kubernetes · liggitt · Jul 28, 2025 · Jul 28, 2025 · Jul 28, 2025
diff --git a/pkg/controlplane/apiserver/config.go b/pkg/controlplane/apiserver/config.go
@@ -40,16 +40,17 @@ import (
 	"k8s.io/apiserver/pkg/server/egressselector"
 	"k8s.io/apiserver/pkg/server/filters"
 	serverstorage "k8s.io/apiserver/pkg/server/storage"
+	"k8s.io/apiserver/pkg/util/compatibility"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/apiserver/pkg/util/openapi"
 	utilpeerproxy "k8s.io/apiserver/pkg/util/peerproxy"
 	"k8s.io/client-go/dynamic"
 	clientgoinformers "k8s.io/client-go/informers"
 	clientgoclientset "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/util/keyutil"
+	basecompatibility "k8s.io/component-base/compatibility"
 	aggregatorapiserver "k8s.io/kube-aggregator/pkg/apiserver"
 	openapicommon "k8s.io/kube-openapi/pkg/common"
-
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 	controlplaneadmission "k8s.io/kubernetes/pkg/controlplane/apiserver/admission"
 	"k8s.io/kubernetes/pkg/controlplane/apiserver/options"
@@ -379,6 +380,7 @@ func CreateConfig(
 		clientgoExternalClient,
 		dynamicExternalClient,
 		utilfeature.DefaultFeatureGate,
+		compatibility.DefaultComponentGlobalsRegistry.EffectiveVersionFor(basecompatibility.DefaultKubeComponent),
 		append(genericInitializers, additionalInitializers...)...,
 	)
 	if err != nil {

diff --git a/pkg/features/kube_features.go b/pkg/features/kube_features.go
@@ -719,12 +719,6 @@ const (
 	// Denies pod admission if static pods reference other API objects.
 	PreventStaticPodAPIReferences featuregate.Feature = "PreventStaticPodAPIReferences"
 
-	// owner: @tssurya
-	// kep: https://kep.k8s.io/4559
-	//
-	// Enables probe host enforcement for Pod Security Standards.
-	ProbeHostPodSecurityStandards featuregate.Feature = "ProbeHostPodSecurityStandards"
-
 	// owner: @jessfraz
 	//
 	// Enables control over ProcMountType for containers.
@@ -1552,11 +1546,6 @@ var defaultVersionedKubernetesFeatureGates = map[featuregate.Feature]featuregate
 		{Version: version.MustParse("1.34"), Default: true, PreRelease: featuregate.Beta},
 	},
 
-	// Policy is GA in first release, this gate only exists to disable the enforcement when emulating older minors
-	ProbeHostPodSecurityStandards: {
-		{Version: version.MustParse("1.34"), Default: true, PreRelease: featuregate.GA, LockToDefault: true},
-	},
-
 	ProcMountType: {
 		{Version: version.MustParse("1.12"), Default: false, PreRelease: featuregate.Alpha},
 		{Version: version.MustParse("1.31"), Default: false, PreRelease: featuregate.Beta},

diff --git a/pkg/kubeapiserver/options/admission.go b/pkg/kubeapiserver/options/admission.go
@@ -21,6 +21,7 @@ import (
 	"strings"
 
 	"github.com/spf13/pflag"
+
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/kubernetes"
 
@@ -29,6 +30,7 @@ import (
 	"k8s.io/apiserver/pkg/server"
 	genericoptions "k8s.io/apiserver/pkg/server/options"
 	"k8s.io/client-go/informers"
+	"k8s.io/component-base/compatibility"
 	"k8s.io/component-base/featuregate"
 )
 
@@ -116,6 +118,7 @@ func (a *AdmissionOptions) ApplyTo(
 	kubeClient kubernetes.Interface,
 	dynamicClient dynamic.Interface,
 	features featuregate.FeatureGate,
+	effectiveVersion compatibility.EffectiveVersion,
 	pluginInitializers ...admission.PluginInitializer,
 ) error {
 	if a == nil {
@@ -127,7 +130,7 @@ func (a *AdmissionOptions) ApplyTo(
 		a.GenericAdmission.EnablePlugins, a.GenericAdmission.DisablePlugins = computePluginNames(a.PluginNames, a.GenericAdmission.RecommendedPluginOrder)
 	}
 
