Implement KMS v2alpha1

- add feature gate
- add encrypted object and run generated_files
- generate protobuf for encrypted object and add unit tests
- move parse endpoint to util and refactor
- refactor interface and remove unused interceptor
- add protobuf generate to update-generated-kms.sh
- add integration tests
- add defaulting for apiVersion in kmsConfiguration
- handle v1/v2 and default in encryption config parsing
- move metrics to own pkg and reuse for v2
- use Marshal and Unmarshal instead of serializer
- add context for all service methods
- check version and keyid for healthz

Signed-off-by: Anish Ramasekar <anish.ramasekar@gmail.com>

hack/update-generated-kms-dockerized.sh

@@ -21,7 +21,9 @@ set -o pipefail
 KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
 KUBE_KMS_V1BETA1="${KUBE_ROOT}/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v1beta1/"
 KUBE_KMS_V2ALPHA1="${KUBE_ROOT}/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v2alpha1/"
+KUBE_KMS_V2="${KUBE_ROOT}/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1/"
 
 source "${KUBE_ROOT}/hack/lib/protoc.sh"
 kube::protoc::generate_proto "${KUBE_KMS_V1BETA1}"
 kube::protoc::generate_proto "${KUBE_KMS_V2ALPHA1}"
+kube::protoc::generate_proto "${KUBE_KMS_V2}"

hack/verify-generated-kms.sh

@@ -26,6 +26,7 @@ KUBE_ROOT=$(dirname "${BASH_SOURCE[0]}")/..
 ERROR="KMS gRPC is out of date. Please run hack/update-generated-kms.sh"
 KUBE_KMS_V1BETA1="${KUBE_ROOT}/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v1beta1/"
 KUBE_KMS_V2ALPHA1="${KUBE_ROOT}/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v2alpha1/"
+KUBE_KMS_V2="${KUBE_ROOT}/staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1/"
 
 source "${KUBE_ROOT}/hack/lib/protoc.sh"
 kube::golang::setup_env
@@ -33,6 +34,7 @@ kube::golang::setup_env
 function cleanup {
 	rm -rf "${KUBE_KMS_V1BETA1}/_tmp/"
 	rm -rf "${KUBE_KMS_V2ALPHA1}/_tmp/"
+	rm -rf "${KUBE_KMS_V2}/_tmp/"
 }
 
 trap cleanup EXIT
@@ -41,9 +43,13 @@ mkdir -p "${KUBE_KMS_V1BETA1}/_tmp"
 cp "${KUBE_KMS_V1BETA1}/api.pb.go" "${KUBE_KMS_V1BETA1}/_tmp/"
 mkdir -p "${KUBE_KMS_V2ALPHA1}/_tmp"
 cp "${KUBE_KMS_V2ALPHA1}/api.pb.go" "${KUBE_KMS_V2ALPHA1}/_tmp/"
+mkdir -p "${KUBE_KMS_V2}/_tmp"
+cp "${KUBE_KMS_V2}/api.pb.go" "${KUBE_KMS_V2}/_tmp/"
 
 KUBE_VERBOSE=3 "${KUBE_ROOT}/hack/update-generated-kms.sh"
 kube::protoc::diff "${KUBE_KMS_V1BETA1}/api.pb.go" "${KUBE_KMS_V1BETA1}/_tmp/api.pb.go" "${ERROR}"
 echo "Generated kms v1beta1 api is up to date."
 kube::protoc::diff "${KUBE_KMS_V2ALPHA1}/api.pb.go" "${KUBE_KMS_V2ALPHA1}/_tmp/api.pb.go" "${ERROR}"
 echo "Generated kms v2alpha1 api is up to date."
+kube::protoc::diff "${KUBE_KMS_V2}/api.pb.go" "${KUBE_KMS_V2}/_tmp/api.pb.go" "${ERROR}"
+echo "Generated kms v2 api is up to date."

staging/src/k8s.io/apiserver/pkg/apis/config/types.go

@@ -86,6 +86,9 @@ type IdentityConfiguration struct{}
 
 // KMSConfiguration contains the name, cache size and path to configuration file for a KMS based envelope transformer.
 type KMSConfiguration struct {
+	// apiVersion of KeyManagementService
+	// +optional
+	APIVersion string
 	// name is the name of the KMS plugin to be used.
 	Name string
 	// cachesize is the maximum number of secrets which are cached in memory. The default value is 1000.

staging/src/k8s.io/apiserver/pkg/apis/config/v1/defaults.go

@@ -24,8 +24,9 @@ import (
 )
 
 var (
-	defaultTimeout         = &metav1.Duration{Duration: 3 * time.Second}
+	defaultTimeout          = &metav1.Duration{Duration: 3 * time.Second}
-	defaultCacheSize int32 = 1000
+	defaultCacheSize  int32 = 1000
+	defaultAPIVersion       = "v1"
 )
 
 func addDefaultingFuncs(scheme *runtime.Scheme) error {
@@ -41,4 +42,8 @@ func SetDefaults_KMSConfiguration(obj *KMSConfiguration) {
 	if obj.CacheSize == nil {
 		obj.CacheSize = &defaultCacheSize
 	}
+
+	if obj.APIVersion == "" {
+		obj.APIVersion = defaultAPIVersion
+	}
 }

staging/src/k8s.io/apiserver/pkg/apis/config/v1/defaults_test.go

@@ -34,12 +34,12 @@ func TestKMSProviderTimeoutDefaults(t *testing.T) {
 		{
 			desc: "timeout not supplied",
 			in:   &KMSConfiguration{},
-			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &defaultCacheSize},
+			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &defaultCacheSize, APIVersion: defaultAPIVersion},
 		},
 		{
 			desc: "timeout supplied",
 			in:   &KMSConfiguration{Timeout: &v1.Duration{Duration: 1 * time.Minute}},
-			want: &KMSConfiguration{Timeout: &v1.Duration{Duration: 1 * time.Minute}, CacheSize: &defaultCacheSize},
+			want: &KMSConfiguration{Timeout: &v1.Duration{Duration: 1 * time.Minute}, CacheSize: &defaultCacheSize, APIVersion: defaultAPIVersion},
 		},
 	}
 
@@ -67,17 +67,45 @@ func TestKMSProviderCacheDefaults(t *testing.T) {
 		{
 			desc: "cache size not supplied",
 			in:   &KMSConfiguration{},
-			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &defaultCacheSize},
+			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &defaultCacheSize, APIVersion: defaultAPIVersion},
 		},
 		{
 			desc: "cache of zero size supplied",
 			in:   &KMSConfiguration{CacheSize: &zero},
-			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &zero},
+			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &zero, APIVersion: defaultAPIVersion},
 		},
 		{
 			desc: "positive cache size supplied",
 			in:   &KMSConfiguration{CacheSize: &ten},
-			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &ten},
+			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &ten, APIVersion: defaultAPIVersion},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			SetDefaults_KMSConfiguration(tt.in)
+			if d := cmp.Diff(tt.want, tt.in); d != "" {
+				t.Fatalf("KMS Provider mismatch (-want +got):\n%s", d)
+			}
+		})
+	}
+}
+
+func TestKMSProviderAPIVersionDefaults(t *testing.T) {
+	testCases := []struct {
+		desc string
+		in   *KMSConfiguration
+		want *KMSConfiguration
+	}{
+		{
+			desc: "apiVersion not supplied",
+			in:   &KMSConfiguration{},
+			want: &KMSConfiguration{Timeout: defaultTimeout, CacheSize: &defaultCacheSize, APIVersion: defaultAPIVersion},
+		},
+		{
+			desc: "apiVersion supplied",
+			in:   &KMSConfiguration{Timeout: &v1.Duration{Duration: 1 * time.Minute}, APIVersion: "v2"},
+			want: &KMSConfiguration{Timeout: &v1.Duration{Duration: 1 * time.Minute}, CacheSize: &defaultCacheSize, APIVersion: "v2"},
 		},
 	}
 

staging/src/k8s.io/apiserver/pkg/apis/config/v1/types.go

@@ -86,6 +86,9 @@ type IdentityConfiguration struct{}
 
 // KMSConfiguration contains the name, cache size and path to configuration file for a KMS based envelope transformer.
 type KMSConfiguration struct {
+	// apiVersion of KeyManagementService
+	// +optional
+	APIVersion string `json:"apiVersion"`
 	// name is the name of the KMS plugin to be used.
 	Name string `json:"name"`
 	// cachesize is the maximum number of secrets which are cached in memory. The default value is 1000.

staging/src/k8s.io/apiserver/pkg/apis/config/v1/zz_generated.conversion.go

@@ -179,6 +179,7 @@ func Convert_config_IdentityConfiguration_To_v1_IdentityConfiguration(in *config
 }
 
 func autoConvert_v1_KMSConfiguration_To_config_KMSConfiguration(in *KMSConfiguration, out *config.KMSConfiguration, s conversion.Scope) error {
+	out.APIVersion = in.APIVersion
 	out.Name = in.Name
 	out.CacheSize = (*int32)(unsafe.Pointer(in.CacheSize))
 	out.Endpoint = in.Endpoint
@@ -192,6 +193,7 @@ func Convert_v1_KMSConfiguration_To_config_KMSConfiguration(in *KMSConfiguration
 }
 
 func autoConvert_config_KMSConfiguration_To_v1_KMSConfiguration(in *config.KMSConfiguration, out *KMSConfiguration, s conversion.Scope) error {
+	out.APIVersion = in.APIVersion
 	out.Name = in.Name
 	out.CacheSize = (*int32)(unsafe.Pointer(in.CacheSize))
 	out.Endpoint = in.Endpoint

staging/src/k8s.io/apiserver/pkg/apis/config/validation/validation.go

@@ -21,22 +21,25 @@ import (
 	"encoding/base64"
 	"fmt"
 	"net/url"
+	"strings"
 
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	"k8s.io/apiserver/pkg/apis/config"
 )
 
 const (
-	moreThanOneElementErr    = "more than one provider specified in a single element, should split into different list elements"
+	moreThanOneElementErr          = "more than one provider specified in a single element, should split into different list elements"
-	keyLenErrFmt             = "secret is not of the expected length, got %d, expected one of %v"
+	keyLenErrFmt                   = "secret is not of the expected length, got %d, expected one of %v"
-	unsupportedSchemeErrFmt  = "unsupported scheme %q for KMS provider, only unix is supported"
+	unsupportedSchemeErrFmt        = "unsupported scheme %q for KMS provider, only unix is supported"
-	atLeastOneRequiredErrFmt = "at least one %s is required"
+	unsupportedKMSAPIVersionErrFmt = "unsupported apiVersion %s for KMS provider, only v1 and v2 are supported"
-	invalidURLErrFmt         = "invalid endpoint for kms provider, error: parse %s: net/url: invalid control character in URL"
+	atLeastOneRequiredErrFmt       = "at least one %s is required"
-	mandatoryFieldErrFmt     = "%s is a mandatory field for a %s"
+	invalidURLErrFmt               = "invalid endpoint for kms provider, error: parse %s: net/url: invalid control character in URL"
-	base64EncodingErr        = "secrets must be base64 encoded"
+	mandatoryFieldErrFmt           = "%s is a mandatory field for a %s"
-	zeroOrNegativeErrFmt     = "%s should be a positive value"
+	base64EncodingErr              = "secrets must be base64 encoded"
-	nonZeroErrFmt            = "%s should be a positive value, or negative to disable"
+	zeroOrNegativeErrFmt           = "%s should be a positive value"
-	encryptionConfigNilErr   = "EncryptionConfiguration can't be nil"
+	nonZeroErrFmt                  = "%s should be a positive value, or negative to disable"
+	encryptionConfigNilErr         = "EncryptionConfiguration can't be nil"
+	invalidKMSConfigNameErrFmt     = "invalid KMS provider name %s, must not contain ':'"
 )
 
 var (
@@ -174,12 +177,12 @@ func validateKey(key config.Key, fieldPath *field.Path, expectedLen []int) field
 
 func validateKMSConfiguration(c *config.KMSConfiguration, fieldPath *field.Path) field.ErrorList {
 	allErrs := field.ErrorList{}
-	if c.Name == "" {
+
-		allErrs = append(allErrs, field.Required(fieldPath.Child("name"), fmt.Sprintf(mandatoryFieldErrFmt, "name", "provider")))
+	allErrs = append(allErrs, validateKMSConfigName(c, fieldPath.Child("name"))...)
-	}
 	allErrs = append(allErrs, validateKMSTimeout(c, fieldPath.Child("timeout"))...)
 	allErrs = append(allErrs, validateKMSEndpoint(c, fieldPath.Child("endpoint"))...)
 	allErrs = append(allErrs, validateKMSCacheSize(c, fieldPath.Child("cachesize"))...)
+	allErrs = append(allErrs, validateKMSAPIVersion(c, fieldPath.Child("apiVersion"))...)
 	return allErrs
 }
 
