Add defaultingType to PodTopologySpreadArgs

Change-Id: Ibf6a4fdb39a31fe9deed68de7e7cb24a9bf9d06a

pkg/scheduler/apis/config/scheme/BUILD

@@ -34,7 +34,6 @@ go_test(
     srcs = ["scheme_test.go"],
     embed = [":go_default_library"],
     deps = [
-        "//pkg/features:go_default_library",
         "//pkg/scheduler/apis/config:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",
         "//staging/src/k8s.io/apimachinery/pkg/runtime:go_default_library",

pkg/scheduler/apis/config/scheme/scheme_test.go

@@ -28,12 +28,13 @@ import (
 	"k8s.io/component-base/featuregate"
 	featuregatetesting "k8s.io/component-base/featuregate/testing"
 	"k8s.io/kube-scheduler/config/v1beta1"
-	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/pkg/scheduler/apis/config"
 	"k8s.io/utils/pointer"
 	"sigs.k8s.io/yaml"
 )
 
+// TestCodecsDecodePluginConfig tests that embedded plugin args get decoded
+// into their appropriate internal types and defaults are applied.
 func TestCodecsDecodePluginConfig(t *testing.T) {
 	testCases := []struct {
 		name         string
@@ -116,6 +117,7 @@ profiles:
 								DefaultConstraints: []corev1.TopologySpreadConstraint{
 									{MaxSkew: 1, TopologyKey: "zone", WhenUnsatisfiable: corev1.ScheduleAnyway},
 								},
+								DefaultingType: config.ListDefaulting,
 							},
 						},
 						{
@@ -297,71 +299,10 @@ profiles:
 								BindTimeoutSeconds: 600,
 							},
 						},
-						{
-							Name: "PodTopologySpread",
-							Args: &config.PodTopologySpreadArgs{},
-						},
-					},
-				},
-			},
-		},
-		{
-			name: "empty PodTopologySpread, feature DefaultPodTopologySpread enabled",
-			data: []byte(`
-apiVersion: kubescheduler.config.k8s.io/v1beta1
-kind: KubeSchedulerConfiguration
-profiles:
-- pluginConfig:
-  - name: PodTopologySpread
-    args:
-      defaultConstraints:
-`),
-			feature: features.DefaultPodTopologySpread,
-			wantProfiles: []config.KubeSchedulerProfile{
-				{
-					SchedulerName: "default-scheduler",
-					PluginConfig: []config.PluginConfig{
 						{
 							Name: "PodTopologySpread",
 							Args: &config.PodTopologySpreadArgs{
-								DefaultConstraints: []corev1.TopologySpreadConstraint{
-									{
-										MaxSkew:           3,
-										TopologyKey:       corev1.LabelHostname,
-										WhenUnsatisfiable: corev1.ScheduleAnyway,
-									},
-									{
-										MaxSkew:           5,
-										TopologyKey:       corev1.LabelZoneFailureDomainStable,
-										WhenUnsatisfiable: corev1.ScheduleAnyway,
-									},
-								},
-							},
-						},
-					},
-				},
-			},
-		},
-		{
-			name: "empty array PodTopologySpread, feature DefaultPodTopologySpread enabled",
-			data: []byte(`
-apiVersion: kubescheduler.config.k8s.io/v1beta1
-kind: KubeSchedulerConfiguration
-profiles:
-- pluginConfig:
-  - name: PodTopologySpread
-    args:
-      defaultConstraints: []
-`),
-			feature: features.DefaultPodTopologySpread,
-			wantProfiles: []config.KubeSchedulerProfile{
-				{
-					SchedulerName: "default-scheduler",
-					PluginConfig: []config.PluginConfig{
-						{
-							Name: "PodTopologySpread",
-							Args: &config.PodTopologySpreadArgs{
-								DefaultConstraints: []corev1.TopologySpreadConstraint{},
+								DefaultingType: config.ListDefaulting,
 							},
 						},
 					},
@@ -514,7 +455,6 @@ profiles:
     name: NodeResourcesLeastAllocated
   - args:
       apiVersion: kubescheduler.config.k8s.io/v1beta1
-      defaultConstraints: []
       kind: PodTopologySpreadArgs
     name: PodTopologySpread
   - args:
@@ -605,7 +545,6 @@ profiles:
     name: VolumeBinding
   - args:
       apiVersion: kubescheduler.config.k8s.io/v1beta1
-      defaultConstraints: null
       kind: PodTopologySpreadArgs
     name: PodTopologySpread
   - args:

pkg/scheduler/apis/config/testing/compatibility_test.go

@@ -1622,6 +1622,7 @@ func TestPluginsConfigurationCompatibility(t *testing.T) {
 								WhenUnsatisfiable: v1.ScheduleAnyway,
 							},
 						},
+						DefaultingType: config.ListDefaulting,
 					},
 				},
 				{
@@ -1686,6 +1687,7 @@ func TestPluginsConfigurationCompatibility(t *testing.T) {
 								WhenUnsatisfiable: v1.ScheduleAnyway,
 							},
 						},
+						DefaultingType: config.ListDefaulting,
 					},
 				},
 				{

pkg/scheduler/apis/config/types_pluginargs.go

@@ -64,6 +64,17 @@ type NodeResourcesFitArgs struct {
 	IgnoredResourceGroups []string
 }
 
