kube-scheduler: compatibility with ServerSideApply

avoid moving Pods that have been assumed back to the scheduling queue in
case they have annotations modified with ServerSideApply, which causes
Pod.ObjectMeta.ManagedFields to be modified automatically

Author: fabiokung

pkg/scheduler/eventhandlers.go

@@ -335,6 +335,9 @@ func (sched *Scheduler) skipPodUpdate(pod *v1.Pod) bool {
 		// Annotations must be excluded for the reasons described in
 		// https://github.com/kubernetes/kubernetes/issues/52914.
 		p.Annotations = nil
+		// Same as above, when annotations are modified with ServerSideApply,
+		// ManagedFields may also change and must be excluded
+		p.ManagedFields = nil
 		return p
 	}
 	assumedPodCopy, podCopy := f(assumedPod), f(pod)

pkg/scheduler/eventhandlers_test.go

@@ -80,6 +80,85 @@ func TestSkipPodUpdate(t *testing.T) {
 			},
 			expected: true,
 		},
+		{
+			name: "with ServerSideApply changes on Annotations",
+			pod: &v1.Pod{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:            "pod-0",
+					Annotations:     map[string]string{"a": "b"},
+					ResourceVersion: "0",
+					ManagedFields: []metav1.ManagedFieldsEntry{
+						{
+							Manager:    "some-actor",
+							Operation:  metav1.ManagedFieldsOperationApply,
+							APIVersion: "v1",
+							FieldsType: "FieldsV1",
+							FieldsV1: &metav1.FieldsV1{
+								Raw: []byte(`
+									"f:metadata": {
+									  "f:annotations": {
+										"f:a: {}
+									  }
+									}
+								`),
+							},
+						},
+					},
+				},
+				Spec: v1.PodSpec{
+					NodeName: "node-0",
+				},
+			},
+			isAssumedPodFunc: func(*v1.Pod) bool {
+				return true
+			},
+			getPodFunc: func(*v1.Pod) *v1.Pod {
+				return &v1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:            "pod-0",
+						Annotations:     map[string]string{"a": "c", "d": "e"},
+						ResourceVersion: "1",
+						ManagedFields: []metav1.ManagedFieldsEntry{
+							{
+								Manager:    "some-actor",
+								Operation:  metav1.ManagedFieldsOperationApply,
+								APIVersion: "v1",
+								FieldsType: "FieldsV1",
+								FieldsV1: &metav1.FieldsV1{
+									Raw: []byte(`
+										"f:metadata": {
+										  "f:annotations": {
+											"f:a: {}
+											"f:d: {}
+										  }
+										}
+									`),
+								},
+							},
+							{
+								Manager:    "some-actor",
+								Operation:  metav1.ManagedFieldsOperationApply,
+								APIVersion: "v1",
+								FieldsType: "FieldsV1",
+								FieldsV1: &metav1.FieldsV1{
+									Raw: []byte(`
+										"f:metadata": {
+										  "f:annotations": {
+											"f:a: {}
+										  }
+										}
+									`),
+								},
+							},
+						},
+					},
+					Spec: v1.PodSpec{
+						NodeName: "node-1",
+					},
+				}
+			},
+			expected: true,
+		},
 		{
 			name: "with changes on Labels",
 			pod: &v1.Pod{