@@ -218,3 +221,25 @@ func validateKMSEndpoint(c *config.KMSConfiguration, fieldPath *field.Path) fiel
 
 	return allErrs
 }
+
+func validateKMSAPIVersion(c *config.KMSConfiguration, fieldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if c.APIVersion != "v1" && c.APIVersion != "v2" {
+		allErrs = append(allErrs, field.Invalid(fieldPath, c.APIVersion, fmt.Sprintf(unsupportedKMSAPIVersionErrFmt, "apiVersion")))
+	}
+
+	return allErrs
+}
+
+func validateKMSConfigName(c *config.KMSConfiguration, fieldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+	if c.Name == "" {
+		allErrs = append(allErrs, field.Required(fieldPath, fmt.Sprintf(mandatoryFieldErrFmt, "name", "provider")))
+	}
+
+	if c.APIVersion != "v1" && strings.Contains(c.Name, ":") {
+		allErrs = append(allErrs, field.Invalid(fieldPath, c.Name, fmt.Sprintf(invalidKMSConfigNameErrFmt, c.Name)))
+	}
+
+	return allErrs
+}

staging/src/k8s.io/apiserver/pkg/apis/config/validation/validation_test.go

@@ -350,3 +350,79 @@ func TestKMSProviderCacheSize(t *testing.T) {
 		})
 	}
 }
+
+func TestKMSProviderAPIVersion(t *testing.T) {
+	apiVersionField := field.NewPath("Resource").Index(0).Child("Provider").Index(0).Child("KMS").Child("APIVersion")
+
+	testCases := []struct {
+		desc string
+		in   *config.KMSConfiguration
+		want field.ErrorList
+	}{
+		{
+			desc: "valid v1 api version",
+			in:   &config.KMSConfiguration{APIVersion: "v1"},
+			want: field.ErrorList{},
+		},
+		{
+			desc: "valid v2 api version",
+			in:   &config.KMSConfiguration{APIVersion: "v2"},
+			want: field.ErrorList{},
+		},
+		{
+			desc: "invalid api version",
+			in:   &config.KMSConfiguration{APIVersion: "v3"},
+			want: field.ErrorList{
+				field.Invalid(apiVersionField, "v3", fmt.Sprintf(unsupportedKMSAPIVersionErrFmt, "apiVersion")),
+			},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			got := validateKMSAPIVersion(tt.in, apiVersionField)
+			if d := cmp.Diff(tt.want, got); d != "" {
+				t.Fatalf("KMS Provider validation mismatch (-want +got):\n%s", d)
+			}
+		})
+	}
+}
+
+func TestKMSProviderName(t *testing.T) {
+	nameField := field.NewPath("Resource").Index(0).Child("Provider").Index(0).Child("KMS").Child("name")
+
+	testCases := []struct {
+		desc string
+		in   *config.KMSConfiguration
+		want field.ErrorList
+	}{
+		{
+			desc: "valid name",
+			in:   &config.KMSConfiguration{Name: "foo"},
+			want: field.ErrorList{},
+		},
+		{
+			desc: "empty name",
+			in:   &config.KMSConfiguration{},
+			want: field.ErrorList{
+				field.Required(nameField, fmt.Sprintf(mandatoryFieldErrFmt, "name", "provider")),
+			},
+		},
+		{
+			desc: "invalid name with :",
+			in:   &config.KMSConfiguration{Name: "foo:bar"},
+			want: field.ErrorList{
+				field.Invalid(nameField, "foo:bar", fmt.Sprintf(invalidKMSConfigNameErrFmt, "foo:bar")),
+			},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			got := validateKMSConfigName(tt.in, nameField)
+			if d := cmp.Diff(tt.want, got); d != "" {
+				t.Fatalf("KMS Provider validation mismatch (-want +got):\n%s", d)
+			}
+		})
+	}
+}

staging/src/k8s.io/apiserver/pkg/features/kube_features.go

@@ -107,6 +107,13 @@ const (
 	// Allows for updating watchcache resource version with progress notify events.
 	EfficientWatchResumption featuregate.Feature = "EfficientWatchResumption"
 
+	// owner: @aramase
+	// kep: http://kep.k8s.io/3299
+	// alpha: v1.25
+	//
+	// Enables KMS v2 API for encryption at rest.
+	KMSv2 featuregate.Feature = "KMSv2"
+
 	// owner: @jiahuif
 	// kep: http://kep.k8s.io/2887
 	// alpha: v1.23
@@ -205,6 +212,8 @@ var defaultKubernetesFeatureGates = map[featuregate.Feature]featuregate.FeatureS
 
 	EfficientWatchResumption: {Default: true, PreRelease: featuregate.GA, LockToDefault: true},
 
+	KMSv2: {Default: false, PreRelease: featuregate.Alpha},
+
 	OpenAPIEnums: {Default: true, PreRelease: featuregate.Beta},
 
 	OpenAPIV3: {Default: true, PreRelease: featuregate.Beta},

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/config.go

@@ -37,12 +37,15 @@ import (
 	apiserverconfig "k8s.io/apiserver/pkg/apis/config"
 	apiserverconfigv1 "k8s.io/apiserver/pkg/apis/config/v1"
 	"k8s.io/apiserver/pkg/apis/config/validation"
+	"k8s.io/apiserver/pkg/features"
 	"k8s.io/apiserver/pkg/server/healthz"
 	"k8s.io/apiserver/pkg/storage/value"
 	aestransformer "k8s.io/apiserver/pkg/storage/value/encrypt/aes"
 	"k8s.io/apiserver/pkg/storage/value/encrypt/envelope"
+	envelopekmsv2 "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2"
 	"k8s.io/apiserver/pkg/storage/value/encrypt/identity"
 	"k8s.io/apiserver/pkg/storage/value/encrypt/secretbox"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
 )
 
 const (
@@ -50,8 +53,11 @@ const (
 	aesGCMTransformerPrefixV1    = "k8s:enc:aesgcm:v1:"
 	secretboxTransformerPrefixV1 = "k8s:enc:secretbox:v1:"
 	kmsTransformerPrefixV1       = "k8s:enc:kms:v1:"
+	kmsTransformerPrefixV2       = "k8s:enc:kms:v2:"
 	kmsPluginHealthzNegativeTTL  = 3 * time.Second
 	kmsPluginHealthzPositiveTTL  = 20 * time.Second
+	kmsAPIVersionV1              = "v1"
+	kmsAPIVersionV2              = "v2"
 )
 
 type kmsPluginHealthzResponse struct {
@@ -67,12 +73,26 @@ type kmsPluginProbe struct {
 	l            *sync.Mutex
 }
 
+type kmsv2PluginProbe struct {
+	name string
+	ttl  time.Duration
+	envelopekmsv2.Service
+	lastResponse *kmsPluginHealthzResponse
+	l            *sync.Mutex
+}
+
 func (h *kmsPluginProbe) toHealthzCheck(idx int) healthz.HealthChecker {
 	return healthz.NamedCheck(fmt.Sprintf("kms-provider-%d", idx), func(r *http.Request) error {
 		return h.Check()
 	})
 }
 
+func (p *kmsv2PluginProbe) toHealthzCheck(idx int) healthz.HealthChecker {
+	return healthz.NamedCheck(fmt.Sprintf("kms-provider-%d", idx), func(r *http.Request) error {
+		return p.Check()
+	})
+}
+
 // GetKMSPluginHealthzCheckers extracts KMSPluginProbes from the EncryptionConfig.
 func GetKMSPluginHealthzCheckers(filepath string) ([]healthz.HealthChecker, error) {
 	f, err := os.Open(filepath)
@@ -80,47 +100,79 @@ func GetKMSPluginHealthzCheckers(filepath string) ([]healthz.HealthChecker, erro
 		return nil, fmt.Errorf("error opening encryption provider configuration file %q: %v", filepath, err)
 	}
 	defer f.Close()
+
 	var result []healthz.HealthChecker
 	probes, err := getKMSPluginProbes(f)
 	if err != nil {
 		return nil, err
 	}
-
 	for i, p := range probes {
 		probe := p
-		result = append(result, probe.toHealthzCheck(i))
+		switch t := probe.(type) {
+		case *kmsPluginProbe:
+			result = append(result, t.toHealthzCheck(i))
+		case *kmsv2PluginProbe:
+			result = append(result, t.toHealthzCheck(i))
+		default:
+			return nil, fmt.Errorf("unsupported KMS plugin type: %T", t)
+		}
 	}
+
 	return result, nil
 }
 
-func getKMSPluginProbes(reader io.Reader) ([]*kmsPluginProbe, error) {
+func getKMSPluginProbes(reader io.Reader) ([]interface{}, error) {
-	var result []*kmsPluginProbe
+	var result []interface{}
 
 	configFileContents, err := ioutil.ReadAll(reader)
 	if err != nil {
-		return result, fmt.Errorf("could not read content of encryption provider configuration: %v", err)
+		return nil, fmt.Errorf("could not read content of encryption provider configuration: %v", err)
 	}
 
 	config, err := loadConfig(configFileContents)
 	if err != nil {
-		return result, fmt.Errorf("error while parsing encryption provider configuration: %v", err)
+		return nil, fmt.Errorf("error while parsing encryption provider configuration: %v", err)
 	}
 
 	for _, r := range config.Resources {
 		for _, p := range r.Providers {
 			if p.KMS != nil {
-				s, err := envelope.NewGRPCService(p.KMS.Endpoint, p.KMS.Timeout.Duration)
+				switch p.KMS.APIVersion {
-				if err != nil {
+				case kmsAPIVersionV1:
-					return nil, fmt.Errorf("could not configure KMS-Plugin's probe %q, error: %v", p.KMS.Name, err)
+					s, err := envelope.NewGRPCService(p.KMS.Endpoint, p.KMS.Timeout.Duration)
-				}
+					if err != nil {
+						return nil, fmt.Errorf("could not configure KMSv1-Plugin's probe %q, error: %v", p.KMS.Name, err)
+					}
 
-				result = append(result, &kmsPluginProbe{
+					result = append(result, &kmsPluginProbe{
-					name:         p.KMS.Name,
+						name:         p.KMS.Name,
-					ttl:          kmsPluginHealthzNegativeTTL,
+						ttl:          kmsPluginHealthzNegativeTTL,
-					Service:      s,
+						Service:      s,
-					l:            &sync.Mutex{},
+						l:            &sync.Mutex{},
-					lastResponse: &kmsPluginHealthzResponse{},
+						lastResponse: &kmsPluginHealthzResponse{},
-				})
+					})
+
+				case kmsAPIVersionV2:
+					if !utilfeature.DefaultFeatureGate.Enabled(features.KMSv2) {
+						return nil, fmt.Errorf("could not configure KMSv2-Plugin's probe %q, KMSv2 feature is not enabled", p.KMS.Name)
+					}
+
+					s, err := envelopekmsv2.NewGRPCService(p.KMS.Endpoint, p.KMS.Timeout.Duration)
+					if err != nil {
+						return nil, fmt.Errorf("could not configure KMSv2-Plugin's probe %q, error: %v", p.KMS.Name, err)
+					}
+
+					result = append(result, &kmsv2PluginProbe{
+						name:         p.KMS.Name,
+						ttl:          kmsPluginHealthzNegativeTTL,
+						Service:      s,
+						l:            &sync.Mutex{},
+						lastResponse: &kmsPluginHealthzResponse{},
+					})
+
+				default:
+					return nil, fmt.Errorf("could not configure KMS Plugin's probe %q, unsupported KMS API version %q", p.KMS.Name, p.KMS.APIVersion)
+				}
 			}
 		}
 	}
@@ -155,6 +207,53 @@ func (h *kmsPluginProbe) Check() error {
 	return nil
 }
 
+// Check gets the healthz status of the KMSv2-Plugin using the Status() method.
+func (h *kmsv2PluginProbe) Check() error {
+	h.l.Lock()
+	defer h.l.Unlock()
+
+	if (time.Since(h.lastResponse.received)) < h.ttl {
+		return h.lastResponse.err
+	}
+
+	ctx := context.Background()
+	p, err := h.Service.Status(ctx)
+	if err != nil {
+		h.lastResponse = &kmsPluginHealthzResponse{err: err, received: time.Now()}
+		h.ttl = kmsPluginHealthzNegativeTTL
+		return fmt.Errorf("failed to perform status section of the healthz check for KMS Provider %s, error: %v", h.name, err)
+	}
+
+	if err := isKMSv2ProviderHealthy(h.name, p); err != nil {
+		h.lastResponse = &kmsPluginHealthzResponse{err: err, received: time.Now()}
+		h.ttl = kmsPluginHealthzNegativeTTL
+		return err
+	}
+
+	h.lastResponse = &kmsPluginHealthzResponse{err: nil, received: time.Now()}
+	h.ttl = kmsPluginHealthzPositiveTTL
+	return nil
+}
+
+// isKMSv2ProviderHealthy checks if the KMSv2-Plugin is healthy.
+func isKMSv2ProviderHealthy(name string, response *envelopekmsv2.StatusResponse) error {
+	var errs []error
+	if response.Healthz != "ok" {
+		errs = append(errs, fmt.Errorf("got unexpected healthz status: %s", response.Healthz))
+	}
+	if response.Version != envelopekmsv2.KMSAPIVersion {
+		errs = append(errs, fmt.Errorf("expected KMSv2 API version %s, got %s", envelopekmsv2.KMSAPIVersion, response.Version))
+	}
+	if len(response.KeyID) == 0 {
+		errs = append(errs, fmt.Errorf("expected KMSv2 KeyID to be set, got %s", response.KeyID))
+	}
+
+	if err := utilerrors.Reduce(utilerrors.NewAggregate(errs)); err != nil {
+		return fmt.Errorf("kmsv2 Provider %s is not healthy, error: %v", name, err)
+	}
+	return nil
+}
+
 // GetTransformerOverrides returns the transformer overrides by reading and parsing the encryption provider configuration file
 func GetTransformerOverrides(filepath string) (map[schema.GroupResource]value.Transformer, error) {
 	f, err := os.Open(filepath)
@@ -224,8 +323,13 @@ func loadConfig(data []byte) (*apiserverconfig.EncryptionConfiguration, error) {
 	return config, validation.ValidateEncryptionConfiguration(config).ToAggregate()
 }
 
-// The factory to create kms service. This is to make writing test easier.
+var (
-var envelopeServiceFactory = envelope.NewGRPCService
+	// The factory to create kms service. This is to make writing test easier.
+	envelopeServiceFactory = envelope.NewGRPCService
+
+	// The factory to create kmsv2 service.
+	envelopeKMSv2ServiceFactory = envelopekmsv2.NewGRPCService
+)
 
 func prefixTransformers(config *apiserverconfig.ResourceConfiguration) ([]value.PrefixTransformer, error) {
 	var result []value.PrefixTransformer
@@ -243,13 +347,26 @@ func prefixTransformers(config *apiserverconfig.ResourceConfiguration) ([]value.
 		case provider.Secretbox != nil:
 			transformer, err = secretboxPrefixTransformer(provider.Secretbox)
 		case provider.KMS != nil:
-			var envelopeService envelope.Service
+			switch provider.KMS.APIVersion {
-			envelopeService, err = envelopeServiceFactory(provider.KMS.Endpoint, provider.KMS.Timeout.Duration)
+			case kmsAPIVersionV1:
-			if err != nil {
+				var envelopeService envelope.Service
-				return nil, fmt.Errorf("could not configure KMS plugin %q, error: %v", provider.KMS.Name, err)
+				if envelopeService, err = envelopeServiceFactory(provider.KMS.Endpoint, provider.KMS.Timeout.Duration); err != nil {
-			}
+					return nil, fmt.Errorf("could not configure KMS plugin %q, error: %v", provider.KMS.Name, err)
+				}
+				transformer, err = envelopePrefixTransformer(provider.KMS, envelopeService, kmsTransformerPrefixV1)
+			case kmsAPIVersionV2:
+				if !utilfeature.DefaultFeatureGate.Enabled(features.KMSv2) {
+					return nil, fmt.Errorf("could not configure KMSv2 plugin %q, KMSv2 feature is not enabled", provider.KMS.Name)
+				}
 