+// PodTopologySpreadConstraintsDefaulting defines how to set default constraints
+// for the PodTopologySpread plugin.
+type PodTopologySpreadConstraintsDefaulting string
+
+const (
+	// SystemDefaulting instructs to use the kubernetes defined default.
+	SystemDefaulting PodTopologySpreadConstraintsDefaulting = "System"
+	// ListDefaulting instructs to use the config provided default.
+	ListDefaulting PodTopologySpreadConstraintsDefaulting = "List"
+)
+
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // PodTopologySpreadArgs holds arguments used to configure the PodTopologySpread plugin.
@@ -71,12 +82,24 @@ type PodTopologySpreadArgs struct {
 	metav1.TypeMeta
 
 	// DefaultConstraints defines topology spread constraints to be applied to
-	// pods that don't define any in `pod.spec.topologySpreadConstraints`.
-	// `topologySpreadConstraint.labelSelectors` must be empty, as they are
-	// deduced the pods' membership to Services, Replication Controllers, Replica
-	// Sets or Stateful Sets.
-	// Empty by default.
+	// Pods that don't define any in `pod.spec.topologySpreadConstraints`.
+	// `.defaultConstraints[*].labelSelectors` must be empty, as they are
+	// deduced from the Pod's membership to Services, ReplicationControllers,
+	// ReplicaSets or StatefulSets.
+	// When not empty, .defaultingType must be "List".
 	DefaultConstraints []v1.TopologySpreadConstraint
+
+	// DefaultingType determines how .defaultConstraints are deduced. Can be one
+	// of "System" or "List".
+	//
+	// - "System": Use kubernetes defined constraints that spread Pods among
+	//   Nodes and Zones.
+	// - "List": Use constraints defined in .defaultConstraints.
+	//
+	// Defaults to "List" if feature gate DefaultPodTopologySpread is disabled
+	// and to "System" if enabled.
+	// +optional
+	DefaultingType PodTopologySpreadConstraintsDefaulting
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object

pkg/scheduler/apis/config/v1beta1/defaults.go

@@ -195,23 +195,18 @@ func SetDefaults_VolumeBindingArgs(obj *v1beta1.VolumeBindingArgs) {
 }
 
 func SetDefaults_PodTopologySpreadArgs(obj *v1beta1.PodTopologySpreadArgs) {
-	if !feature.DefaultFeatureGate.Enabled(features.DefaultPodTopologySpread) {
-		// When feature is disabled, the default spreading is done by legacy
-		// SelectorSpread plugin.
+	if feature.DefaultFeatureGate.Enabled(features.DefaultPodTopologySpread) {
+		if obj.DefaultingType == "" {
+			// TODO(#94008): Always default to System in v1beta2.
+			if len(obj.DefaultConstraints) != 0 {
+				obj.DefaultingType = v1beta1.ListDefaulting
+			} else {
+				obj.DefaultingType = v1beta1.SystemDefaulting
+			}
+		}
 		return
 	}
-	if obj.DefaultConstraints == nil {
-		obj.DefaultConstraints = []corev1.TopologySpreadConstraint{
-			{
-				TopologyKey:       corev1.LabelHostname,
-				WhenUnsatisfiable: corev1.ScheduleAnyway,
-				MaxSkew:           3,
-			},
-			{
-				TopologyKey:       corev1.LabelZoneFailureDomainStable,
-				WhenUnsatisfiable: corev1.ScheduleAnyway,
-				MaxSkew:           5,
-			},
-		}
+	if obj.DefaultingType == "" {
+		obj.DefaultingType = v1beta1.ListDefaulting
 	}
 }

