Return Skip in InterPodAffinity#PreScore under specific conditions

This commit updates the InterPodAffinity PreScore to return a Skip status when the following conditions are met:
1. There are no nodes to score.
2. The incoming pod has no inter-pod affinities && the `IgnorePreferredTermsOfExistingPods` option is enabled.

Signed-off-by: utam0k <k0ma@utam0k.jp>

pkg/scheduler/framework/plugins/interpodaffinity/scoring.go

@@ -131,7 +131,7 @@ func (pl *InterPodAffinity) PreScore(
 ) *framework.Status {
 	if len(nodes) == 0 {
 		// No nodes to score.
-		return nil
+		return framework.NewStatus(framework.Skip)
 	}
 
 	if pl.sharedLister == nil {
@@ -145,10 +145,7 @@ func (pl *InterPodAffinity) PreScore(
 	// Optionally ignore calculating preferences of existing pods' affinity rules
 	// if the incoming pod has no inter-pod affinities.
 	if pl.args.IgnorePreferredTermsOfExistingPods && !hasPreferredAffinityConstraints && !hasPreferredAntiAffinityConstraints {
-		cycleState.Write(preScoreStateKey, &preScoreState{
+		return framework.NewStatus(framework.Skip)
-			topologyScore: make(map[string]map[string]int64),
-		})
-		return nil
 	}
 
 	// Unless the pod being scheduled has preferred affinity terms, we only
@@ -213,6 +210,10 @@ func (pl *InterPodAffinity) PreScore(
 	}
 	pl.parallelizer.Until(pCtx, len(allNodes), processNode, pl.Name())
 
+	if index == -1 {
+		return framework.NewStatus(framework.Skip)
+	}
+
 	for i := 0; i <= int(index); i++ {
 		state.topologyScore.append(topoScores[i])
 	}

pkg/scheduler/framework/plugins/interpodaffinity/scoring_test.go

@@ -22,6 +22,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -385,7 +386,7 @@ func TestPreferredAffinity(t *testing.T) {
 				{ObjectMeta: metav1.ObjectMeta{Name: "node2", Labels: labelRgIndia}},
 				{ObjectMeta: metav1.ObjectMeta{Name: "node3", Labels: labelAzAz1}},
 			},
-			expectedList: []framework.NodeScore{{Name: "node1", Score: 0}, {Name: "node2", Score: 0}, {Name: "node3", Score: 0}},
+			wantStatus: framework.NewStatus(framework.Skip),
 		},
 		// the node(node1) that have the label {"region": "China"} (match the topology key) and that have existing pods that match the labelSelector get high score
 		// the node(node3) that don't have the label {"region": "whatever the value is"} (mismatch the topology key) but that have existing pods that match the labelSelector get low score
@@ -749,6 +750,7 @@ func TestPreferredAffinity(t *testing.T) {
 				{ObjectMeta: metav1.ObjectMeta{Name: "node2", Labels: labelRgIndia}},
 			},
 			expectedList:                       []framework.NodeScore{{Name: "node1", Score: 0}, {Name: "node2", Score: 0}},
+			wantStatus:                         framework.NewStatus(framework.Skip),
 			ignorePreferredTermsOfExistingPods: true,
 		},
 		{
@@ -765,6 +767,13 @@ func TestPreferredAffinity(t *testing.T) {
 			expectedList:                       []framework.NodeScore{{Name: "node1", Score: 0}, {Name: "node2", Score: framework.MaxNodeScore}},
 			ignorePreferredTermsOfExistingPods: false,
 		},
+		{
+			name:       "No nodes to score",
+			pod:        &v1.Pod{Spec: v1.PodSpec{NodeName: ""}, ObjectMeta: metav1.ObjectMeta{Labels: podLabelSecurityS2}},
+			pods:       []*v1.Pod{},
+			nodes:      []*v1.Node{},
+			wantStatus: framework.NewStatus(framework.Skip),
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
@@ -773,31 +782,36 @@ func TestPreferredAffinity(t *testing.T) {
 			state := framework.NewCycleState()
 			p := plugintesting.SetupPluginWithInformers(ctx, t, New, &config.InterPodAffinityArgs{HardPodAffinityWeight: 1, IgnorePreferredTermsOfExistingPods: test.ignorePreferredTermsOfExistingPods}, cache.NewSnapshot(test.pods, test.nodes), namespaces)
 			status := p.(framework.PreScorePlugin).PreScore(ctx, state, test.pod, test.nodes)
+
 			if !status.IsSuccess() {
+				if status.Code() != test.wantStatus.Code() {
+					t.Errorf("InterPodAffinity#PreScore() returned unexpected status.Code got: %v, want: %v", status.Code(), test.wantStatus.Code())
+				}
+
 				if !strings.Contains(status.Message(), test.wantStatus.Message()) {
-					t.Errorf("unexpected error: %v", status)
+					t.Errorf("InterPodAffinity#PreScore() returned unexpected status.Message got: %v, want: %v", status.Message(), test.wantStatus.Message())
-				}
-			} else {
-				var gotList framework.NodeScoreList
-				for _, n := range test.nodes {
-					nodeName := n.ObjectMeta.Name
-					score, status := p.(framework.ScorePlugin).Score(ctx, state, test.pod, nodeName)
-					if !status.IsSuccess() {
-						t.Errorf("unexpected error: %v", status)
-					}
-					gotList = append(gotList, framework.NodeScore{Name: nodeName, Score: score})
-				}
-
-				status = p.(framework.ScorePlugin).ScoreExtensions().NormalizeScore(ctx, state, test.pod, gotList)
-				if !status.IsSuccess() {
-					t.Errorf("unexpected error: %v", status)
-				}
-
-				if !reflect.DeepEqual(test.expectedList, gotList) {
-					t.Errorf("expected:\n\t%+v,\ngot:\n\t%+v", test.expectedList, gotList)
 				}
+				return
 			}
 