-			transformer, err = envelopePrefixTransformer(provider.KMS, envelopeService, kmsTransformerPrefixV1)
+				var envelopeService envelopekmsv2.Service
+				if envelopeService, err = envelopeKMSv2ServiceFactory(provider.KMS.Endpoint, provider.KMS.Timeout.Duration); err != nil {
+					return nil, fmt.Errorf("could not configure KMSv2 plugin %q, error: %v", provider.KMS.Name, err)
+				}
+				transformer, err = envelopekmsv2PrefixTransformer(provider.KMS, envelopeService, kmsTransformerPrefixV2)
+			default:
+				return nil, fmt.Errorf("could not configure KMS plugin %q, unsupported KMS API version %q", provider.KMS.Name, provider.KMS.APIVersion)
+			}
 		case provider.Identity != nil:
 			transformer = value.PrefixTransformer{
 				Transformer: identity.NewEncryptCheckTransformer(),
@@ -385,6 +502,18 @@ func envelopePrefixTransformer(config *apiserverconfig.KMSConfiguration, envelop
 	}, nil
 }
 
+func envelopekmsv2PrefixTransformer(config *apiserverconfig.KMSConfiguration, envelopeService envelopekmsv2.Service, prefix string) (value.PrefixTransformer, error) {
+	// using AES-GCM by default for encrypting data with KMSv2
+	envelopeTransformer, err := envelopekmsv2.NewEnvelopeTransformer(envelopeService, int(*config.CacheSize), aestransformer.NewGCMTransformer)
+	if err != nil {
+		return value.PrefixTransformer{}, err
+	}
+	return value.PrefixTransformer{
+		Transformer: envelopeTransformer,
+		Prefix:      []byte(prefix + config.Name + ":"),
+	}, nil
+}
+
 type unionTransformers []value.Transformer
 
 func (u unionTransformers) TransformFromStorage(ctx context.Context, data []byte, dataCtx value.Context) (out []byte, stale bool, err error) {

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/config_test.go

@@ -32,8 +32,12 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	apiserverconfig "k8s.io/apiserver/pkg/apis/config"
+	"k8s.io/apiserver/pkg/features"
 	"k8s.io/apiserver/pkg/storage/value"
 	"k8s.io/apiserver/pkg/storage/value/encrypt/envelope"
+	envelopekmsv2 "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	featuregatetesting "k8s.io/component-base/featuregate/testing"
 )
 
 const (
@@ -81,6 +85,36 @@ func (t *testEnvelopeService) Encrypt(data []byte) ([]byte, error) {
 	return []byte(base64.StdEncoding.EncodeToString(data)), nil
 }
 
+// testKMSv2EnvelopeService is a mock kmsv2 envelope service which can be used to simulate remote Envelope v2 services
+// for testing of the envelope transformer with other transformers.
+type testKMSv2EnvelopeService struct {
+	err error
+}
+
+func (t *testKMSv2EnvelopeService) Decrypt(ctx context.Context, uid string, req *envelopekmsv2.DecryptRequest) ([]byte, error) {
+	if t.err != nil {
+		return nil, t.err
+	}
+	return base64.StdEncoding.DecodeString(string(req.Ciphertext))
+}
+
+func (t *testKMSv2EnvelopeService) Encrypt(ctx context.Context, uid string, data []byte) (*envelopekmsv2.EncryptResponse, error) {
+	if t.err != nil {
+		return nil, t.err
+	}
+	return &envelopekmsv2.EncryptResponse{
+		Ciphertext: []byte(base64.StdEncoding.EncodeToString(data)),
+		KeyID:      "1",
+	}, nil
+}
+
+func (t *testKMSv2EnvelopeService) Status(ctx context.Context) (*envelopekmsv2.StatusResponse, error) {
+	if t.err != nil {
+		return nil, t.err
+	}
+	return &envelopekmsv2.StatusResponse{Healthz: "ok", KeyID: "1", Version: "v2alpha1"}, nil
+}
+
 // The factory method to create mock envelope service.
 func newMockEnvelopeService(endpoint string, timeout time.Duration) (envelope.Service, error) {
 	return &testEnvelopeService{nil}, nil
@@ -91,6 +125,16 @@ func newMockErrorEnvelopeService(endpoint string, timeout time.Duration) (envelo
 	return &testEnvelopeService{errors.New("test")}, nil
 }
 
+// The factory method to create mock envelope kmsv2 service.
+func newMockEnvelopeKMSv2Service(endpoint string, timeout time.Duration) (envelopekmsv2.Service, error) {
+	return &testKMSv2EnvelopeService{nil}, nil
+}
+
+// The factory method to create mock envelope kmsv2 service which always returns error.
+func newMockErrorEnvelopeKMSv2Service(endpoint string, timeout time.Duration) (envelopekmsv2.Service, error) {
+	return &testKMSv2EnvelopeService{errors.New("test")}, nil
+}
+
 func TestLegacyConfig(t *testing.T) {
 	legacyV1Config := "testdata/valid-configs/legacy.yaml"
 	legacyConfigObject, err := loadConfig(mustReadConfig(t, legacyV1Config))
@@ -112,10 +156,11 @@ func TestLegacyConfig(t *testing.T) {
 						},
 					}},
 					{KMS: &apiserverconfig.KMSConfiguration{
-						Name:      "testprovider",
+						APIVersion: "v1",
-						Endpoint:  "unix:///tmp/testprovider.sock",
+						Name:       "testprovider",
-						CacheSize: &cacheSize,
+						Endpoint:   "unix:///tmp/testprovider.sock",
-						Timeout:   &metav1.Duration{Duration: 3 * time.Second},
+						CacheSize:  &cacheSize,
+						Timeout:    &metav1.Duration{Duration: 3 * time.Second},
 					}},
 					{AESCBC: &apiserverconfig.AESConfiguration{
 						Keys: []apiserverconfig.Key{
@@ -138,11 +183,15 @@ func TestLegacyConfig(t *testing.T) {
 }
 
 func TestEncryptionProviderConfigCorrect(t *testing.T) {
+	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.KMSv2, true)()
 	// Set factory for mock envelope service
 	factory := envelopeServiceFactory
+	factoryKMSv2 := envelopeKMSv2ServiceFactory
 	envelopeServiceFactory = newMockEnvelopeService
+	envelopeKMSv2ServiceFactory = newMockEnvelopeKMSv2Service
 	defer func() {
 		envelopeServiceFactory = factory
+		envelopeKMSv2ServiceFactory = factoryKMSv2
 	}()
 
 	// Creates compound/prefix transformers with different ordering of available transformers.
@@ -178,12 +227,19 @@ func TestEncryptionProviderConfigCorrect(t *testing.T) {
 		t.Fatalf("error while parsing configuration file: %s.\nThe file was:\n%s", err, correctConfigWithKMSFirst)
 	}
 
+	correctConfigWithKMSv2First := "testdata/valid-configs/kmsv2-first.yaml"
+	kmsv2FirstTransformerOverrides, err := parseEncryptionConfiguration(mustConfigReader(t, correctConfigWithKMSv2First))
+	if err != nil {
+		t.Fatalf("error while parsing configuration file: %s.\nThe file was:\n%s", err, correctConfigWithKMSv2First)
+	}
+
 	// Pick the transformer for any of the returned resources.
 	identityFirstTransformer := identityFirstTransformerOverrides[schema.ParseGroupResource("secrets")]
 	aesGcmFirstTransformer := aesGcmFirstTransformerOverrides[schema.ParseGroupResource("secrets")]
 	aesCbcFirstTransformer := aesCbcFirstTransformerOverrides[schema.ParseGroupResource("secrets")]
 	secretboxFirstTransformer := secretboxFirstTransformerOverrides[schema.ParseGroupResource("secrets")]
 	kmsFirstTransformer := kmsFirstTransformerOverrides[schema.ParseGroupResource("secrets")]
+	kmsv2FirstTransformer := kmsv2FirstTransformerOverrides[schema.ParseGroupResource("secrets")]
 
 	ctx := context.Background()
 	dataCtx := value.DefaultContext([]byte(sampleContextText))
@@ -198,6 +254,7 @@ func TestEncryptionProviderConfigCorrect(t *testing.T) {
 		{secretboxFirstTransformer, "secretboxFirst"},
 		{identityFirstTransformer, "identityFirst"},
 		{kmsFirstTransformer, "kmsFirst"},
+		{kmsv2FirstTransformer, "kmvs2First"},
 	}
 
 	for _, testCase := range transformers {
@@ -222,22 +279,28 @@ func TestEncryptionProviderConfigCorrect(t *testing.T) {
 }
 
 func TestKMSPluginHealthz(t *testing.T) {
+	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.KMSv2, true)()
+
 	service, err := envelope.NewGRPCService("unix:///tmp/testprovider.sock", 3*time.Second)
 	if err != nil {
 		t.Fatalf("Could not initialize envelopeService, error: %v", err)
 	}
+	serviceKMSv2, err := envelopekmsv2.NewGRPCService("unix:///tmp/testprovider.sock", 3*time.Second)
+	if err != nil {
+		t.Fatalf("Could not initialize kmsv2 envelopeService, error: %v", err)
+	}
 
 	testCases := []struct {
 		desc    string
 		config  string
-		want    []*kmsPluginProbe
+		want    []interface{}
 		wantErr bool
 	}{
 		{
 			desc:   "Install Healthz",
 			config: "testdata/valid-configs/kms/default-timeout.yaml",
-			want: []*kmsPluginProbe{
+			want: []interface{}{
-				{
+				&kmsPluginProbe{
 					name:    "foo",
 					Service: service,
 				},
@@ -246,12 +309,12 @@ func TestKMSPluginHealthz(t *testing.T) {
 		{
 			desc:   "Install multiple healthz",
 			config: "testdata/valid-configs/kms/multiple-providers.yaml",
-			want: []*kmsPluginProbe{
+			want: []interface{}{
-				{
+				&kmsPluginProbe{
 					name:    "foo",
 					Service: service,
 				},
-				{
+				&kmsPluginProbe{
 					name:    "bar",
 					Service: service,
 				},
@@ -261,6 +324,26 @@ func TestKMSPluginHealthz(t *testing.T) {
 			desc:   "No KMS Providers",
 			config: "testdata/valid-configs/aes/aes-gcm.yaml",
 		},
+		{
+			desc:   "Install multiple healthz with v1 and v2",
+			config: "testdata/valid-configs/kms/multiple-providers-kmsv2.yaml",
+			want: []interface{}{
+				&kmsv2PluginProbe{
+					name:    "foo",
+					Service: serviceKMSv2,
+				},
+				&kmsPluginProbe{
+					name:    "bar",
+					Service: service,
+				},
+			},
+		},
+		{
+			desc:    "Invalid API version",
+			config:  "testdata/invalid-configs/kms/invalid-apiversion.yaml",
+			want:    nil,
+			wantErr: true,
+		},
 	}
 
 	for _, tt := range testCases {
@@ -270,7 +353,7 @@ func TestKMSPluginHealthz(t *testing.T) {
 				t.Fatalf("got %v, want nil for error", err)
 			}
 
-			if d := cmp.Diff(tt.want, got, cmp.Comparer(serviceComparer)); d != "" {
+			if d := cmp.Diff(tt.want, got, cmp.Comparer(serviceComparer), cmp.Comparer(serviceKMSv2Comparer)); d != "" {
 				t.Fatalf("HealthzConfig mismatch (-want +got):\n%s", d)
 			}
 		})
@@ -320,12 +403,59 @@ func TestKMSPluginHealthzTTL(t *testing.T) {
 	}
 }
 
+func TestKMSv2PluginHealthzTTL(t *testing.T) {
+	service, _ := newMockEnvelopeKMSv2Service("unix:///tmp/testprovider.sock", 3*time.Second)
+	errService, _ := newMockErrorEnvelopeKMSv2Service("unix:///tmp/testprovider.sock", 3*time.Second)
+
+	testCases := []struct {
+		desc    string
+		probe   *kmsv2PluginProbe
+		wantTTL time.Duration
+	}{
+		{
+			desc: "kmsv2 provider in good state",
+			probe: &kmsv2PluginProbe{
+				name:         "test",
+				ttl:          kmsPluginHealthzNegativeTTL,
+				Service:      service,
+				l:            &sync.Mutex{},
+				lastResponse: &kmsPluginHealthzResponse{},
+			},
+			wantTTL: kmsPluginHealthzPositiveTTL,
+		},
+		{
+			desc: "kmsv2 provider in bad state",
+			probe: &kmsv2PluginProbe{
+				name:         "test",
+				ttl:          kmsPluginHealthzPositiveTTL,
+				Service:      errService,
+				l:            &sync.Mutex{},
+				lastResponse: &kmsPluginHealthzResponse{},
+			},
+			wantTTL: kmsPluginHealthzNegativeTTL,
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			tt.probe.Check()
+			if tt.probe.ttl != tt.wantTTL {
+				t.Fatalf("want ttl %v, got ttl %v", tt.wantTTL, tt.probe.ttl)
+			}
+		})
+	}
+}
+
 // As long as got and want contain envelope.Service we will return true.
 // If got has an envelope.Service and want does note (or vice versa) this will return false.
 func serviceComparer(_, _ envelope.Service) bool {
 	return true
 }
 