pkg/scheduler/apis/config/v1beta1/defaults_test.go

@@ -367,7 +367,9 @@ func TestPluginArgsDefaults(t *testing.T) {
 		{
 			name: "PodTopologySpreadArgs resources empty",
 			in:   &v1beta1.PodTopologySpreadArgs{},
-			want: &v1beta1.PodTopologySpreadArgs{},
+			want: &v1beta1.PodTopologySpreadArgs{
+				DefaultingType: v1beta1.ListDefaulting,
+			},
 		},
 		{
 			name: "PodTopologySpreadArgs resources with value",
@@ -388,12 +390,29 @@ func TestPluginArgsDefaults(t *testing.T) {
 						MaxSkew:           2,
 					},
 				},
+				DefaultingType: v1beta1.ListDefaulting,
 			},
 		},
 		{
-			name:    "PodTopologySpreadArgs resources empty, DefaultPodTopologySpread feature enabled",
+			name:    "PodTopologySpreadArgs empty, DefaultPodTopologySpread feature enabled",
 			feature: features.DefaultPodTopologySpread,
 			in:      &v1beta1.PodTopologySpreadArgs{},
+			want: &v1beta1.PodTopologySpreadArgs{
+				DefaultingType: v1beta1.SystemDefaulting,
+			},
+		},
+		{
+			name:    "PodTopologySpreadArgs with constraints, DefaultPodTopologySpread feature enabled",
+			feature: features.DefaultPodTopologySpread,
+			in: &v1beta1.PodTopologySpreadArgs{
+				DefaultConstraints: []v1.TopologySpreadConstraint{
+					{
+						TopologyKey:       v1.LabelHostname,
+						WhenUnsatisfiable: v1.ScheduleAnyway,
+						MaxSkew:           3,
+					},
+				},
+			},
 			want: &v1beta1.PodTopologySpreadArgs{
 				DefaultConstraints: []v1.TopologySpreadConstraint{
 					{
@@ -401,22 +420,9 @@ func TestPluginArgsDefaults(t *testing.T) {
 						WhenUnsatisfiable: v1.ScheduleAnyway,
 						MaxSkew:           3,
 					},
-					{
-						TopologyKey:       v1.LabelZoneFailureDomainStable,
-						WhenUnsatisfiable: v1.ScheduleAnyway,
-						MaxSkew:           5,
-					},
 				},
-			},
-		},
-		{
-			name:    "PodTopologySpreadArgs empty array, DefaultPodTopologySpread feature enabled",
-			feature: features.DefaultPodTopologySpread,
-			in: &v1beta1.PodTopologySpreadArgs{
-				DefaultConstraints: []v1.TopologySpreadConstraint{},
-			},
-			want: &v1beta1.PodTopologySpreadArgs{
-				DefaultConstraints: []v1.TopologySpreadConstraint{},
+				// TODO(#94008): Make SystemDefaulting in v1beta2.
+				DefaultingType: v1beta1.ListDefaulting,
 			},
 		},
 	}

pkg/scheduler/apis/config/v1beta1/zz_generated.conversion.go

@@ -854,6 +854,7 @@ func Convert_config_Plugins_To_v1beta1_Plugins(in *config.Plugins, out *v1beta1.
 
 func autoConvert_v1beta1_PodTopologySpreadArgs_To_config_PodTopologySpreadArgs(in *v1beta1.PodTopologySpreadArgs, out *config.PodTopologySpreadArgs, s conversion.Scope) error {
 	out.DefaultConstraints = *(*[]corev1.TopologySpreadConstraint)(unsafe.Pointer(&in.DefaultConstraints))
+	out.DefaultingType = config.PodTopologySpreadConstraintsDefaulting(in.DefaultingType)
 	return nil
 }
 
@@ -864,6 +865,7 @@ func Convert_v1beta1_PodTopologySpreadArgs_To_config_PodTopologySpreadArgs(in *v
 
 func autoConvert_config_PodTopologySpreadArgs_To_v1beta1_PodTopologySpreadArgs(in *config.PodTopologySpreadArgs, out *v1beta1.PodTopologySpreadArgs, s conversion.Scope) error {
 	out.DefaultConstraints = *(*[]corev1.TopologySpreadConstraint)(unsafe.Pointer(&in.DefaultConstraints))
+	out.DefaultingType = v1beta1.PodTopologySpreadConstraintsDefaulting(in.DefaultingType)
 	return nil
 }
 

pkg/scheduler/apis/config/validation/validation_pluginargs.go

@@ -75,6 +75,9 @@ func validateNoConflict(presentLabels []string, absentLabels []string) error {
 // with an additional check for .labelSelector to be nil.
 func ValidatePodTopologySpreadArgs(args *config.PodTopologySpreadArgs) error {
 	var allErrs field.ErrorList
+	if err := validateDefaultingType(field.NewPath("defaultingType"), args.DefaultingType, args.DefaultConstraints); err != nil {
+		allErrs = append(allErrs, err)
+	}
 	path := field.NewPath("defaultConstraints")
 
 	for i, c := range args.DefaultConstraints {
@@ -101,6 +104,16 @@ func ValidatePodTopologySpreadArgs(args *config.PodTopologySpreadArgs) error {
 	return allErrs.ToAggregate()
 }
 
