Return the error from validateOverhead in RuntimeClass#Validate

plugin/pkg/admission/runtimeclass/BUILD

@@ -32,6 +32,7 @@ go_test(
         "//staging/src/k8s.io/api/node/v1beta1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/api/resource:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/admission:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/authentication/user:go_default_library",
         "//staging/src/k8s.io/apiserver/pkg/util/feature:go_default_library",

plugin/pkg/admission/runtimeclass/admission.go

@@ -112,9 +112,10 @@ func (r *RuntimeClass) Validate(attributes admission.Attributes, o admission.Obj
 	if err != nil {
 		return err
 	}
-
 	if utilfeature.DefaultFeatureGate.Enabled(features.PodOverhead) {
-		err = validateOverhead(attributes, pod, runtimeClass)
+		if err = validateOverhead(attributes, pod, runtimeClass); err != nil {
+			return err
+		}
 	}
 
 	return nil
@@ -136,28 +137,17 @@ func (r *RuntimeClass) prepareObjects(attributes admission.Attributes) (pod *api
 	}
 
 	// get RuntimeClass object
-	runtimeClass, err = r.getRuntimeClass(pod, pod.Spec.RuntimeClassName)
+	if pod.Spec.RuntimeClassName != nil {
-	if err != nil {
+		runtimeClass, err = r.runtimeClassLister.Get(*pod.Spec.RuntimeClassName)
-		return pod, nil, err
+		if err != nil {
+			return pod, nil, err
+		}
 	}
 
 	// return the pod and runtimeClass. If no RuntimeClass is specified in PodSpec, runtimeClass will be nil
 	return pod, runtimeClass, nil
 }
 
-// getRuntimeClass will return a reference to the RuntimeClass object if it is found. If it cannot be found, or a RuntimeClassName
-// is not provided in the pod spec, *node.RuntimeClass returned will be nil
-func (r *RuntimeClass) getRuntimeClass(pod *api.Pod, runtimeClassName *string) (runtimeClass *v1beta1.RuntimeClass, err error) {
-
-	runtimeClass = nil
-
-	if runtimeClassName != nil {
-		runtimeClass, err = r.runtimeClassLister.Get(*runtimeClassName)
-	}
-
-	return runtimeClass, err
-}
-
 func setOverhead(a admission.Attributes, pod *api.Pod, runtimeClass *v1beta1.RuntimeClass) (err error) {
 
 	if runtimeClass != nil {

plugin/pkg/admission/runtimeclass/admission_test.go

@@ -21,6 +21,7 @@ import (
 	"k8s.io/api/node/v1beta1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/apiserver/pkg/authentication/user"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
@@ -154,9 +155,79 @@ func TestSetOverhead(t *testing.T) {
 		})
 	}
 }
+func NewObjectInterfacesForTest() admission.ObjectInterfaces {
+	scheme := runtime.NewScheme()
+	corev1.AddToScheme(scheme)
+	return admission.NewObjectInterfacesFromScheme(scheme)
+}
+
+func TestValidate(t *testing.T) {
+	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PodOverhead, true)()
+
+	tests := []struct {
+		name         string
+		runtimeClass *v1beta1.RuntimeClass
+		pod          *core.Pod
+		expectError  bool
+	}{
+		{
+			name: "No Overhead in RunntimeClass, Overhead set in pod",
+			runtimeClass: &v1beta1.RuntimeClass{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Handler:    "bar",
+			},
+			pod:         validPod("no-resource-req-no-overhead", 1, getGuaranteedRequirements(), true),
+			expectError: true,
+		},
+		{
+			name: "Non-matching Overheads",
+			runtimeClass: &v1beta1.RuntimeClass{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Handler:    "bar",
+				Overhead: &v1beta1.Overhead{
+					PodFixed: corev1.ResourceList{
+						corev1.ResourceName(corev1.ResourceCPU):    resource.MustParse("10"),
+						corev1.ResourceName(corev1.ResourceMemory): resource.MustParse("10G"),
+					},
+				},
+			},
+			pod:         validPod("no-resource-req-no-overhead", 1, core.ResourceRequirements{}, true),
+			expectError: true,
+		},
+		{
+			name: "Matching Overheads",
+			runtimeClass: &v1beta1.RuntimeClass{
+				ObjectMeta: metav1.ObjectMeta{Name: "foo"},
+				Handler:    "bar",
+				Overhead: &v1beta1.Overhead{
+					PodFixed: corev1.ResourceList{
+						corev1.ResourceName(corev1.ResourceCPU):    resource.MustParse("100m"),
+						corev1.ResourceName(corev1.ResourceMemory): resource.MustParse("1"),
+					},
+				},
+			},
+			pod:         validPod("no-resource-req-no-overhead", 1, core.ResourceRequirements{}, false),
+			expectError: false,
+		},
+	}
+	rt := NewRuntimeClass()
+	o := NewObjectInterfacesForTest()
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+
+			attrs := admission.NewAttributesRecord(tc.pod, nil, core.Kind("Pod").WithVersion("version"), tc.pod.Namespace, tc.pod.Name, core.Resource("pods").WithVersion("version"), "", admission.Create, &metav1.CreateOptions{}, false, &user.DefaultInfo{})
+
+			errs := rt.Validate(attrs, o)
+			if tc.expectError {
+				assert.NotEmpty(t, errs)
+			} else {
+				assert.Empty(t, errs)
+			}
+		})
+	}
+}
 
 func TestValidateOverhead(t *testing.T) {
-
 	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.PodOverhead, true)()
 
 	tests := []struct {