+func serviceKMSv2Comparer(_, _ envelopekmsv2.Service) bool {
+	return true
+}
+
 func TestCBCKeyRotationWithOverlappingProviders(t *testing.T) {
 	testCBCKeyRotationWithProviders(
 		t,
@@ -413,3 +543,38 @@ func getTransformerFromEncryptionConfig(t *testing.T, encryptionConfigPath strin
 	}
 	panic("unreachable")
 }
+
+func TestIsKMSv2ProviderHealthyError(t *testing.T) {
+	testCases := []struct {
+		desc           string
+		statusResponse *envelopekmsv2.StatusResponse
+	}{
+		{
+			desc: "healthz status is not ok",
+			statusResponse: &envelopekmsv2.StatusResponse{
+				Healthz: "unhealthy",
+			},
+		},
+		{
+			desc: "version is not v2alpha1",
+			statusResponse: &envelopekmsv2.StatusResponse{
+				Version: "v1beta1",
+			},
+		},
+		{
+			desc: "missing keyID",
+			statusResponse: &envelopekmsv2.StatusResponse{
+				Healthz: "ok",
+				Version: "v2alpha1",
+			},
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			if err := isKMSv2ProviderHealthy("testplugin", tt.statusResponse); err == nil {
+				t.Fatalf("isKMSv2ProviderHealthy() should have returned an error")
+			}
+		})
+	}
+}

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/invalid-configs/kms/invalid-apiversion.yaml

@@ -0,0 +1,15 @@
+kind: EncryptionConfiguration
+apiVersion: apiserver.config.k8s.io/v1
+resources:
+  - resources:
+      - secrets
+    providers:
+      - kms:
+          apiVersion: v3
+          name: foo
+          endpoint: unix:///tmp/testprovider.sock
+          timeout:   15s
+      - kms:
+          name: bar
+          endpoint: unix:///tmp/testprovider.sock
+          timeout:   15s

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/aes-cbc-first.yaml

@@ -14,6 +14,11 @@ resources:
           name: testprovider
           endpoint: unix:///tmp/testprovider.sock
           cachesize: 10
+      - kms:
+          apiVersion: v2
+          name: testproviderv2
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
       - identity: {}
       - secretbox:
           keys:

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/aes-gcm-first.yaml

@@ -18,6 +18,11 @@ resources:
           name: testprovider
           endpoint: unix:///tmp/testprovider.sock
           cachesize: 10
+      - kms:
+          apiVersion: v2
+          name: testproviderv2
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
       - aescbc:
           keys:
             - name: key1

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/identity-first.yaml

@@ -16,6 +16,11 @@ resources:
           name: testprovider
           endpoint: unix:///tmp/testprovider.sock
           cachesize: 10
+      - kms:
+          apiVersion: v2
+          name: testproviderv2
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
       - aescbc:
           keys:
             - name: key1

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/kms-first.yaml

@@ -8,6 +8,11 @@ resources:
           name: testprovider
           endpoint: unix:///tmp/testprovider.sock
           cachesize: 10
+      - kms:
+          apiVersion: v2
+          name: testproviderv2
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
       - secretbox:
           keys:
             - name: key1

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/kms/multiple-providers-kmsv2.yaml

@@ -0,0 +1,15 @@
+kind: EncryptionConfiguration
+apiVersion: apiserver.config.k8s.io/v1
+resources:
+  - resources:
+      - secrets
+    providers:
+      - kms:
+          apiVersion: v2
+          name: foo
+          endpoint: unix:///tmp/testprovider.sock
+          timeout:   15s
+      - kms:
+          name: bar
+          endpoint: unix:///tmp/testprovider.sock
+          timeout:   15s

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/kmsv2-first.yaml

@@ -0,0 +1,32 @@
+kind: EncryptionConfiguration
+apiVersion: apiserver.config.k8s.io/v1
+resources:
+  - resources:
+      - secrets
+    providers:
+      - kms:
+          apiVersion: v2
+          name: testproviderv2
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
+      - kms:
+          name: testprovider
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
+      - secretbox:
+          keys:
+            - name: key1
+              secret: YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXoxMjM0NTY=
+      - aescbc:
+          keys:
+            - name: key1
+              secret: c2VjcmV0IGlzIHNlY3VyZQ==
+            - name: key2
+              secret: dGhpcyBpcyBwYXNzd29yZA==
+      - identity: {}
+      - aesgcm:
+          keys:
+            - name: key1
+              secret: c2VjcmV0IGlzIHNlY3VyZQ==
+            - name: key2
+              secret: dGhpcyBpcyBwYXNzd29yZA==

staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/testdata/valid-configs/secret-box-first.yaml

@@ -18,6 +18,11 @@ resources:
           name: testprovider
           endpoint: unix:///tmp/testprovider.sock
           cachesize: 10
+      - kms:
+          apiVersion: v2
+          name: testproviderv2
+          endpoint: unix:///tmp/testprovider.sock
+          cachesize: 10
       - identity: {}
       - aesgcm:
           keys:

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/envelope.go

@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"k8s.io/apiserver/pkg/storage/value"
+	"k8s.io/apiserver/pkg/storage/value/encrypt/envelope/metrics"
 	"k8s.io/utils/lru"
 
 	"golang.org/x/crypto/cryptobyte"
@@ -34,7 +35,7 @@ import (
 
 func init() {
 	value.RegisterMetrics()
-	registerMetrics()
+	metrics.RegisterMetrics()
 }
 
 // Service allows encrypting and decrypting data using an external Key Management Service.
@@ -81,7 +82,7 @@ func NewEnvelopeTransformer(envelopeService Service, cacheSize int, baseTransfor
 
 // TransformFromStorage decrypts data encrypted by this transformer using envelope encryption.
 func (t *envelopeTransformer) TransformFromStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, bool, error) {
-	recordArrival(fromStorageLabel, time.Now())
+	metrics.RecordArrival(metrics.FromStorageLabel, time.Now())
 
 	// Read the 16 bit length-of-DEK encoded at the start of the encrypted DEK. 16 bits can
 	// represent a maximum key length of 65536 bytes. We are using a 256 bit key, whose
@@ -119,7 +120,7 @@ func (t *envelopeTransformer) TransformFromStorage(ctx context.Context, data []b
 
 // TransformToStorage encrypts data to be written to disk using envelope encryption.
 func (t *envelopeTransformer) TransformToStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, error) {
-	recordArrival(toStorageLabel, time.Now())
+	metrics.RecordArrival(metrics.ToStorageLabel, time.Now())
 	newKey, err := generateKey(32)
 	if err != nil {
 		return nil, err
@@ -165,7 +166,7 @@ func (t *envelopeTransformer) addTransformer(encKey []byte, key []byte) (value.T
 	// cannot hash []uint8.
 	if t.cacheEnabled {
 		t.transformers.Add(base64.StdEncoding.EncodeToString(encKey), transformer)
-		dekCacheFillPercent.Set(float64(t.transformers.Len()) / float64(t.cacheSize))
+		metrics.RecordDekCacheFillPercent(float64(t.transformers.Len()) / float64(t.cacheSize))
 	}
 	return transformer, nil
 }

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/grpc_service.go

@@ -21,8 +21,6 @@ import (
 	"context"
 	"fmt"
 	"net"
-	"net/url"
-	"strings"
 	"sync"
 	"time"
 
@@ -31,13 +29,13 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials/insecure"
 
+	"k8s.io/apiserver/pkg/storage/value/encrypt/envelope/util"
 	kmsapi "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v1beta1"
 )
 
 const (
-	// Now only supported unix domain socket.
+	// unixProtocol is the only supported protocol for remote KMS provider.
 	unixProtocol = "unix"
-
 	// Current version for the protocol interface definition.
 	kmsapiVersion = "v1beta1"
 
@@ -57,7 +55,7 @@ type gRPCService struct {
 func NewGRPCService(endpoint string, callTimeout time.Duration) (Service, error) {
 	klog.V(4).Infof("Configure KMS provider with endpoint: %s", endpoint)
 
-	addr, err := parseEndpoint(endpoint)
+	addr, err := util.ParseEndpoint(endpoint)
 	if err != nil {
 		return nil, err
 	}
@@ -89,32 +87,6 @@ func NewGRPCService(endpoint string, callTimeout time.Duration) (Service, error)
 	return s, nil
 }
 
-// Parse the endpoint to extract schema, host or path.
-func parseEndpoint(endpoint string) (string, error) {
-	if len(endpoint) == 0 {
-		return "", fmt.Errorf("remote KMS provider can't use empty string as endpoint")
-	}
-
-	u, err := url.Parse(endpoint)
-	if err != nil {
-		return "", fmt.Errorf("invalid endpoint %q for remote KMS provider, error: %v", endpoint, err)
-	}
-
-	if u.Scheme != unixProtocol {
-		return "", fmt.Errorf("unsupported scheme %q for remote KMS provider", u.Scheme)
-	}
-
-	// Linux abstract namespace socket - no physical file required
-	// Warning: Linux Abstract sockets have not concept of ACL (unlike traditional file based sockets).
-	// However, Linux Abstract sockets are subject to Linux networking namespace, so will only be accessible to
-	// containers within the same pod (unless host networking is used).
-	if strings.HasPrefix(u.Path, "/@") {
-		return strings.TrimPrefix(u.Path, "/"), nil
-	}
-
-	return u.Path, nil
-}
-
 func (g *gRPCService) checkAPIVersion(ctx context.Context) error {
 	g.mux.Lock()
 	defer g.mux.Unlock()

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/grpc_service_unix_test.go

@@ -27,7 +27,7 @@ import (
 	"testing"
 	"time"
 
-	mock "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing"
+	mock "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1"
 
 	"k8s.io/apimachinery/pkg/util/uuid"
 )

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/envelope.go

@@ -0,0 +1,246 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package kmsv2 transforms values for storage at rest using a Envelope v2 provider
+package kmsv2
+
+import (
+	"context"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+	"k8s.io/apimachinery/pkg/util/uuid"
+	"k8s.io/apiserver/pkg/storage/value"
+	kmstypes "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1"
+	"k8s.io/apiserver/pkg/storage/value/encrypt/envelope/metrics"
+	"k8s.io/utils/lru"
+)
+
+const (
+	// KMSAPIVersion is the version of the KMS API.
+	KMSAPIVersion = "v2alpha1"
+)
+
+// Service allows encrypting and decrypting data using an external Key Management Service.
+type Service interface {
+	// Decrypt a given bytearray to obtain the original data as bytes.
+	Decrypt(ctx context.Context, uid string, req *DecryptRequest) ([]byte, error)
+	// Encrypt bytes to a ciphertext.
+	Encrypt(ctx context.Context, uid string, data []byte) (*EncryptResponse, error)
+	// Status returns the status of the KMS.
+	Status(ctx context.Context) (*StatusResponse, error)
+}
+
+type envelopeTransformer struct {
+	envelopeService Service
+
+	// transformers is a thread-safe LRU cache which caches decrypted DEKs indexed by their encrypted form.
+	transformers *lru.Cache
+
+	// baseTransformerFunc creates a new transformer for encrypting the data with the DEK.
+	baseTransformerFunc func(cipher.Block) value.Transformer
+
+	cacheSize    int
+	cacheEnabled bool
+
+	pluginName string
+}
+
+// EncryptResponse is the response from the Envelope service when encrypting data.
+type EncryptResponse struct {
+	Ciphertext  []byte
+	KeyID       string
+	Annotations map[string][]byte
+}
+
+// DecryptRequest is the request to the Envelope service when decrypting data.
+type DecryptRequest struct {
+	Ciphertext  []byte
+	KeyID       string
+	Annotations map[string][]byte
+}
+
+// StatusResponse is the response from the Envelope service when getting the status of the service.
+type StatusResponse struct {
+	Version string
+	Healthz string
+	KeyID   string
+}
+
+// NewEnvelopeTransformer returns a transformer which implements a KEK-DEK based envelope encryption scheme.
+// It uses envelopeService to encrypt and decrypt DEKs. Respective DEKs (in encrypted form) are prepended to
+// the data items they encrypt. A cache (of size cacheSize) is maintained to store the most recently
+// used decrypted DEKs in memory.
+func NewEnvelopeTransformer(envelopeService Service, cacheSize int, baseTransformerFunc func(cipher.Block) value.Transformer) (value.Transformer, error) {
+	var cache *lru.Cache
+
+	if cacheSize > 0 {
+		// TODO(aramase): Switch to using expiring cache: kubernetes/kubernetes/staging/src/k8s.io/apimachinery/pkg/util/cache/expiring.go.
+		// It handles scans a lot better, doesn't have to be right sized, and don't have a global lock on reads.
+		cache = lru.New(cacheSize)
+	}
+
+	return &envelopeTransformer{
+		envelopeService:     envelopeService,
+		transformers:        cache,
+		baseTransformerFunc: baseTransformerFunc,
+		cacheEnabled:        cacheSize > 0,
+		cacheSize:           cacheSize,
+	}, nil
+}
+
+// TransformFromStorage decrypts data encrypted by this transformer using envelope encryption.
+func (t *envelopeTransformer) TransformFromStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, bool, error) {
+	metrics.RecordArrival(metrics.FromStorageLabel, time.Now())
+
+	// Deserialize the EncryptedObject from the data.
+	encryptedObject, err := t.doDecode(data)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Look up the decrypted DEK from cache or Envelope.
+	transformer := t.getTransformer(encryptedObject.EncryptedDEK)
+	if transformer == nil {
+		if t.cacheEnabled {
+			value.RecordCacheMiss()
+		}
+		uid := string(uuid.NewUUID())
+		key, err := t.envelopeService.Decrypt(ctx, uid, &DecryptRequest{
+			Ciphertext:  encryptedObject.EncryptedDEK,
+			KeyID:       encryptedObject.KeyID,
+			Annotations: encryptedObject.Annotations,
+		})
+		if err != nil {
+			return nil, false, fmt.Errorf("failed to decrypt DEK, error: %w", err)
+		}
+
+		transformer, err = t.addTransformer(encryptedObject.EncryptedDEK, key)
+		if err != nil {
+			return nil, false, err
+		}
+	}
+
+	return transformer.TransformFromStorage(ctx, encryptedObject.EncryptedData, dataCtx)
+}
+
+// TransformToStorage encrypts data to be written to disk using envelope encryption.
+func (t *envelopeTransformer) TransformToStorage(ctx context.Context, data []byte, dataCtx value.Context) ([]byte, error) {
+	metrics.RecordArrival(metrics.ToStorageLabel, time.Now())
+	newKey, err := generateKey(32)
+	if err != nil {
+		return nil, err
+	}
+
+	uid := string(uuid.NewUUID())
+	resp, err := t.envelopeService.Encrypt(ctx, uid, newKey)
+	if err != nil {
+		return nil, fmt.Errorf("failed to encrypt DEK, error: %w", err)
+	}
+
+	transformer, err := t.addTransformer(resp.Ciphertext, newKey)
+	if err != nil {
+		return nil, err
+	}
+
+	result, err := transformer.TransformToStorage(ctx, data, dataCtx)
+	if err != nil {
+		return nil, err
+	}
+
+	encObject := &kmstypes.EncryptedObject{
+		KeyID:         resp.KeyID,
+		EncryptedDEK:  resp.Ciphertext,
+		EncryptedData: result,
+		Annotations:   resp.Annotations,
+	}
+
+	// Serialize the EncryptedObject to a byte array.
+	return t.doEncode(encObject)
+}
+
+// addTransformer inserts a new transformer to the Envelope cache of DEKs for future reads.
+func (t *envelopeTransformer) addTransformer(encKey []byte, key []byte) (value.Transformer, error) {
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+	transformer := t.baseTransformerFunc(block)
+	// Use base64 of encKey as the key into the cache because hashicorp/golang-lru
+	// cannot hash []uint8.
+	if t.cacheEnabled {
+		t.transformers.Add(base64.StdEncoding.EncodeToString(encKey), transformer)
+		metrics.RecordDekCacheFillPercent(float64(t.transformers.Len()) / float64(t.cacheSize))
+	}
+	return transformer, nil
+}
+
+// getTransformer fetches the transformer corresponding to encKey from cache, if it exists.
+func (t *envelopeTransformer) getTransformer(encKey []byte) value.Transformer {
+	if !t.cacheEnabled {
+		return nil
+	}
+
+	_transformer, found := t.transformers.Get(base64.StdEncoding.EncodeToString(encKey))
+	if found {
+		return _transformer.(value.Transformer)
+	}
+	return nil
+}
+
+// doEncode encodes the EncryptedObject to a byte array.
+func (t *envelopeTransformer) doEncode(request *kmstypes.EncryptedObject) ([]byte, error) {
+	return proto.Marshal(request)
+}
+
+// doDecode decodes the byte array to an EncryptedObject.
+func (t *envelopeTransformer) doDecode(originalData []byte) (*kmstypes.EncryptedObject, error) {
+	o := &kmstypes.EncryptedObject{}
+	if err := proto.Unmarshal(originalData, o); err != nil {
+		return nil, err
+	}
+
+	// validate the EncryptedObject
+	if o.EncryptedData == nil {
+		return nil, fmt.Errorf("encrypted data is nil after unmarshal")
+	}
+	if o.KeyID == "" {
+		return nil, fmt.Errorf("keyID is empty after unmarshal")
+	}
+	if o.EncryptedDEK == nil {
+		return nil, fmt.Errorf("encrypted dek is nil after unmarshal")
+	}
+
+	return o, nil
+}
+
+// generateKey generates a random key using system randomness.
+func generateKey(length int) (key []byte, err error) {
+	defer func(start time.Time) {
+		value.RecordDataKeyGeneration(start, err)
+	}(time.Now())
+	key = make([]byte, length)
+	if _, err = rand.Read(key); err != nil {
+		return nil, err
+	}
+
+	return key, nil
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/envelope_test.go

