Kind("Pod").WithVersion("version"), limitRange.Namespace, "terminatingPod", api.Resource("pods").WithVersion("version"), "", admission.Update, nil))
+	if err != nil {
+		t.Errorf("LimitRange should ignore a pod marked for termination")
+	}
 }
 
 // newMockClientForTest creates a mock client that returns a client configured for the specified list of limit ranges