+func validateDefaultingType(p *field.Path, v config.PodTopologySpreadConstraintsDefaulting, constraints []v1.TopologySpreadConstraint) *field.Error {
+	if v != config.SystemDefaulting && v != config.ListDefaulting {
+		return field.Invalid(p, v, fmt.Sprintf("must be one of {%q, %q}", config.SystemDefaulting, config.ListDefaulting))
+	}
+	if v == config.SystemDefaulting && len(constraints) > 0 {
+		return field.Invalid(p, v, "when .defaultConstraints are not empty")
+	}
+	return nil
+}
+
 func validateTopologyKey(p *field.Path, v string) field.ErrorList {
 	var allErrs field.ErrorList
 	if len(v) == 0 {

pkg/scheduler/apis/config/validation/validation_pluginargs_test.go

@@ -112,6 +112,7 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						WhenUnsatisfiable: v1.ScheduleAnyway,
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 		},
 		"maxSkew less than zero": {
@@ -123,6 +124,7 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						WhenUnsatisfiable: v1.DoNotSchedule,
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 			wantErr: `defaultConstraints[0].maxSkew: Invalid value: -1: must be greater than zero`,
 		},
@@ -135,6 +137,7 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						WhenUnsatisfiable: v1.DoNotSchedule,
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 			wantErr: `defaultConstraints[0].topologyKey: Required value: can not be empty`,
 		},
@@ -147,6 +150,7 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						WhenUnsatisfiable: "",
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 			wantErr: `defaultConstraints[0].whenUnsatisfiable: Required value: can not be empty`,
 		},
@@ -159,6 +163,7 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						WhenUnsatisfiable: "unknown action",
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 			wantErr: `defaultConstraints[0].whenUnsatisfiable: Unsupported value: "unknown action": supported values: "DoNotSchedule", "ScheduleAnyway"`,
 		},
@@ -176,6 +181,7 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						WhenUnsatisfiable: v1.DoNotSchedule,
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 			wantErr: `defaultConstraints[1]: Duplicate value: "{node, DoNotSchedule}"`,
 		},
@@ -193,9 +199,33 @@ func TestValidatePodTopologySpreadArgs(t *testing.T) {
 						},
 					},
 				},
+				DefaultingType: config.ListDefaulting,
 			},
 			wantErr: `defaultConstraints[0].labelSelector: Forbidden: constraint must not define a selector, as they deduced for each pod`,
 		},
+		"list default constraints, no constraints": {
+			args: &config.PodTopologySpreadArgs{
+				DefaultingType: config.ListDefaulting,
+			},
+		},
+		"system default constraints": {
+			args: &config.PodTopologySpreadArgs{
+				DefaultingType: config.SystemDefaulting,
+			},
+		},
+		"system default constraints, but has constraints": {
+			args: &config.PodTopologySpreadArgs{
+				DefaultConstraints: []v1.TopologySpreadConstraint{
+					{
+						MaxSkew:           1,
+						TopologyKey:       "key",
+						WhenUnsatisfiable: v1.DoNotSchedule,
+					},
+				},
+				DefaultingType: config.SystemDefaulting,
+			},
+			wantErr: `defaultingType: Invalid value: "System": when .defaultConstraints are not empty`,
+		},
 	}
 
 	for name, tc := range cases {

pkg/scheduler/framework/plugins/podtopologyspread/BUILD

@@ -37,6 +37,7 @@ go_test(
     embed = [":go_default_library"],
     deps = [
         "//pkg/scheduler/apis/config:go_default_library",
+        "//pkg/scheduler/framework/runtime:go_default_library",
         "//pkg/scheduler/framework/v1alpha1:go_default_library",
         "//pkg/scheduler/internal/cache:go_default_library",
         "//pkg/scheduler/internal/parallelize:go_default_library",

pkg/scheduler/framework/plugins/podtopologyspread/common.go

@@ -38,11 +38,11 @@ type topologySpreadConstraint struct {
 	Selector    labels.Selector
 }
 
-// defaultConstraints builds the constraints for a pod using
+// buildDefaultConstraints builds the constraints for a pod using
 // .DefaultConstraints and the selectors from the services, replication
 // controllers, replica sets and stateful sets that match the pod.
-func (pl *PodTopologySpread) defaultConstraints(p *v1.Pod, action v1.UnsatisfiableConstraintAction) ([]topologySpreadConstraint, error) {
-	constraints, err := filterTopologySpreadConstraints(pl.args.DefaultConstraints, action)
+func (pl *PodTopologySpread) buildDefaultConstraints(p *v1.Pod, action v1.UnsatisfiableConstraintAction) ([]topologySpreadConstraint, error) {
+	constraints, err := filterTopologySpreadConstraints(pl.defaultConstraints, action)
 	if err != nil || len(constraints) == 0 {
 		return nil, err
 	}

pkg/scheduler/framework/plugins/podtopologyspread/filtering.go

@@ -209,7 +209,7 @@ func (pl *PodTopologySpread) calPreFilterState(pod *v1.Pod) (*preFilterState, er
 			return nil, fmt.Errorf("obtaining pod's hard topology spread constraints: %v", err)
 		}
 	} else {
-		constraints, err = pl.defaultConstraints(pod, v1.DoNotSchedule)
+		constraints, err = pl.buildDefaultConstraints(pod, v1.DoNotSchedule)
 		if err != nil {
 			return nil, fmt.Errorf("setting default hard topology spread constraints: %v", err)
 		}