@@ -0,0 +1,262 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package kmsv2 transforms values for storage at rest using a Envelope v2 provider
+package kmsv2
+
+import (
+	"bytes"
+	"context"
+	"encoding/base64"
+	"fmt"
+	"reflect"
+	"strconv"
+	"testing"
+
+	"k8s.io/apiserver/pkg/storage/value"
+	aestransformer "k8s.io/apiserver/pkg/storage/value/encrypt/aes"
+	kmstypes "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1"
+)
+
+const (
+	testText              = "abcdefghijklmnopqrstuvwxyz"
+	testContextText       = "0123456789"
+	testEnvelopeCacheSize = 10
+)
+
+// testEnvelopeService is a mock Envelope service which can be used to simulate remote Envelope services
+// for testing of Envelope based encryption providers.
+type testEnvelopeService struct {
+	disabled   bool
+	keyVersion string
+}
+
+func (t *testEnvelopeService) Decrypt(ctx context.Context, uid string, req *DecryptRequest) ([]byte, error) {
+	if t.disabled {
+		return nil, fmt.Errorf("Envelope service was disabled")
+	}
+	if len(uid) == 0 {
+		return nil, fmt.Errorf("uid is required")
+	}
+	if len(req.KeyID) == 0 {
+		return nil, fmt.Errorf("keyID is required")
+	}
+	return base64.StdEncoding.DecodeString(string(req.Ciphertext))
+}
+
+func (t *testEnvelopeService) Encrypt(ctx context.Context, uid string, data []byte) (*EncryptResponse, error) {
+	if t.disabled {
+		return nil, fmt.Errorf("Envelope service was disabled")
+	}
+	if len(uid) == 0 {
+		return nil, fmt.Errorf("uid is required")
+	}
+	return &EncryptResponse{Ciphertext: []byte(base64.StdEncoding.EncodeToString(data)), KeyID: t.keyVersion, Annotations: map[string][]byte{"kms.kubernetes.io/local-kek": []byte("encrypted-local-kek")}}, nil
+}
+
+func (t *testEnvelopeService) Status(ctx context.Context) (*StatusResponse, error) {
+	if t.disabled {
+		return nil, fmt.Errorf("Envelope service was disabled")
+	}
+	return &StatusResponse{KeyID: t.keyVersion}, nil
+}
+
+func (t *testEnvelopeService) SetDisabledStatus(status bool) {
+	t.disabled = status
+}
+
+func (t *testEnvelopeService) Rotate() {
+	i, _ := strconv.Atoi(t.keyVersion)
+	t.keyVersion = strconv.FormatInt(int64(i+1), 10)
+}
+
+func newTestEnvelopeService() *testEnvelopeService {
+	return &testEnvelopeService{
+		keyVersion: "1",
+	}
+}
+
+// Throw error if Envelope transformer tries to contact Envelope without hitting cache.
+func TestEnvelopeCaching(t *testing.T) {
+	testCases := []struct {
+		desc                     string
+		cacheSize                int
+		simulateKMSPluginFailure bool
+	}{
+		{
+			desc:                     "positive cache size should withstand plugin failure",
+			cacheSize:                1000,
+			simulateKMSPluginFailure: true,
+		},
+		{
+			desc:      "cache disabled size should not withstand plugin failure",
+			cacheSize: 0,
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			envelopeService := newTestEnvelopeService()
+			envelopeTransformer, err := NewEnvelopeTransformer(envelopeService, tt.cacheSize, aestransformer.NewGCMTransformer)
+			if err != nil {
+				t.Fatalf("failed to initialize envelope transformer: %v", err)
+			}
+			ctx := context.Background()
+			dataCtx := value.DefaultContext([]byte(testContextText))
+			originalText := []byte(testText)
+
+			transformedData, err := envelopeTransformer.TransformToStorage(ctx, originalText, dataCtx)
+			if err != nil {
+				t.Fatalf("envelopeTransformer: error while transforming data to storage: %s", err)
+			}
+			untransformedData, _, err := envelopeTransformer.TransformFromStorage(ctx, transformedData, dataCtx)
+			if err != nil {
+				t.Fatalf("could not decrypt Envelope transformer's encrypted data even once: %v", err)
+			}
+			if !bytes.Equal(untransformedData, originalText) {
+				t.Fatalf("envelopeTransformer transformed data incorrectly. Expected: %v, got %v", originalText, untransformedData)
+			}
+
+			envelopeService.SetDisabledStatus(tt.simulateKMSPluginFailure)
+			// Subsequent read for the same data should work fine due to caching.
+			untransformedData, _, err = envelopeTransformer.TransformFromStorage(ctx, transformedData, dataCtx)
+			if err != nil {
+				t.Fatalf("could not decrypt Envelope transformer's encrypted data using just cache: %v", err)
+			}
+			if !bytes.Equal(untransformedData, originalText) {
+				t.Fatalf("envelopeTransformer transformed data incorrectly using cache. Got: %v, want %v", untransformedData, originalText)
+			}
+		})
+	}
+}
+
+// Makes Envelope transformer hit cache limit, throws error if it misbehaves.
+func TestEnvelopeCacheLimit(t *testing.T) {
+	envelopeTransformer, err := NewEnvelopeTransformer(newTestEnvelopeService(), testEnvelopeCacheSize, aestransformer.NewGCMTransformer)
+	if err != nil {
+		t.Fatalf("failed to initialize envelope transformer: %v", err)
+	}
+	ctx := context.Background()
+	dataCtx := value.DefaultContext([]byte(testContextText))
+
+	transformedOutputs := map[int][]byte{}
+
+	// Overwrite lots of entries in the map
+	for i := 0; i < 2*testEnvelopeCacheSize; i++ {
+		numberText := []byte(strconv.Itoa(i))
+
+		res, err := envelopeTransformer.TransformToStorage(ctx, numberText, dataCtx)
+		transformedOutputs[i] = res
+		if err != nil {
+			t.Fatalf("envelopeTransformer: error while transforming data (%v) to storage: %s", numberText, err)
+		}
+	}
+
+	// Try reading all the data now, ensuring cache misses don't cause a concern.
+	for i := 0; i < 2*testEnvelopeCacheSize; i++ {
+		numberText := []byte(strconv.Itoa(i))
+
+		output, _, err := envelopeTransformer.TransformFromStorage(ctx, transformedOutputs[i], dataCtx)
+		if err != nil {
+			t.Fatalf("envelopeTransformer: error while transforming data (%v) from storage: %s", transformedOutputs[i], err)
+		}
+
+		if !bytes.Equal(numberText, output) {
+			t.Fatalf("envelopeTransformer transformed data incorrectly using cache. Expected: %v, got %v", numberText, output)
+		}
+	}
+}
+
+func TestEncodeDecode(t *testing.T) {
+	envelopeTransformer := &envelopeTransformer{
+		pluginName: "testplugin",
+	}
+
+	obj := &kmstypes.EncryptedObject{
+		EncryptedData: []byte{0x01, 0x02, 0x03},
+		KeyID:         "1",
+		EncryptedDEK:  []byte{0x04, 0x05, 0x06},
+	}
+
+	data, err := envelopeTransformer.doEncode(obj)
+	if err != nil {
+		t.Fatalf("envelopeTransformer: error while encoding data: %s", err)
+	}
+	got, err := envelopeTransformer.doDecode(data)
+	if err != nil {
+		t.Fatalf("envelopeTransformer: error while decoding data: %s", err)
+	}
+	// reset internal field modified by marshaling obj
+	obj.XXX_sizecache = 0
+	if !reflect.DeepEqual(got, obj) {
+		t.Fatalf("envelopeTransformer: decoded data does not match original data. Got: %v, want %v", got, obj)
+	}
+}
+
+func TestDecodeError(t *testing.T) {
+	et := &envelopeTransformer{
+		pluginName: "testplugin",
+	}
+
+	testCases := []struct {
+		desc          string
+		originalData  func() []byte
+		expectedError error
+	}{
+		{
+			desc: "encrypted data is nil",
+			originalData: func() []byte {
+				data, _ := et.doEncode(&kmstypes.EncryptedObject{})
+				return data
+			},
+			expectedError: fmt.Errorf("encrypted data is nil after unmarshal"),
+		},
+		{
+			desc: "keyID is nil",
+			originalData: func() []byte {
+				data, _ := et.doEncode(&kmstypes.EncryptedObject{
+					EncryptedData: []byte{0x01, 0x02, 0x03},
+				})
+				return data
+			},
+			expectedError: fmt.Errorf("keyID is empty after unmarshal"),
+		},
+		{
+			desc: "encrypted dek is nil",
+			originalData: func() []byte {
+				data, _ := et.doEncode(&kmstypes.EncryptedObject{
+					EncryptedData: []byte{0x01, 0x02, 0x03},
+					KeyID:         "1",
+				})
+				return data
+			},
+			expectedError: fmt.Errorf("encrypted dek is nil after unmarshal"),
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			_, err := et.doDecode(tt.originalData())
+			if err == nil {
+				t.Fatalf("envelopeTransformer: expected error while decoding data, got nil")
+			}
+
+			if err.Error() != tt.expectedError.Error() {
+				t.Fatalf("doDecode() error: expected %v, got %v", tt.expectedError, err)
+			}
+		})
+	}
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/grpc_service.go