-	return a.GenericAdmission.ApplyTo(c, informers, kubeClient, dynamicClient, features, pluginInitializers...)
+	return a.GenericAdmission.ApplyTo(c, informers, kubeClient, dynamicClient, features, effectiveVersion, pluginInitializers...)
 }
 
 // explicitly disable all plugins that are not in the enabled list

diff --git a/plugin/pkg/admission/defaulttolerationseconds/admission_test.go b/plugin/pkg/admission/defaulttolerationseconds/admission_test.go
@@ -300,7 +300,7 @@ func TestHandles(t *testing.T) {
 // newHandlerForTest returns a handler configured for testing.
 func newHandlerForTest() (*Plugin, error) {
 	handler := NewDefaultTolerationSeconds()
-	pluginInitializer := initializer.New(nil, nil, nil, nil, nil, nil, nil)
+	pluginInitializer := initializer.New(nil, nil, nil, nil, nil, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	return handler, admission.ValidateInitialization(handler)
 }
diff --git a/plugin/pkg/admission/gc/gc_admission_test.go b/plugin/pkg/admission/gc/gc_admission_test.go
@@ -138,7 +138,7 @@ func newGCPermissionsEnforcement() (*gcPermissionsEnforcement, error) {
 		return nil, fmt.Errorf("unexpected error while constructing resource list from fake discovery client: %v", err)
 	}
 	restMapper := restmapper.NewDiscoveryRESTMapper(restMapperRes)
-	genericPluginInitializer := initializer.New(nil, nil, nil, fakeAuthorizer{}, nil, nil, restMapper)
+	genericPluginInitializer := initializer.New(nil, nil, nil, fakeAuthorizer{}, nil, nil, nil, restMapper)
 	pluginInitializer := controlplaneadmission.NewPluginInitializer(nil, nil)
 	initializersChain := apiserveradmission.PluginInitializers{}
 	initializersChain = append(initializersChain, genericPluginInitializer)

diff --git a/plugin/pkg/admission/limitranger/admission_test.go b/plugin/pkg/admission/limitranger/admission_test.go
@@ -891,7 +891,7 @@ func newHandlerForTest(c clientset.Interface) (*LimitRanger, informers.SharedInf
 	if err != nil {
 		return nil, f, err
 	}
-	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil)
+	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	err = admission.ValidateInitialization(handler)
 	return handler, f, err

diff --git a/plugin/pkg/admission/namespace/autoprovision/admission_test.go b/plugin/pkg/admission/namespace/autoprovision/admission_test.go
@@ -41,7 +41,7 @@ import (
 func newHandlerForTest(c clientset.Interface) (admission.MutationInterface, informers.SharedInformerFactory, error) {
 	f := informers.NewSharedInformerFactory(c, 5*time.Minute)
 	handler := NewProvision()
-	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil)
+	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	err := admission.ValidateInitialization(handler)
 	return handler, f, err

diff --git a/plugin/pkg/admission/namespace/exists/admission_test.go b/plugin/pkg/admission/namespace/exists/admission_test.go
@@ -39,7 +39,7 @@ import (
 func newHandlerForTest(c kubernetes.Interface) (admission.ValidationInterface, informers.SharedInformerFactory, error) {
 	f := informers.NewSharedInformerFactory(c, 5*time.Minute)
 	handler := NewExists()
-	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil)
+	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	err := admission.ValidateInitialization(handler)
 	return handler, f, err

diff --git a/plugin/pkg/admission/podnodeselector/admission_test.go b/plugin/pkg/admission/podnodeselector/admission_test.go
@@ -198,7 +198,7 @@ func TestHandles(t *testing.T) {
 func newHandlerForTest(c kubernetes.Interface) (*Plugin, informers.SharedInformerFactory, error) {
 	f := informers.NewSharedInformerFactory(c, 5*time.Minute)
 	handler := NewPodNodeSelector(nil)
-	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil)
+	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	err := admission.ValidateInitialization(handler)
 	return handler, f, err

diff --git a/plugin/pkg/admission/podtolerationrestriction/admission_test.go b/plugin/pkg/admission/podtolerationrestriction/admission_test.go
@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/assert"
+
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -355,7 +356,7 @@ func newHandlerForTest(c kubernetes.Interface) (*Plugin, informers.SharedInforme
 		return nil, nil, err
 	}
 	handler := NewPodTolerationsPlugin(pluginConfig)
-	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil)
+	pluginInitializer := genericadmissioninitializer.New(c, nil, f, nil, nil, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	err = admission.ValidateInitialization(handler)
 	return handler, f, err