pkg/scheduler/framework/plugins/podtopologyspread/filtering_test.go

@@ -29,7 +29,6 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes/fake"
-	"k8s.io/kubernetes/pkg/scheduler/apis/config"
 	framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
 	"k8s.io/kubernetes/pkg/scheduler/internal/cache"
 	"k8s.io/kubernetes/pkg/scheduler/internal/parallelize"
@@ -518,10 +517,8 @@ func TestPreFilterState(t *testing.T) {
 			ctx := context.Background()
 			informerFactory := informers.NewSharedInformerFactory(fake.NewSimpleClientset(tt.objs...), 0)
 			pl := PodTopologySpread{
-				sharedLister: cache.NewSnapshot(tt.existingPods, tt.nodes),
-				args: config.PodTopologySpreadArgs{
-					DefaultConstraints: tt.defaultConstraints,
-				},
+				sharedLister:       cache.NewSnapshot(tt.existingPods, tt.nodes),
+				defaultConstraints: tt.defaultConstraints,
 			}
 			pl.setListers(informerFactory)
 			informerFactory.Start(ctx.Done())

pkg/scheduler/framework/plugins/podtopologyspread/plugin.go

@@ -19,6 +19,7 @@ package podtopologyspread
 import (
 	"fmt"
 
+	v1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/client-go/informers"
 	appslisters "k8s.io/client-go/listers/apps/v1"
@@ -35,14 +36,27 @@ const (
 	ErrReasonNodeLabelNotMatch = ErrReasonConstraintsNotMatch + " (missing required label)"
 )
 
+var systemDefaultConstraints = []v1.TopologySpreadConstraint{
+	{
+		TopologyKey:       v1.LabelHostname,
+		WhenUnsatisfiable: v1.ScheduleAnyway,
+		MaxSkew:           3,
+	},
+	{
+		TopologyKey:       v1.LabelZoneFailureDomainStable,
+		WhenUnsatisfiable: v1.ScheduleAnyway,
+		MaxSkew:           5,
+	},
+}
+
 // PodTopologySpread is a plugin that ensures pod's topologySpreadConstraints is satisfied.
 type PodTopologySpread struct {
-	args             config.PodTopologySpreadArgs
-	sharedLister     framework.SharedLister
-	services         corelisters.ServiceLister
-	replicationCtrls corelisters.ReplicationControllerLister
-	replicaSets      appslisters.ReplicaSetLister
-	statefulSets     appslisters.StatefulSetLister
+	defaultConstraints []v1.TopologySpreadConstraint
+	sharedLister       framework.SharedLister
+	services           corelisters.ServiceLister
+	replicationCtrls   corelisters.ReplicationControllerLister
+	replicaSets        appslisters.ReplicaSetLister
+	statefulSets       appslisters.StatefulSetLister
 }
 
 var _ framework.PreFilterPlugin = &PodTopologySpread{}
@@ -73,10 +87,13 @@ func New(plArgs runtime.Object, h framework.FrameworkHandle) (framework.Plugin,
 		return nil, err
 	}
 	pl := &PodTopologySpread{
-		sharedLister: h.SnapshotSharedLister(),
-		args:         args,
+		sharedLister:       h.SnapshotSharedLister(),
+		defaultConstraints: args.DefaultConstraints,
 	}
-	if len(pl.args.DefaultConstraints) != 0 {
+	if args.DefaultingType == config.SystemDefaulting {
+		pl.defaultConstraints = systemDefaultConstraints
+	}
+	if len(pl.defaultConstraints) != 0 {
 		if h.SharedInformerFactory() == nil {
 			return nil, fmt.Errorf("SharedInformerFactory is nil")
 		}

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

@@ -64,7 +64,7 @@ func (pl *PodTopologySpread) initPreScoreState(s *preScoreState, pod *v1.Pod, fi
 			return fmt.Errorf("obtaining pod's soft topology spread constraints: %v", err)
 		}
 	} else {
-		s.Constraints, err = pl.defaultConstraints(pod, v1.ScheduleAnyway)
+		s.Constraints, err = pl.buildDefaultConstraints(pod, v1.ScheduleAnyway)
 		if err != nil {
 			return fmt.Errorf("setting default soft topology spread constraints: %v", err)
 		}