@@ -0,0 +1,130 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package kmsv2 transforms values for storage at rest using a Envelope provider
+package kmsv2
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"time"
+
+	"k8s.io/klog/v2"
+
+	"google.golang.org/grpc"
+
+	"k8s.io/apiserver/pkg/storage/value/encrypt/envelope/util"
+	kmsapi "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v2alpha1"
+)
+
+const (
+	// unixProtocol is the only supported protocol for remote KMS provider.
+	unixProtocol = "unix"
+)
+
+// The gRPC implementation for envelope.Service.
+type gRPCService struct {
+	kmsClient   kmsapi.KeyManagementServiceClient
+	connection  *grpc.ClientConn
+	callTimeout time.Duration
+}
+
+// NewGRPCService returns an envelope.Service which use gRPC to communicate the remote KMS provider.
+func NewGRPCService(endpoint string, callTimeout time.Duration) (Service, error) {
+	klog.V(4).Infof("Configure KMS provider with endpoint: %s", endpoint)
+
+	addr, err := util.ParseEndpoint(endpoint)
+	if err != nil {
+		return nil, err
+	}
+
+	s := &gRPCService{callTimeout: callTimeout}
+	s.connection, err = grpc.Dial(
+		addr,
+		grpc.WithInsecure(),
+		grpc.WithDefaultCallOptions(grpc.WaitForReady(true)),
+		grpc.WithContextDialer(
+			func(context.Context, string) (net.Conn, error) {
+				// Ignoring addr and timeout arguments:
+				// addr - comes from the closure
+				c, err := net.DialUnix(unixProtocol, nil, &net.UnixAddr{Name: addr})
+				if err != nil {
+					klog.Errorf("failed to create connection to unix socket: %s, error: %v", addr, err)
+				} else {
+					klog.V(4).Infof("Successfully dialed Unix socket %v", addr)
+				}
+				return c, err
+			}))
+
+	if err != nil {
+		return nil, fmt.Errorf("failed to create connection to %s, error: %v", endpoint, err)
+	}
+
+	s.kmsClient = kmsapi.NewKeyManagementServiceClient(s.connection)
+	return s, nil
+}
+
+// Decrypt a given data string to obtain the original byte data.
+func (g *gRPCService) Decrypt(ctx context.Context, uid string, req *DecryptRequest) ([]byte, error) {
+	ctx, cancel := context.WithTimeout(ctx, g.callTimeout)
+	defer cancel()
+
+	request := &kmsapi.DecryptRequest{
+		Ciphertext:  req.Ciphertext,
+		Uid:         uid,
+		KeyId:       req.KeyID,
+		Annotations: req.Annotations,
+	}
+	response, err := g.kmsClient.Decrypt(ctx, request)
+	if err != nil {
+		return nil, err
+	}
+	return response.Plaintext, nil
+}
+
+// Encrypt bytes to a string ciphertext.
+func (g *gRPCService) Encrypt(ctx context.Context, uid string, plaintext []byte) (*EncryptResponse, error) {
+	ctx, cancel := context.WithTimeout(ctx, g.callTimeout)
+	defer cancel()
+
+	request := &kmsapi.EncryptRequest{
+		Plaintext: plaintext,
+		Uid:       uid,
+	}
+	response, err := g.kmsClient.Encrypt(ctx, request)
+	if err != nil {
+		return nil, err
+	}
+	return &EncryptResponse{
+		Ciphertext:  response.Ciphertext,
+		KeyID:       response.KeyId,
+		Annotations: response.Annotations,
+	}, nil
+}
+
+// Status returns the status of the KMSv2 provider.
+func (g *gRPCService) Status(ctx context.Context) (*StatusResponse, error) {
+	ctx, cancel := context.WithTimeout(ctx, g.callTimeout)
+	defer cancel()
+
+	request := &kmsapi.StatusRequest{}
+	response, err := g.kmsClient.Status(ctx, request)
+	if err != nil {
+		return nil, err
+	}
+	return &StatusResponse{Version: response.Version, Healthz: response.Healthz, KeyID: response.KeyId}, nil
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/grpc_service_unix_test.go

@@ -0,0 +1,388 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package kmsv2 transforms values for storage at rest using a Envelope v2 provider
+package kmsv2
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+	"sync"
+	"testing"
+	"time"
+
+	mock "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v2alpha1"
+
+	"k8s.io/apimachinery/pkg/util/uuid"
+)
+
+type testSocket struct {
+	path     string
+	endpoint string
+}
+
+// newEndpoint constructs a unique name for a Linux Abstract Socket to be used in a test.
+// This package uses Linux Domain Sockets to remove the need for clean-up of socket files.
+func newEndpoint() *testSocket {
+	p := fmt.Sprintf("@%s.sock", uuid.NewUUID())
+
+	return &testSocket{
+		path:     p,
+		endpoint: fmt.Sprintf("unix:///%s", p),
+	}
+}
+
+// TestKMSPluginLateStart tests the scenario where kms-plugin pod/container starts after kube-apiserver pod/container.
+// Since the Dial to kms-plugin is non-blocking we expect the construction of gRPC service to succeed even when
+// kms-plugin is not yet up - dialing happens in the background.
+func TestKMSPluginLateStart(t *testing.T) {
+	t.Parallel()
+	callTimeout := 3 * time.Second
+	s := newEndpoint()
+
+	service, err := NewGRPCService(s.endpoint, callTimeout)
+	if err != nil {
+		t.Fatalf("failed to create envelope service, error: %v", err)
+	}
+	defer destroyService(service)
+
+	time.Sleep(callTimeout / 2)
+	f, err := mock.NewBase64Plugin(s.path)
+	if err != nil {
+		t.Fatalf("failed to start test KMS provider server, error: %v", err)
+	}
+	if err := f.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer f.CleanUp()
+
+	data := []byte("test data")
+	uid := string(uuid.NewUUID())
+	_, err = service.Encrypt(context.Background(), uid, data)
+	if err != nil {
+		t.Fatalf("failed when execute encrypt, error: %v", err)
+	}
+}
+
+func TestTimeouts(t *testing.T) {
+	t.Parallel()
+	var testCases = []struct {
+		desc               string
+		callTimeout        time.Duration
+		pluginDelay        time.Duration
+		kubeAPIServerDelay time.Duration
+		wantErr            string
+	}{
+		{
+			desc:        "timeout zero - expect failure when call from kube-apiserver arrives before plugin starts",
+			callTimeout: 0 * time.Second,
+			pluginDelay: 3 * time.Second,
+			wantErr:     "rpc error: code = DeadlineExceeded desc = context deadline exceeded",
+		},
+		{
+			desc:               "timeout zero but kms-plugin already up - still failure - zero timeout is an invalid value",
+			callTimeout:        0 * time.Second,
+			pluginDelay:        0 * time.Second,
+			kubeAPIServerDelay: 2 * time.Second,
+			wantErr:            "rpc error: code = DeadlineExceeded desc = context deadline exceeded",
+		},
+		{
+			desc:        "timeout greater than kms-plugin delay - expect success",
+			callTimeout: 6 * time.Second,
+			pluginDelay: 3 * time.Second,
+		},
+		{
+			desc:        "timeout less than kms-plugin delay - expect failure",
+			callTimeout: 3 * time.Second,
+			pluginDelay: 6 * time.Second,
+			wantErr:     "rpc error: code = DeadlineExceeded desc = context deadline exceeded",
+		},
+	}
+
+	for _, tt := range testCases {
+		tt := tt
+		t.Run(tt.desc, func(t *testing.T) {
+			t.Parallel()
+			var (
+				service         Service
+				err             error
+				data            = []byte("test data")
+				uid             = string(uuid.NewUUID())
+				kubeAPIServerWG sync.WaitGroup
+				kmsPluginWG     sync.WaitGroup
+				testCompletedWG sync.WaitGroup
+				socketName      = newEndpoint()
+			)
+
+			testCompletedWG.Add(1)
+			defer testCompletedWG.Done()
+
+			kubeAPIServerWG.Add(1)
+			go func() {
+				// Simulating late start of kube-apiserver - plugin is up before kube-apiserver, if requested by the testcase.
+				time.Sleep(tt.kubeAPIServerDelay)
+
+				service, err = NewGRPCService(socketName.endpoint, tt.callTimeout)
+				if err != nil {
+					t.Fatalf("failed to create envelope service, error: %v", err)
+				}
+				defer destroyService(service)
+				kubeAPIServerWG.Done()
+				// Keeping kube-apiserver up to process requests.
+				testCompletedWG.Wait()
+			}()
+
+			kmsPluginWG.Add(1)
+			go func() {
+				// Simulating delayed start of kms-plugin, kube-apiserver is up before the plugin, if requested by the testcase.
+				time.Sleep(tt.pluginDelay)
+
+				f, err := mock.NewBase64Plugin(socketName.path)
+				if err != nil {
+					t.Fatalf("failed to construct test KMS provider server, error: %v", err)
+				}
+				if err := f.Start(); err != nil {
+					t.Fatalf("Failed to start test KMS provider server, error: %v", err)
+				}
+				defer f.CleanUp()
+				kmsPluginWG.Done()
+				// Keeping plugin up to process requests.
+				testCompletedWG.Wait()
+			}()
+
+			kubeAPIServerWG.Wait()
+			_, err = service.Encrypt(context.Background(), uid, data)
+
+			if err == nil && tt.wantErr != "" {
+				t.Fatalf("got nil, want %s", tt.wantErr)
+			}
+
+			if err != nil && tt.wantErr == "" {
+				t.Fatalf("got %q, want nil", err.Error())
+			}
+
+			// Collecting kms-plugin - allowing plugin to clean-up.
+			kmsPluginWG.Wait()
+		})
+	}
+}
+
+// TestIntermittentConnectionLoss tests the scenario where the connection with kms-plugin is intermittently lost.
+func TestIntermittentConnectionLoss(t *testing.T) {
+	t.Parallel()
+	var (
+		wg1        sync.WaitGroup
+		wg2        sync.WaitGroup
+		timeout    = 30 * time.Second
+		blackOut   = 1 * time.Second
+		data       = []byte("test data")
+		uid        = string(uuid.NewUUID())
+		endpoint   = newEndpoint()
+		encryptErr error
+	)
+	// Start KMS Plugin
+	f, err := mock.NewBase64Plugin(endpoint.path)
+	if err != nil {
+		t.Fatalf("failed to start test KMS provider server, error: %v", err)
+	}
+	if err := f.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+
+	//  connect to kms plugin
+	service, err := NewGRPCService(endpoint.endpoint, timeout)
+	if err != nil {
+		t.Fatalf("failed to create envelope service, error: %v", err)
+	}
+	defer destroyService(service)
+
+	ctx := context.Background()
+	_, err = service.Encrypt(ctx, uid, data)
+	if err != nil {
+		t.Fatalf("failed when execute encrypt, error: %v", err)
+	}
+	t.Log("Connected to KMSPlugin")
+
+	// Stop KMS Plugin - simulating connection loss
+	t.Log("KMS Plugin is stopping")
+	f.CleanUp()
+	time.Sleep(2 * time.Second)
+
+	wg1.Add(1)
+	wg2.Add(1)
+	go func() {
+		defer wg2.Done()
+		// Call service to encrypt data.
+		t.Log("Sending encrypt request")
+		wg1.Done()
+		_, err := service.Encrypt(ctx, uid, data)
+		if err != nil {
+			encryptErr = fmt.Errorf("failed when executing encrypt, error: %v", err)
+		}
+	}()
+
+	wg1.Wait()
+	time.Sleep(blackOut)
+	// Start KMS Plugin
+	f, err = mock.NewBase64Plugin(endpoint.path)
+	if err != nil {
+		t.Fatalf("failed to start test KMS provider server, error: %v", err)
+	}
+	if err := f.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer f.CleanUp()
+	t.Log("Restarted KMS Plugin")
+
+	wg2.Wait()
+
+	if encryptErr != nil {
+		t.Error(encryptErr)
+	}
+}
+
+// Normal encryption and decryption operation.
+func TestGRPCService(t *testing.T) {
+	t.Parallel()
+	// Start a test gRPC server.
+	endpoint := newEndpoint()
+	f, err := mock.NewBase64Plugin(endpoint.path)
+	if err != nil {
+		t.Fatalf("failed to construct test KMS provider server, error: %v", err)
+	}
+	if err := f.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer f.CleanUp()
+
+	// Create the gRPC client service.
+	service, err := NewGRPCService(endpoint.endpoint, 1*time.Second)
+	if err != nil {
+		t.Fatalf("failed to create envelope service, error: %v", err)
+	}
+	defer destroyService(service)
+
+	ctx := context.Background()
+	// Call service to encrypt data.
+	data := []byte("test data")
+	uid := string(uuid.NewUUID())
+	resp, err := service.Encrypt(ctx, uid, data)
+	if err != nil {
+		t.Fatalf("failed when execute encrypt, error: %v", err)
+	}
+
+	keyID := "1"
+	// Call service to decrypt data.
+	result, err := service.Decrypt(ctx, uid, &DecryptRequest{Ciphertext: resp.Ciphertext, KeyID: keyID})
+	if err != nil {
+		t.Fatalf("failed when execute decrypt, error: %v", err)
+	}
+
+	if !reflect.DeepEqual(data, result) {
+		t.Errorf("expect: %v, but: %v", data, result)
+	}
+}
+
+// Normal encryption and decryption operation by multiple go-routines.
+func TestGRPCServiceConcurrentAccess(t *testing.T) {
+	t.Parallel()
+	// Start a test gRPC server.
+	endpoint := newEndpoint()
+	f, err := mock.NewBase64Plugin(endpoint.path)
+	if err != nil {
+		t.Fatalf("failed to start test KMS provider server, error: %v", err)
+	}
+	if err := f.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer f.CleanUp()
+
+	// Create the gRPC client service.
+	service, err := NewGRPCService(endpoint.endpoint, 15*time.Second)
+	if err != nil {
+		t.Fatalf("failed to create envelope service, error: %v", err)
+	}
+	defer destroyService(service)
+
+	ctx := context.Background()
+	var wg sync.WaitGroup
+	n := 100
+	wg.Add(n)
+	for i := 0; i < n; i++ {
+		go func() {
+			defer wg.Done()
+			// Call service to encrypt data.
+			data := []byte("test data")
+			uid := string(uuid.NewUUID())
+			resp, err := service.Encrypt(ctx, uid, data)
+			if err != nil {
+				t.Errorf("failed when execute encrypt, error: %v", err)
+			}
+
+			keyID := "1"
+			// Call service to decrypt data.
+			result, err := service.Decrypt(ctx, uid, &DecryptRequest{Ciphertext: resp.Ciphertext, KeyID: keyID})
+			if err != nil {
+				t.Errorf("failed when execute decrypt, error: %v", err)
+			}
+
+			if !reflect.DeepEqual(data, result) {
+				t.Errorf("expect: %v, but: %v", data, result)
+			}
+		}()
+	}
+
+	wg.Wait()
+}
+
+func destroyService(service Service) {
+	if service != nil {
+		s := service.(*gRPCService)
+		s.connection.Close()
+	}
+}
+
+// Test all those invalid configuration for KMS provider.
+func TestInvalidConfiguration(t *testing.T) {
+	t.Parallel()
+	// Start a test gRPC server.
+	f, err := mock.NewBase64Plugin(newEndpoint().path)
+	if err != nil {
+		t.Fatalf("failed to start test KMS provider server, error: %v", err)
+	}
+	if err := f.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer f.CleanUp()
+
+	invalidConfigs := []struct {
+		name     string
+		endpoint string
+	}{
+		{"emptyConfiguration", ""},
+		{"invalidScheme", "tcp://localhost:6060"},
+	}
+
+	for _, testCase := range invalidConfigs {
+		t.Run(testCase.name, func(t *testing.T) {
+			_, err := NewGRPCService(testCase.endpoint, 1*time.Second)
+			if err == nil {
+				t.Fatalf("should fail to create envelope service for %s.", testCase.name)
+			}
+		})
+	}
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1/OWNERS