+			var gotList framework.NodeScoreList
+			for _, n := range test.nodes {
+				nodeName := n.ObjectMeta.Name
+				score, status := p.(framework.ScorePlugin).Score(ctx, state, test.pod, nodeName)
+				if !status.IsSuccess() {
+					t.Errorf("unexpected error from Score: %v", status)
+				}
+				gotList = append(gotList, framework.NodeScore{Name: nodeName, Score: score})
+			}
+
+			status = p.(framework.ScorePlugin).ScoreExtensions().NormalizeScore(ctx, state, test.pod, gotList)
+			if !status.IsSuccess() {
+				t.Errorf("unexpected error from NormalizeScore: %v", status)
+			}
+
+			if diff := cmp.Diff(test.expectedList, gotList); diff != "" {
+				t.Errorf("node score list doesn't match (-want,+got): \n %s", diff)
+			}
 		})
 	}
 }
@@ -850,6 +864,7 @@ func TestPreferredAffinityWithHardPodAffinitySymmetricWeight(t *testing.T) {
 		hardPodAffinityWeight int32
 		expectedList          framework.NodeScoreList
 		name                  string
+		wantStatus            *framework.Status
 	}{
 		{
 			name: "with default weight",
@@ -879,7 +894,7 @@ func TestPreferredAffinityWithHardPodAffinitySymmetricWeight(t *testing.T) {
 				{ObjectMeta: metav1.ObjectMeta{Name: "node3", Labels: labelAzAz1}},
 			},
 			hardPodAffinityWeight: 0,
-			expectedList:          []framework.NodeScore{{Name: "node1", Score: 0}, {Name: "node2", Score: 0}, {Name: "node3", Score: 0}},
+			wantStatus:            framework.NewStatus(framework.Skip),
 		},
 		{
 			name: "with no matching namespace",
@@ -894,7 +909,7 @@ func TestPreferredAffinityWithHardPodAffinitySymmetricWeight(t *testing.T) {
 				{ObjectMeta: metav1.ObjectMeta{Name: "node3", Labels: labelAzAz1}},
 			},
 			hardPodAffinityWeight: v1.DefaultHardPodAffinitySymmetricWeight,
-			expectedList:          []framework.NodeScore{{Name: "node1", Score: 0}, {Name: "node2", Score: 0}, {Name: "node3", Score: 0}},
+			wantStatus:            framework.NewStatus(framework.Skip),
 		},
 		{
 			name: "with matching NamespaceSelector",
@@ -934,9 +949,13 @@ func TestPreferredAffinityWithHardPodAffinitySymmetricWeight(t *testing.T) {
 			state := framework.NewCycleState()
 			p := plugintesting.SetupPluginWithInformers(ctx, t, New, &config.InterPodAffinityArgs{HardPodAffinityWeight: test.hardPodAffinityWeight}, cache.NewSnapshot(test.pods, test.nodes), namespaces)
 			status := p.(framework.PreScorePlugin).PreScore(ctx, state, test.pod, test.nodes)
-			if !status.IsSuccess() {
+			if !test.wantStatus.Equal(status) {
-				t.Errorf("unexpected error: %v", status)
+				t.Errorf("InterPodAffinity#PreScore() returned unexpected status.Code got: %v, want: %v", status.Code(), test.wantStatus.Code())
 			}
+			if !status.IsSuccess() {
+				return
+			}
+
 			var gotList framework.NodeScoreList
 			for _, n := range test.nodes {
 				nodeName := n.ObjectMeta.Name