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

@@ -28,6 +28,7 @@ import (
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes/fake"
 	"k8s.io/kubernetes/pkg/scheduler/apis/config"
+	frameworkruntime "k8s.io/kubernetes/pkg/scheduler/framework/runtime"
 	framework "k8s.io/kubernetes/pkg/scheduler/framework/v1alpha1"
 	"k8s.io/kubernetes/pkg/scheduler/internal/cache"
 	"k8s.io/kubernetes/pkg/scheduler/internal/parallelize"
@@ -37,12 +38,12 @@ import (
 
 func TestPreScoreStateEmptyNodes(t *testing.T) {
 	tests := []struct {
-		name               string
-		pod                *v1.Pod
-		nodes              []*v1.Node
-		objs               []runtime.Object
-		defaultConstraints []v1.TopologySpreadConstraint
-		want               *preScoreState
+		name   string
+		pod    *v1.Pod
+		nodes  []*v1.Node
+		objs   []runtime.Object
+		config config.PodTopologySpreadArgs
+		want   *preScoreState
 	}{
 		{
 			name: "normal case",
@@ -55,6 +56,9 @@ func TestPreScoreStateEmptyNodes(t *testing.T) {
 				st.MakeNode().Name("node-b").Label("zone", "zone1").Label(v1.LabelHostname, "node-b").Obj(),
 				st.MakeNode().Name("node-x").Label("zone", "zone2").Label(v1.LabelHostname, "node-x").Obj(),
 			},
+			config: config.PodTopologySpreadArgs{
+				DefaultingType: config.ListDefaulting,
+			},
 			want: &preScoreState{
 				Constraints: []topologySpreadConstraint{
 					{
@@ -87,6 +91,9 @@ func TestPreScoreStateEmptyNodes(t *testing.T) {
 				st.MakeNode().Name("node-b").Label("zone", "zone1").Label(v1.LabelHostname, "node-b").Obj(),
 				st.MakeNode().Name("node-x").Label(v1.LabelHostname, "node-x").Obj(),
 			},
+			config: config.PodTopologySpreadArgs{
+				DefaultingType: config.ListDefaulting,
+			},
 			want: &preScoreState{
 				Constraints: []topologySpreadConstraint{
 					{
@@ -107,13 +114,48 @@ func TestPreScoreStateEmptyNodes(t *testing.T) {
 				TopologyNormalizingWeight: []float64{topologyNormalizingWeight(1), topologyNormalizingWeight(2)},
 			},
 		},
+		{
+			name: "system defaults constraints and a replica set",
+			pod:  st.MakePod().Name("p").Label("foo", "tar").Label("baz", "sup").Obj(),
+			config: config.PodTopologySpreadArgs{
+				DefaultingType: config.SystemDefaulting,
+			},
+			nodes: []*v1.Node{
+				st.MakeNode().Name("node-a").Label(v1.LabelHostname, "node-a").Label(v1.LabelZoneFailureDomainStable, "mars").Obj(),
+			},
+			objs: []runtime.Object{
+				&appsv1.ReplicaSet{Spec: appsv1.ReplicaSetSpec{Selector: st.MakeLabelSelector().Exists("foo").Obj()}},
+			},
+			want: &preScoreState{
+				Constraints: []topologySpreadConstraint{
+					{
+						MaxSkew:     3,
+						TopologyKey: v1.LabelHostname,
+						Selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Exists("foo").Obj()),
+					},
+					{
+						MaxSkew:     5,
+						TopologyKey: v1.LabelZoneFailureDomainStable,
+						Selector:    mustConvertLabelSelectorAsSelector(t, st.MakeLabelSelector().Exists("foo").Obj()),
+					},
+				},
+				IgnoredNodes: sets.NewString(),
+				TopologyPairToPodCounts: map[topologyPair]*int64{
+					{key: v1.LabelZoneFailureDomainStable, value: "mars"}: pointer.Int64Ptr(0),
+				},
+				TopologyNormalizingWeight: []float64{topologyNormalizingWeight(1), topologyNormalizingWeight(1)},
+			},
+		},
 		{
 			name: "defaults constraints and a replica set",
 			pod:  st.MakePod().Name("p").Label("foo", "tar").Label("baz", "sup").Obj(),
-			defaultConstraints: []v1.TopologySpreadConstraint{
-				{MaxSkew: 1, TopologyKey: v1.LabelHostname, WhenUnsatisfiable: v1.ScheduleAnyway},
-				{MaxSkew: 2, TopologyKey: "rack", WhenUnsatisfiable: v1.DoNotSchedule},
-				{MaxSkew: 2, TopologyKey: "planet", WhenUnsatisfiable: v1.ScheduleAnyway},
+			config: config.PodTopologySpreadArgs{
+				DefaultConstraints: []v1.TopologySpreadConstraint{
+					{MaxSkew: 1, TopologyKey: v1.LabelHostname, WhenUnsatisfiable: v1.ScheduleAnyway},
+					{MaxSkew: 2, TopologyKey: "rack", WhenUnsatisfiable: v1.DoNotSchedule},
+					{MaxSkew: 2, TopologyKey: "planet", WhenUnsatisfiable: v1.ScheduleAnyway},
+				},
+				DefaultingType: config.ListDefaulting,
 			},
 			nodes: []*v1.Node{
 				st.MakeNode().Name("node-a").Label("rack", "rack1").Label(v1.LabelHostname, "node-a").Label("planet", "mars").Obj(),
@@ -144,8 +186,11 @@ func TestPreScoreStateEmptyNodes(t *testing.T) {
 		{
 			name: "defaults constraints and a replica set that doesn't match",
 			pod:  st.MakePod().Name("p").Label("foo", "bar").Label("baz", "sup").Obj(),
-			defaultConstraints: []v1.TopologySpreadConstraint{
-				{MaxSkew: 2, TopologyKey: "planet", WhenUnsatisfiable: v1.ScheduleAnyway},
+			config: config.PodTopologySpreadArgs{
+				DefaultConstraints: []v1.TopologySpreadConstraint{
+					{MaxSkew: 2, TopologyKey: "planet", WhenUnsatisfiable: v1.ScheduleAnyway},
+				},
+				DefaultingType: config.ListDefaulting,
 			},
 			nodes: []*v1.Node{
 				st.MakeNode().Name("node-a").Label("planet", "mars").Obj(),
@@ -162,8 +207,11 @@ func TestPreScoreStateEmptyNodes(t *testing.T) {
 			pod: st.MakePod().Name("p").Label("foo", "bar").Label("baz", "sup").
 				SpreadConstraint(1, "zone", v1.DoNotSchedule, st.MakeLabelSelector().Label("foo", "bar").Obj()).
 				SpreadConstraint(2, "planet", v1.ScheduleAnyway, st.MakeLabelSelector().Label("baz", "sup").Obj()).Obj(),
-			defaultConstraints: []v1.TopologySpreadConstraint{
-				{MaxSkew: 2, TopologyKey: "galaxy", WhenUnsatisfiable: v1.ScheduleAnyway},
+			config: config.PodTopologySpreadArgs{
+				DefaultConstraints: []v1.TopologySpreadConstraint{
+					{MaxSkew: 2, TopologyKey: "galaxy", WhenUnsatisfiable: v1.ScheduleAnyway},
+				},
+				DefaultingType: config.ListDefaulting,
 			},
 			nodes: []*v1.Node{
 				st.MakeNode().Name("node-a").Label("planet", "mars").Label("galaxy", "andromeda").Obj(),
@@ -191,17 +239,21 @@ func TestPreScoreStateEmptyNodes(t *testing.T) {
 		t.Run(tt.name, func(t *testing.T) {
 			ctx := context.Background()
 			informerFactory := informers.NewSharedInformerFactory(fake.NewSimpleClientset(tt.objs...), 0)
-			pl := PodTopologySpread{
-				sharedLister: cache.NewSnapshot(nil, tt.nodes),
-				args: config.PodTopologySpreadArgs{
-					DefaultConstraints: tt.defaultConstraints,
-				},
+			f, err := frameworkruntime.NewFramework(nil, nil, nil,
+				frameworkruntime.WithSnapshotSharedLister(cache.NewSnapshot(nil, tt.nodes)),
+				frameworkruntime.WithInformerFactory(informerFactory))
+			if err != nil {
+				t.Fatalf("Failed creating framework runtime: %v", err)
+			}
+			pl, err := New(&tt.config, f)
+			if err != nil {
+				t.Fatalf("Failed creating plugin: %v", err)
 			}
-			pl.setListers(informerFactory)
 			informerFactory.Start(ctx.Done())
 			informerFactory.WaitForCacheSync(ctx.Done())
+			p := pl.(*PodTopologySpread)
 			cs := framework.NewCycleState()
-			if s := pl.PreScore(context.Background(), cs, tt.pod, tt.nodes); !s.IsSuccess() {
+			if s := p.PreScore(context.Background(), cs, tt.pod, tt.nodes); !s.IsSuccess() {
 				t.Fatal(s.AsError())
 			}
 