@@ -0,0 +1,9 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+# Disable inheritance as this is an api owners file
+options:
+  no_parent_owners: true
+approvers:
+  - api-approvers
+reviewers:
+  - sig-auth-api-reviewers

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1/api.pb.go

@@ -0,0 +1,128 @@
+/*
+Copyright The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Code generated by protoc-gen-gogo. DO NOT EDIT.
+// source: api.proto
+
+package v2alpha1
+
+import (
+	fmt "fmt"
+	proto "github.com/gogo/protobuf/proto"
+	math "math"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+// A compilation error at this line likely means your copy of the
+// proto package needs to be updated.
+const _ = proto.GoGoProtoPackageIsVersion3 // please upgrade the proto package
+
+// EncryptedObject is the representation of data stored in etcd after envelope encryption.
+type EncryptedObject struct {
+	// EncryptedData is the encrypted data.
+	EncryptedData []byte `protobuf:"bytes,1,opt,name=encryptedData,proto3" json:"encryptedData,omitempty"`
+	// KeyID is the KMS key ID used for encryption operations.
+	KeyID string `protobuf:"bytes,2,opt,name=keyID,proto3" json:"keyID,omitempty"`
+	// EncryptedDEK is the encrypted DEK.
+	EncryptedDEK []byte `protobuf:"bytes,3,opt,name=encryptedDEK,proto3" json:"encryptedDEK,omitempty"`
+	// Annotations is additional metadata that was provided by the KMS plugin.
+	Annotations          map[string][]byte `protobuf:"bytes,4,rep,name=annotations,proto3" json:"annotations,omitempty" protobuf_key:"bytes,1,opt,name=key,proto3" protobuf_val:"bytes,2,opt,name=value,proto3"`
+	XXX_NoUnkeyedLiteral struct{}          `json:"-"`
+	XXX_unrecognized     []byte            `json:"-"`
+	XXX_sizecache        int32             `json:"-"`
+}
+
+func (m *EncryptedObject) Reset()         { *m = EncryptedObject{} }
+func (m *EncryptedObject) String() string { return proto.CompactTextString(m) }
+func (*EncryptedObject) ProtoMessage()    {}
+func (*EncryptedObject) Descriptor() ([]byte, []int) {
+	return fileDescriptor_00212fb1f9d3bf1c, []int{0}
+}
+func (m *EncryptedObject) XXX_Unmarshal(b []byte) error {
+	return xxx_messageInfo_EncryptedObject.Unmarshal(m, b)
+}
+func (m *EncryptedObject) XXX_Marshal(b []byte, deterministic bool) ([]byte, error) {
+	return xxx_messageInfo_EncryptedObject.Marshal(b, m, deterministic)
+}
+func (m *EncryptedObject) XXX_Merge(src proto.Message) {
+	xxx_messageInfo_EncryptedObject.Merge(m, src)
+}
+func (m *EncryptedObject) XXX_Size() int {
+	return xxx_messageInfo_EncryptedObject.Size(m)
+}
+func (m *EncryptedObject) XXX_DiscardUnknown() {
+	xxx_messageInfo_EncryptedObject.DiscardUnknown(m)
+}
+
+var xxx_messageInfo_EncryptedObject proto.InternalMessageInfo
+
+func (m *EncryptedObject) GetEncryptedData() []byte {
+	if m != nil {
+		return m.EncryptedData
+	}
+	return nil
+}
+
+func (m *EncryptedObject) GetKeyID() string {
+	if m != nil {
+		return m.KeyID
+	}
+	return ""
+}
+
+func (m *EncryptedObject) GetEncryptedDEK() []byte {
+	if m != nil {
+		return m.EncryptedDEK
+	}
+	return nil
+}
+
+func (m *EncryptedObject) GetAnnotations() map[string][]byte {
+	if m != nil {
+		return m.Annotations
+	}
+	return nil
+}
+
+func init() {
+	proto.RegisterType((*EncryptedObject)(nil), "v2alpha1.EncryptedObject")
+	proto.RegisterMapType((map[string][]byte)(nil), "v2alpha1.EncryptedObject.AnnotationsEntry")
+}
+
+func init() { proto.RegisterFile("api.proto", fileDescriptor_00212fb1f9d3bf1c) }
+
+var fileDescriptor_00212fb1f9d3bf1c = []byte{
+	// 200 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0xff, 0xe2, 0xe2, 0x4c, 0x2c, 0xc8, 0xd4,
+	0x2b, 0x28, 0xca, 0x2f, 0xc9, 0x17, 0xe2, 0x28, 0x33, 0x4a, 0xcc, 0x29, 0xc8, 0x48, 0x34, 0x54,
+	0xfa, 0xcf, 0xc8, 0xc5, 0xef, 0x9a, 0x97, 0x5c, 0x54, 0x59, 0x50, 0x92, 0x9a, 0xe2, 0x9f, 0x94,
+	0x95, 0x9a, 0x5c, 0x22, 0xa4, 0xc2, 0xc5, 0x9b, 0x0a, 0x13, 0x72, 0x49, 0x2c, 0x49, 0x94, 0x60,
+	0x54, 0x60, 0xd4, 0xe0, 0x09, 0x42, 0x15, 0x14, 0x12, 0xe1, 0x62, 0xcd, 0x4e, 0xad, 0xf4, 0x74,
+	0x91, 0x60, 0x52, 0x60, 0xd4, 0xe0, 0x0c, 0x82, 0x70, 0x84, 0x94, 0xb8, 0x78, 0x10, 0xca, 0x5c,
+	0xbd, 0x25, 0x98, 0xc1, 0x5a, 0x51, 0xc4, 0x84, 0x7c, 0xb8, 0xb8, 0x13, 0xf3, 0xf2, 0xf2, 0x4b,
+	0x12, 0x4b, 0x32, 0xf3, 0xf3, 0x8a, 0x25, 0x58, 0x14, 0x98, 0x35, 0xb8, 0x8d, 0xb4, 0xf4, 0x60,
+	0x6e, 0xd2, 0x43, 0x73, 0x8f, 0x9e, 0x23, 0x42, 0xb1, 0x6b, 0x5e, 0x49, 0x51, 0x65, 0x10, 0xb2,
+	0x76, 0x29, 0x3b, 0x2e, 0x01, 0x74, 0x05, 0x42, 0x02, 0x5c, 0xcc, 0xd9, 0xa9, 0x95, 0x60, 0x77,
+	0x73, 0x06, 0x81, 0x98, 0x20, 0xd7, 0x96, 0x25, 0xe6, 0x94, 0xa6, 0x82, 0x5d, 0xcb, 0x13, 0x04,
+	0xe1, 0x58, 0x31, 0x59, 0x30, 0x26, 0xb1, 0x81, 0x83, 0xc4, 0x18, 0x10, 0x00, 0x00, 0xff, 0xff,
+	0x88, 0x8c, 0xbb, 0x4e, 0x1f, 0x01, 0x00, 0x00,
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1/api.proto

@@ -0,0 +1,35 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// To regenerate api.pb.go run hack/update-generated-kms.sh
+syntax = "proto3";
+
+package v2alpha1;
+
+// EncryptedObject is the representation of data stored in etcd after envelope encryption.
+message EncryptedObject {
+  // EncryptedData is the encrypted data.
+  bytes encryptedData = 1;
+
+  // KeyID is the KMS key ID used for encryption operations.
+  string keyID = 2;
+
+  // EncryptedDEK is the encrypted DEK.
+  bytes encryptedDEK = 3;
+
+  // Annotations is additional metadata that was provided by the KMS plugin.
+  map<string, bytes> annotations = 4;
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1/v2alpha1.go

@@ -0,0 +1,18 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package v2alpha1 contains definition of kms-plugin's serialized types.
+package v2alpha1

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/metrics/metrics.go

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package envelope
+package metrics
 
 import (
 	"sync"
@@ -27,8 +27,8 @@ import (
 const (
 	namespace        = "apiserver"
 	subsystem        = "envelope_encryption"
-	fromStorageLabel = "from_storage"
+	FromStorageLabel = "from_storage"
-	toStorageLabel   = "to_storage"
+	ToStorageLabel   = "to_storage"
 )
 
 /*
@@ -71,16 +71,16 @@ var (
 
 var registerMetricsFunc sync.Once
 
-func registerMetrics() {
+func RegisterMetrics() {
 	registerMetricsFunc.Do(func() {
 		legacyregistry.MustRegister(dekCacheFillPercent)
 		legacyregistry.MustRegister(dekCacheInterArrivals)
 	})
 }
 
-func recordArrival(transformationType string, start time.Time) {
+func RecordArrival(transformationType string, start time.Time) {
 	switch transformationType {
-	case fromStorageLabel:
+	case FromStorageLabel:
 		lockLastFromStorage.Lock()
 		defer lockLastFromStorage.Unlock()
 
@@ -89,7 +89,7 @@ func recordArrival(transformationType string, start time.Time) {
 		}
 		dekCacheInterArrivals.WithLabelValues(transformationType).Observe(start.Sub(lastFromStorage).Seconds())
 		lastFromStorage = start
-	case toStorageLabel:
+	case ToStorageLabel:
 		lockLastToStorage.Lock()
 		defer lockLastToStorage.Unlock()
 
@@ -100,3 +100,7 @@ func recordArrival(transformationType string, start time.Time) {
 		lastToStorage = start
 	}
 }
+
+func RecordDekCacheFillPercent(percent float64) {
+	dekCacheFillPercent.Set(percent)
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1/kms_plugin_mock.go

@@ -17,7 +17,7 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package testing
+package v1beta1
 
 import (
 	"context"