diff --git a/plugin/pkg/admission/podtopologylabels/admission_test.go b/plugin/pkg/admission/podtopologylabels/admission_test.go
@@ -226,7 +226,7 @@ func TestPodTopology(t *testing.T) {
 func newHandlerForTest(c kubernetes.Interface) (*Plugin, informers.SharedInformerFactory, error) {
 	factory := informers.NewSharedInformerFactory(c, 5*time.Minute)
 	handler := NewPodTopologyPlugin(defaultConfig) // todo: write additional test cases with non-default config.
-	pluginInitializer := genericadmissioninitializer.New(c, nil, factory, nil, feature.DefaultFeatureGate, nil, nil)
+	pluginInitializer := genericadmissioninitializer.New(c, nil, factory, nil, feature.DefaultFeatureGate, nil, nil, nil)
 	pluginInitializer.Initialize(handler)
 	return handler, factory, admission.ValidateInitialization(handler)
 }
diff --git a/plugin/pkg/admission/resourcequota/admission_test.go b/plugin/pkg/admission/resourcequota/admission_test.go
@@ -118,7 +118,7 @@ func createHandlerWithConfig(kubeClient kubernetes.Interface, informerFactory in
 	}
 
 	initializers := admission.PluginInitializers{
-		genericadmissioninitializer.New(kubeClient, nil, informerFactory, nil, nil, stopCh, nil),
+		genericadmissioninitializer.New(kubeClient, nil, informerFactory, nil, nil, nil, stopCh, nil),
 		controlplaneadmission.NewPluginInitializer(quotaConfiguration, nil),
 	}
 	initializers.Initialize(handler)

diff --git a/plugin/pkg/admission/security/podsecurity/admission.go b/plugin/pkg/admission/security/podsecurity/admission.go
@@ -43,6 +43,7 @@ import (
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
 	corev1listers "k8s.io/client-go/listers/core/v1"
+	"k8s.io/component-base/compatibility"
 	"k8s.io/component-base/featuregate"
 	"k8s.io/component-base/metrics/legacyregistry"
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
@@ -72,6 +73,9 @@ type Plugin struct {
 
 	inspectedFeatureGates bool
 
+	inspectedEffectiveVersion bool
+	emulationVersion          *podsecurityadmissionapi.Version
+
 	client          kubernetes.Interface
 	namespaceLister corev1listers.NamespaceLister
 	podLister       corev1listers.PodLister
@@ -104,16 +108,10 @@ func newPlugin(reader io.Reader) (*Plugin, error) {
 		return nil, err
 	}
 
-	evaluator, err := policy.NewEvaluator(policy.DefaultChecks())
-	if err != nil {
-		return nil, fmt.Errorf("could not create PodSecurityRegistry: %w", err)
-	}
-
 	return &Plugin{
 		Handler: admission.NewHandler(admission.Create, admission.Update),
 		delegate: &podsecurityadmission.Admission{
 			Configuration:    config,
-			Evaluator:        evaluator,
 			Metrics:          getDefaultRecorder(),
 			PodSpecExtractor: podsecurityadmission.DefaultPodSpecExtractor{},
 		},
@@ -146,24 +144,45 @@ func (p *Plugin) updateDelegate() {
 	if p.client == nil {
 		return
 	}
-	p.delegate.PodLister = podsecurityadmission.PodListerFromInformer(p.podLister)
-	p.delegate.NamespaceGetter = podsecurityadmission.NamespaceGetterFromListerAndClient(p.namespaceLister, p.client)
+	if !p.inspectedEffectiveVersion {
+		return
+	}
+	if p.delegate.PodLister == nil {
+		p.delegate.PodLister = podsecurityadmission.PodListerFromInformer(p.podLister)
+	}
+	if p.delegate.NamespaceGetter == nil {
+		p.delegate.NamespaceGetter = podsecurityadmission.NamespaceGetterFromListerAndClient(p.namespaceLister, p.client)
+	}
+	if p.delegate.Evaluator == nil {
+		evaluator, err := policy.NewEvaluator(policy.DefaultChecks(), p.emulationVersion)
+		if err != nil {
+			panic(fmt.Errorf("could not create PodSecurityRegistry: %w", err))
+		}
+		p.delegate.Evaluator = evaluator
+	}
 }
 