@@ -765,24 +817,25 @@ func BenchmarkTestDefaultEvenPodsSpreadPriority(b *testing.B) {
 			existingPods, allNodes, filteredNodes := st.MakeNodesAndPodsForEvenPodsSpread(pod.Labels, tt.existingPodsNum, tt.allNodesNum, tt.allNodesNum)
 			state := framework.NewCycleState()
 			snapshot := cache.NewSnapshot(existingPods, allNodes)
-			p := &PodTopologySpread{
-				sharedLister: snapshot,
-				args: config.PodTopologySpreadArgs{
-					DefaultConstraints: []v1.TopologySpreadConstraint{
-						{MaxSkew: 1, TopologyKey: v1.LabelHostname, WhenUnsatisfiable: v1.ScheduleAnyway},
-						{MaxSkew: 1, TopologyKey: v1.LabelZoneFailureDomain, WhenUnsatisfiable: v1.ScheduleAnyway},
-					},
-				},
-			}
 			client := fake.NewSimpleClientset(
 				&v1.Service{Spec: v1.ServiceSpec{Selector: map[string]string{"foo": ""}}},
 			)
 			ctx := context.Background()
 			informerFactory := informers.NewSharedInformerFactory(client, 0)
-			p.setListers(informerFactory)
+			f, err := frameworkruntime.NewFramework(nil, nil, nil,
+				frameworkruntime.WithSnapshotSharedLister(snapshot),
+				frameworkruntime.WithInformerFactory(informerFactory))
+			if err != nil {
+				b.Fatalf("Failed creating framework runtime: %v", err)
+			}
+			pl, err := New(&config.PodTopologySpreadArgs{DefaultingType: config.SystemDefaulting}, f)
+			if err != nil {
+				b.Fatalf("Failed creating plugin: %v", err)
+			}
+			p := pl.(*PodTopologySpread)
+
 			informerFactory.Start(ctx.Done())
 			informerFactory.WaitForCacheSync(ctx.Done())
-
 			b.ResetTimer()
 