-func (c *Plugin) InspectFeatureGates(featureGates featuregate.FeatureGate) {
-	c.inspectedFeatureGates = true
-	policy.RelaxPolicyForUserNamespacePods(featureGates.Enabled(features.UserNamespacesPodSecurityStandards))
-
-	if !featureGates.Enabled(features.ProbeHostPodSecurityStandards) {
-		policy.SkipProbeHostEnforcement()
+func (p *Plugin) InspectEffectiveVersion(version compatibility.EffectiveVersion) {
+	p.inspectedEffectiveVersion = true
+	if !version.EmulationVersion().EqualTo(version.BinaryVersion()) {
+		emulationVersion := podsecurityadmissionapi.MajorMinorVersion(int(version.EmulationVersion().Major()), int(version.EmulationVersion().Minor()))
+		p.emulationVersion = &emulationVersion
 	}
 }
 
+func (p *Plugin) InspectFeatureGates(featureGates featuregate.FeatureGate) {
+	p.inspectedFeatureGates = true
+	policy.RelaxPolicyForUserNamespacePods(featureGates.Enabled(features.UserNamespacesPodSecurityStandards))
+}
+
 // ValidateInitialization ensures all required options are set
 func (p *Plugin) ValidateInitialization() error {
 	if !p.inspectedFeatureGates {
 		return fmt.Errorf("%s did not see feature gates", PluginName)
 	}
+	if !p.inspectedEffectiveVersion {
+		return fmt.Errorf("%s did not see effective version", PluginName)
+	}
 	if err := p.delegate.CompleteConfiguration(); err != nil {
 		return fmt.Errorf("%s configuration error: %w", PluginName, err)
 	}

diff --git a/plugin/pkg/admission/security/podsecurity/admission_test.go b/plugin/pkg/admission/security/podsecurity/admission_test.go
@@ -23,13 +23,16 @@ import (
 	"strings"
 	"testing"
 
+	"sigs.k8s.io/yaml"
+
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/apiserver/pkg/authentication/user"
+	"k8s.io/apiserver/pkg/util/compatibility"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/apiserver/pkg/warning"
 	"k8s.io/client-go/informers"
@@ -40,7 +43,6 @@ import (
 	v1 "k8s.io/kubernetes/pkg/apis/core/v1"
 	podsecurityadmission "k8s.io/pod-security-admission/admission"
 	"k8s.io/utils/ptr"
-	"sigs.k8s.io/yaml"
 )
 
 func TestConvert(t *testing.T) {
@@ -81,6 +83,7 @@ func BenchmarkVerifyPod(b *testing.B) {
 		b.Fatal(err)
 	}
 
+	p.InspectEffectiveVersion(compatibility.DefaultBuildEffectiveVersion())
 	p.InspectFeatureGates(utilfeature.DefaultFeatureGate)
 
 	enforceImplicitPrivilegedNamespace := &corev1.Namespace{ObjectMeta: metav1.ObjectMeta{Name: "enforce-implicit", Labels: map[string]string{}}}
@@ -189,6 +192,7 @@ func BenchmarkVerifyNamespace(b *testing.B) {
 		b.Fatal(err)
 	}
 
+	p.InspectEffectiveVersion(compatibility.DefaultBuildEffectiveVersion())
 	p.InspectFeatureGates(utilfeature.DefaultFeatureGate)
 
 	namespace := "enforce"

diff --git a/staging/src/k8s.io/apiserver/pkg/admission/initializer/initializer.go b/staging/src/k8s.io/apiserver/pkg/admission/initializer/initializer.go
@@ -23,6 +23,7 @@ import (
 	"k8s.io/client-go/dynamic"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
+	"k8s.io/component-base/compatibility"
 	"k8s.io/component-base/featuregate"
 )
 
@@ -32,6 +33,7 @@ type pluginInitializer struct {
 	externalInformers informers.SharedInformerFactory
 	authorizer        authorizer.Authorizer
 	featureGates      featuregate.FeatureGate
+	effectiveVersion  compatibility.EffectiveVersion
 	stopCh            <-chan struct{}
 	restMapper        meta.RESTMapper
 }
@@ -45,6 +47,7 @@ func New(
 	extInformers informers.SharedInformerFactory,
 	authz authorizer.Authorizer,
 	featureGates featuregate.FeatureGate,
+	effectiveVersion compatibility.EffectiveVersion,
 	stopCh <-chan struct{},
 	restMapper meta.RESTMapper,
 ) pluginInitializer {
@@ -54,6 +57,7 @@ func New(
 		externalInformers: extInformers,
 		authorizer:        authz,
 		featureGates:      featureGates,
+		effectiveVersion:  effectiveVersion,
 		stopCh:            stopCh,
 		restMapper:        restMapper,
 	}
@@ -68,6 +72,9 @@ func (i pluginInitializer) Initialize(plugin admission.Interface) {
 	}
 
 	// Second tell the plugin about enabled features, so it can decide whether to start informers or not
+	if wants, ok := plugin.(WantsEffectiveVersion); ok {
+		wants.InspectEffectiveVersion(i.effectiveVersion)
+	}
 	if wants, ok := plugin.(WantsFeatures); ok {
 		wants.InspectFeatureGates(i.featureGates)
 	}

diff --git a/staging/src/k8s.io/apiserver/pkg/admission/initializer/initializer_test.go b/staging/src/k8s.io/apiserver/pkg/admission/initializer/initializer_test.go
@@ -34,7 +34,7 @@ import (
 // TestWantsAuthorizer ensures that the authorizer is injected
 // when the WantsAuthorizer interface is implemented by a plugin.
 func TestWantsAuthorizer(t *testing.T) {
-	target := initializer.New(nil, nil, nil, &TestAuthorizer{}, nil, nil, nil)
+	target := initializer.New(nil, nil, nil, &TestAuthorizer{}, nil, nil, nil, nil)
 	wantAuthorizerAdmission := &WantAuthorizerAdmission{}
 	target.Initialize(wantAuthorizerAdmission)
 	if wantAuthorizerAdmission.auth == nil {
@@ -46,7 +46,7 @@ func TestWantsAuthorizer(t *testing.T) {
 // when the WantsExternalKubeClientSet interface is implemented by a plugin.
 func TestWantsExternalKubeClientSet(t *testing.T) {
 	cs := &fake.Clientset{}
-	target := initializer.New(cs, nil, nil, &TestAuthorizer{}, nil, nil, nil)
+	target := initializer.New(cs, nil, nil, &TestAuthorizer{}, nil, nil, nil, nil)
 	wantExternalKubeClientSet := &WantExternalKubeClientSet{}
 	target.Initialize(wantExternalKubeClientSet)
 	if wantExternalKubeClientSet.cs != cs {
@@ -59,7 +59,7 @@ func TestWantsExternalKubeClientSet(t *testing.T) {
 func TestWantsExternalKubeInformerFactory(t *testing.T) {
 	cs := &fake.Clientset{}
 	sf := informers.NewSharedInformerFactory(cs, time.Duration(1)*time.Second)
-	target := initializer.New(cs, nil, sf, &TestAuthorizer{}, nil, nil, nil)
+	target := initializer.New(cs, nil, sf, &TestAuthorizer{}, nil, nil, nil, nil)
 	wantExternalKubeInformerFactory := &WantExternalKubeInformerFactory{}
 	target.Initialize(wantExternalKubeInformerFactory)
 	if wantExternalKubeInformerFactory.sf != sf {
@@ -71,7 +71,7 @@ func TestWantsExternalKubeInformerFactory(t *testing.T) {
 // when the WantsShutdownSignal interface is implemented by a plugin.
 func TestWantsShutdownNotification(t *testing.T) {
 	stopCh := make(chan struct{})
-	target := initializer.New(nil, nil, nil, &TestAuthorizer{}, nil, stopCh, nil)
+	target := initializer.New(nil, nil, nil, &TestAuthorizer{}, nil, nil, stopCh, nil)
 	wantDrainedNotification := &WantDrainedNotification{}
 	target.Initialize(wantDrainedNotification)
 	if wantDrainedNotification.stopCh == nil {
@@ -153,7 +153,7 @@ func (t *TestAuthorizer) Authorize(ctx context.Context, a authorizer.Attributes)
 }
 
 func TestRESTMapperAdmissionPlugin(t *testing.T) {
-	initializer := initializer.New(nil, nil, nil, &TestAuthorizer{}, nil, nil, &doNothingRESTMapper{})
+	initializer := initializer.New(nil, nil, nil, &TestAuthorizer{}, nil, nil, nil, &doNothingRESTMapper{})
 	wantsRESTMapperAdmission := &WantsRESTMapperAdmissionPlugin{}
 	initializer.Initialize(wantsRESTMapperAdmission)