 			for i := 0; i < b.N; i++ {

pkg/scheduler/framework/runtime/framework_test.go

@@ -530,7 +530,9 @@ func TestNewFrameworkPluginDefaults(t *testing.T) {
 				"RequestedToCapacityRatio": &config.RequestedToCapacityRatioArgs{
 					Resources: []config.ResourceSpec{{Name: "cpu", Weight: 1}, {Name: "memory", Weight: 1}},
 				},
-				"PodTopologySpread": &config.PodTopologySpreadArgs{},
+				"PodTopologySpread": &config.PodTopologySpreadArgs{
+					DefaultingType: config.ListDefaulting,
+				},
 				"VolumeBinding": &config.VolumeBindingArgs{
 					BindTimeoutSeconds: 600,
 				},
@@ -590,7 +592,9 @@ func TestNewFrameworkPluginDefaults(t *testing.T) {
 				"NodeResourcesMostAllocated": &config.NodeResourcesMostAllocatedArgs{
 					Resources: []config.ResourceSpec{{Name: "resource", Weight: 3}},
 				},
-				"PodTopologySpread": &config.PodTopologySpreadArgs{},
+				"PodTopologySpread": &config.PodTopologySpreadArgs{
+					DefaultingType: config.ListDefaulting,
+				},
 				"RequestedToCapacityRatio": &config.RequestedToCapacityRatioArgs{
 					Resources: []config.ResourceSpec{{Name: "resource", Weight: 2}},
 				},

staging/src/k8s.io/kube-scheduler/config/v1beta1/types_pluginargs.go

@@ -70,6 +70,17 @@ type NodeResourcesFitArgs struct {
 	IgnoredResourceGroups []string `json:"ignoredResourceGroups,omitempty"`
 }
 
+// PodTopologySpreadConstraintsDefaulting defines how to set default constraints
+// for the PodTopologySpread plugin.
+type PodTopologySpreadConstraintsDefaulting string
+
+const (
+	// SystemDefaulting instructs to use the kubernetes defined default.
+	SystemDefaulting PodTopologySpreadConstraintsDefaulting = "System"
+	// ListDefaulting instructs to use the config provided default.
+	ListDefaulting PodTopologySpreadConstraintsDefaulting = "List"
+)
+
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // PodTopologySpreadArgs holds arguments used to configure the PodTopologySpread plugin.
@@ -77,14 +88,26 @@ type PodTopologySpreadArgs struct {
 	metav1.TypeMeta `json:",inline"`
 
 	// DefaultConstraints defines topology spread constraints to be applied to
-	// pods that don't define any in `pod.spec.topologySpreadConstraints`.
-	// `topologySpreadConstraint.labelSelectors` must be empty, as they are
-	// deduced the pods' membership to Services, Replication Controllers, Replica
-	// Sets or Stateful Sets.
-	// Empty by default.
+	// Pods that don't define any in `pod.spec.topologySpreadConstraints`.
+	// `.defaultConstraints[*].labelSelectors` must be empty, as they are
+	// deduced from the Pod's membership to Services, ReplicationControllers,
+	// ReplicaSets or StatefulSets.
+	// When not empty, .defaultingType must be "List".
 	// +optional
 	// +listType=atomic
-	DefaultConstraints []corev1.TopologySpreadConstraint `json:"defaultConstraints"`
+	DefaultConstraints []corev1.TopologySpreadConstraint `json:"defaultConstraints,omitempty"`
+
+	// DefaultingType determines how .defaultConstraints are deduced. Can be one
+	// of "System" or "List".
+	//
+	// - "System": Use kubernetes defined constraints that spread Pods among
+	//   Nodes and Zones.
+	// - "List": Use constraints defined in .defaultConstraints.
+	//
+	// Defaults to "List" if feature gate DefaultPodTopologySpread is disabled
+	// and to "System" if enabled.
+	// +optional
+	DefaultingType PodTopologySpreadConstraintsDefaulting `json:"defaultingType,omitempty"`
 }
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object