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v2alpha1/kms_plugin_mock.go

@@ -0,0 +1,191 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v2alpha1
+
+import (
+	"context"
+	"encoding/base64"
+	"fmt"
+	"net"
+	"os"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+
+	"k8s.io/apimachinery/pkg/util/wait"
+	kmsapi "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v2alpha1"
+	"k8s.io/klog/v2"
+)
+
+const (
+	// Now only supported unix domain socket.
+	unixProtocol = "unix"
+
+	// Current version for the protocol interface definition.
+	kmsapiVersion = "v2alpha1"
+)
+
+// Base64Plugin gRPC sever for a mock KMS provider.
+// Uses base64 to simulate encrypt and decrypt.
+type Base64Plugin struct {
+	grpcServer         *grpc.Server
+	listener           net.Listener
+	mu                 *sync.Mutex
+	lastEncryptRequest *kmsapi.EncryptRequest
+	inFailedState      bool
+	ver                string
+	socketPath         string
+}
+
+// NewBase64Plugin is a constructor for Base64Plugin.
+func NewBase64Plugin(socketPath string) (*Base64Plugin, error) {
+	server := grpc.NewServer()
+	result := &Base64Plugin{
+		grpcServer: server,
+		mu:         &sync.Mutex{},
+		ver:        kmsapiVersion,
+		socketPath: socketPath,
+	}
+
+	kmsapi.RegisterKeyManagementServiceServer(server, result)
+	return result, nil
+}
+
+// WaitForBase64PluginToBeUp waits until the plugin is ready to serve requests.
+func WaitForBase64PluginToBeUp(plugin *Base64Plugin) error {
+	var gRPCErr error
+	var resp *kmsapi.StatusResponse
+	pollErr := wait.PollImmediate(1*time.Second, wait.ForeverTestTimeout, func() (bool, error) {
+		resp, gRPCErr = plugin.Status(context.Background(), &kmsapi.StatusRequest{})
+		return gRPCErr == nil && resp.Healthz == "ok", nil
+	})
+
+	if pollErr == wait.ErrWaitTimeout {
+		return fmt.Errorf("failed to start kms-plugin, error: %v", gRPCErr)
+	}
+
+	return nil
+}
+
+// LastEncryptRequest returns the last EncryptRequest.Plain sent to the plugin.
+func (s *Base64Plugin) LastEncryptRequest() []byte {
+	return s.lastEncryptRequest.Plaintext
+}
+
+// SetVersion sets the version of kms-plugin.
+func (s *Base64Plugin) SetVersion(ver string) {
+	s.ver = ver
+}
+
+// Start starts plugin's gRPC service.
+func (s *Base64Plugin) Start() error {
+	var err error
+	s.listener, err = net.Listen(unixProtocol, s.socketPath)
+	if err != nil {
+		return fmt.Errorf("failed to listen on the unix socket, error: %v", err)
+	}
+	klog.Infof("Listening on %s", s.socketPath)
+
+	go s.grpcServer.Serve(s.listener)
+	return nil
+}
+
+// CleanUp stops gRPC server and the underlying listener.
+func (s *Base64Plugin) CleanUp() {
+	s.grpcServer.Stop()
+	s.listener.Close()
+	if !strings.HasPrefix(s.socketPath, "@") || runtime.GOOS != "linux" {
+		os.Remove(s.socketPath)
+	}
+}
+
+// EnterFailedState places the plugin into failed state.
+func (s *Base64Plugin) EnterFailedState() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.inFailedState = true
+}
+
+// ExitFailedState removes the plugin from the failed state.
+func (s *Base64Plugin) ExitFailedState() {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.inFailedState = false
+}
+
+// Status returns the status of the kms-plugin.
+func (s *Base64Plugin) Status(ctx context.Context, request *kmsapi.StatusRequest) (*kmsapi.StatusResponse, error) {
+	klog.Infof("Received request for Status: %v", request)
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if s.inFailedState {
+		return nil, status.Error(codes.FailedPrecondition, "failed precondition - key disabled")
+	}
+
+	return &kmsapi.StatusResponse{Version: s.ver, Healthz: "ok", KeyId: "1"}, nil
+}
+
+// Decrypt performs base64 decoding of the payload of kms.DecryptRequest.
+func (s *Base64Plugin) Decrypt(ctx context.Context, request *kmsapi.DecryptRequest) (*kmsapi.DecryptResponse, error) {
+	klog.V(3).Infof("Received Decrypt Request for DEK: %s", string(request.Ciphertext))
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if s.inFailedState {
+		return nil, status.Error(codes.FailedPrecondition, "failed precondition - key disabled")
+	}
+	if len(request.Uid) == 0 {
+		return nil, status.Error(codes.InvalidArgument, "uid is required")
+	}
+
+	buf := make([]byte, base64.StdEncoding.DecodedLen(len(request.Ciphertext)))
+	n, err := base64.StdEncoding.Decode(buf, request.Ciphertext)
+	if err != nil {
+		return nil, err
+	}
+
+	return &kmsapi.DecryptResponse{Plaintext: buf[:n]}, nil
+}
+
+// Encrypt performs base64 encoding of the payload of kms.EncryptRequest.
+func (s *Base64Plugin) Encrypt(ctx context.Context, request *kmsapi.EncryptRequest) (*kmsapi.EncryptResponse, error) {
+	klog.V(3).Infof("Received Encrypt Request for DEK: %x", request.Plaintext)
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	s.lastEncryptRequest = request
+
+	if s.inFailedState {
+		return nil, status.Error(codes.FailedPrecondition, "failed precondition - key disabled")
+	}
+	if len(request.Uid) == 0 {
+		return nil, status.Error(codes.InvalidArgument, "uid is required")
+	}
+
+	buf := make([]byte, base64.StdEncoding.EncodedLen(len(request.Plaintext)))
+	base64.StdEncoding.Encode(buf, request.Plaintext)
+
+	return &kmsapi.EncryptResponse{Ciphertext: buf, KeyId: "1", Annotations: map[string][]byte{"kms.kubernetes.io/local-kek": []byte("encrypted-local-kek")}}, nil
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/util/util.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+const (
+	// unixProtocol is the only supported protocol for remote KMS provider.
+	unixProtocol = "unix"
+)
+
+// Parse the endpoint to extract schema, host or path.
+func ParseEndpoint(endpoint string) (string, error) {
+	if len(endpoint) == 0 {
+		return "", fmt.Errorf("remote KMS provider can't use empty string as endpoint")
+	}
+
+	u, err := url.Parse(endpoint)
+	if err != nil {
+		return "", fmt.Errorf("invalid endpoint %q for remote KMS provider, error: %v", endpoint, err)
+	}
+
+	if u.Scheme != unixProtocol {
+		return "", fmt.Errorf("unsupported scheme %q for remote KMS provider", u.Scheme)
+	}
+
+	// Linux abstract namespace socket - no physical file required
+	// Warning: Linux Abstract sockets have not concept of ACL (unlike traditional file based sockets).
+	// However, Linux Abstract sockets are subject to Linux networking namespace, so will only be accessible to
+	// containers within the same pod (unless host networking is used).
+	if strings.HasPrefix(u.Path, "/@") {
+		return strings.TrimPrefix(u.Path, "/"), nil
+	}
+
+	return u.Path, nil
+}

staging/src/k8s.io/apiserver/pkg/storage/value/encrypt/envelope/util/util_test.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestParseEndpoint(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		endpoint string
+		want     string
+	}{
+		{
+			desc:     "path with prefix",
+			endpoint: "unix:///@path",
+			want:     "@path",
+		},
+		{
+			desc:     "path without prefix",
+			endpoint: "unix:///path",
+			want:     "/path",
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			got, err := ParseEndpoint(tt.endpoint)
+			if err != nil {
+				t.Errorf("ParseEndpoint(%q) error: %v", tt.endpoint, err)
+			}
+			if got != tt.want {
+				t.Errorf("ParseEndpoint(%q) = %q, want %q", tt.endpoint, got, tt.want)
+			}
+		})
+	}
+}
+
+func TestParseEndpointError(t *testing.T) {
+	testCases := []struct {
+		desc     string
+		endpoint string
+		wantErr  string
+	}{
+		{
+			desc:     "empty endpoint",
+			endpoint: "",
+			wantErr:  "remote KMS provider can't use empty string as endpoint",
+		},
+		{
+			desc:     "invalid scheme",
+			endpoint: "http:///path",
+			wantErr:  "unsupported scheme \"http\" for remote KMS provider",
+		},
+	}
+
+	for _, tt := range testCases {
+		t.Run(tt.desc, func(t *testing.T) {
+			_, err := ParseEndpoint(tt.endpoint)
+			if err == nil {
+				t.Errorf("ParseEndpoint(%q) error: %v", tt.endpoint, err)
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Errorf("ParseEndpoint(%q) = %q, want %q", tt.endpoint, err, tt.wantErr)
+			}
+		})
+	}
+}

test/integration/controlplane/transformation/kms_transformation_test.go

@@ -36,7 +36,7 @@ import (
 	"k8s.io/apimachinery/pkg/util/wait"
 	"k8s.io/apiserver/pkg/storage/value"
 	aestransformer "k8s.io/apiserver/pkg/storage/value/encrypt/aes"
-	mock "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing"
+	mock "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1"
 	kmsapi "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v1beta1"
 	"k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"

test/integration/controlplane/transformation/kmsv2_transformation_test.go

@@ -0,0 +1,275 @@
+//go:build !windows
+// +build !windows
+
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package transformation
+
+import (
+	"bytes"
+	"context"
+	"crypto/aes"
+	"fmt"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/gogo/protobuf/proto"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/types"
+	"k8s.io/apimachinery/pkg/util/uuid"
+	"k8s.io/apiserver/pkg/features"
+	"k8s.io/apiserver/pkg/storage/value"
+	aestransformer "k8s.io/apiserver/pkg/storage/value/encrypt/aes"
+	kmstypes "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1"
+	kmsv2mock "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v2alpha1"
+	kmsv2api "k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v2alpha1"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	featuregatetesting "k8s.io/component-base/featuregate/testing"
+)
+
+type envelopekmsv2 struct {
+	providerName string
+	rawEnvelope  []byte
+	plainTextDEK []byte
+}
+
+func (r envelopekmsv2) prefix() string {
+	return fmt.Sprintf("k8s:enc:kms:v2:%s:", r.providerName)
+}
+
+func (r envelopekmsv2) prefixLen() int {
+	return len(r.prefix())
+}
+
+func (r envelopekmsv2) cipherTextDEK() ([]byte, error) {
+	o := &kmstypes.EncryptedObject{}
+	if err := proto.Unmarshal(r.rawEnvelope[r.startOfPayload(r.providerName):], o); err != nil {
+		return nil, err
+	}
+	return o.EncryptedDEK, nil
+}
+
+func (r envelopekmsv2) startOfPayload(_ string) int {
+	return r.prefixLen()
+}
+
+func (r envelopekmsv2) cipherTextPayload() ([]byte, error) {
+	o := &kmstypes.EncryptedObject{}
+	if err := proto.Unmarshal(r.rawEnvelope[r.startOfPayload(r.providerName):], o); err != nil {
+		return nil, err
+	}
+	return o.EncryptedData, nil
+}
+
+func (r envelopekmsv2) plainTextPayload(secretETCDPath string) ([]byte, error) {
+	block, err := aes.NewCipher(r.plainTextDEK)
+	if err != nil {
+		return nil, fmt.Errorf("failed to initialize AES Cipher: %v", err)
+	}
+	ctx := context.Background()
+	dataCtx := value.DefaultContext([]byte(secretETCDPath))
+	aesgcmTransformer := aestransformer.NewGCMTransformer(block)
+	data, err := r.cipherTextPayload()
+	if err != nil {
+		return nil, fmt.Errorf("failed to get cipher text payload: %v", err)
+	}
+	plainSecret, _, err := aesgcmTransformer.TransformFromStorage(ctx, data, dataCtx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to transform from storage via AESGCM, err: %w", err)
+	}
+
+	return plainSecret, nil
+}
+
+// TestKMSv2Provider is an integration test between KubeAPI, ETCD and KMSv2 Plugin
+// Concretely, this test verifies the following integration contracts:
+// 1. Raw records in ETCD that were processed by KMSv2 Provider should be prefixed with []byte{'e', 'k', '8', 's', 0}
+// 2. Data Encryption Key (DEK) should be generated by envelopeTransformer and passed to KMS gRPC Plugin
+// 3. KMS gRPC Plugin should encrypt the DEK with a Key Encryption Key (KEK) and pass it back to envelopeTransformer
+// 4. The cipherTextPayload (ex. Secret) should be encrypted via AES GCM transform
+// 5. kmstypes.EncryptedObject structure should be serialized and deposited in ETCD
+func TestKMSv2Provider(t *testing.T) {
+	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.KMSv2, true)()
+
+	encryptionConfig := `
+kind: EncryptionConfiguration
+apiVersion: apiserver.config.k8s.io/v1
+resources:
+  - resources:
+    - secrets
+    providers:
+    - kms:
+       apiVersion: v2
+       name: kms-provider
+       cachesize: 1000
+       endpoint: unix:///@kms-provider.sock
+`
+
+	providerName := "kms-provider"
+	pluginMock, err := kmsv2mock.NewBase64Plugin("@kms-provider.sock")
+	if err != nil {
+		t.Fatalf("failed to create mock of KMSv2 Plugin: %v", err)
+	}
+
+	go pluginMock.Start()
+	if err := kmsv2mock.WaitForBase64PluginToBeUp(pluginMock); err != nil {
+		t.Fatalf("Failed start plugin, err: %v", err)
+	}
+	defer pluginMock.CleanUp()
+
+	test, err := newTransformTest(t, encryptionConfig)
+	if err != nil {
+		t.Fatalf("failed to start KUBE API Server with encryptionConfig\n %s, error: %v", encryptionConfig, err)
+	}
+	defer test.cleanUp()
+
+	test.secret, err = test.createSecret(testSecret, testNamespace)
+	if err != nil {
+		t.Fatalf("Failed to create test secret, error: %v", err)
+	}
+
+	// Since Data Encryption Key (DEK) is randomly generated (per encryption operation), we need to ask KMS Mock for it.
+	plainTextDEK := pluginMock.LastEncryptRequest()
+
+	secretETCDPath := test.getETCDPath()
+	rawEnvelope, err := test.getRawSecretFromETCD()
+	if err != nil {
+		t.Fatalf("failed to read %s from etcd: %v", secretETCDPath, err)
+	}
+
+	envelopeData := envelopekmsv2{
+		providerName: providerName,
+		rawEnvelope:  rawEnvelope,
+		plainTextDEK: plainTextDEK,
+	}
+
+	wantPrefix := string(envelopeData.prefix())
+	if !bytes.HasPrefix(rawEnvelope, []byte(wantPrefix)) {
+		t.Fatalf("expected secret to be prefixed with %s, but got %s", wantPrefix, rawEnvelope)
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	ciphertext, err := envelopeData.cipherTextDEK()
+	if err != nil {
+		t.Fatalf("failed to get ciphertext DEK from KMSv2 Plugin: %v", err)
+	}
+	decryptResponse, err := pluginMock.Decrypt(ctx, &kmsv2api.DecryptRequest{Uid: string(types.UID(uuid.NewUUID())), Ciphertext: ciphertext})
+	if err != nil {
+		t.Fatalf("failed to decrypt DEK, %v", err)
+	}
+	dekPlainAsWouldBeSeenByETCD := decryptResponse.Plaintext
+
+	if !bytes.Equal(plainTextDEK, dekPlainAsWouldBeSeenByETCD) {
+		t.Fatalf("expected plainTextDEK %v to be passed to KMS Plugin, but got %s",
+			plainTextDEK, dekPlainAsWouldBeSeenByETCD)
+	}
+
+	plainSecret, err := envelopeData.plainTextPayload(secretETCDPath)
+	if err != nil {
+		t.Fatalf("failed to transform from storage via AESGCM, err: %v", err)
+	}
+
+	if !strings.Contains(string(plainSecret), secretVal) {
+		t.Fatalf("expected %q after decryption, but got %q", secretVal, string(plainSecret))
+	}
+
+	secretClient := test.restClient.CoreV1().Secrets(testNamespace)
+	// Secrets should be un-enveloped on direct reads from Kube API Server.
+	s, err := secretClient.Get(ctx, testSecret, metav1.GetOptions{})
+	if err != nil {
+		t.Fatalf("failed to get Secret from %s, err: %v", testNamespace, err)
+	}
+	if secretVal != string(s.Data[secretKey]) {
+		t.Fatalf("expected %s from KubeAPI, but got %s", secretVal, string(s.Data[secretKey]))
+	}
+}
+
+func TestKMSv2Healthz(t *testing.T) {
+	defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.KMSv2, true)()
+
+	encryptionConfig := `
+kind: EncryptionConfiguration
+apiVersion: apiserver.config.k8s.io/v1
+resources:
+  - resources:
+    - secrets
+    providers:
+    - kms:
+       apiVersion: v2
+       name: provider-1
+       endpoint: unix:///@kms-provider-1.sock
+    - kms:
+       apiVersion: v2
+       name: provider-2
+       endpoint: unix:///@kms-provider-2.sock
+`
+
+	pluginMock1, err := kmsv2mock.NewBase64Plugin("@kms-provider-1.sock")
+	if err != nil {
+		t.Fatalf("failed to create mock of KMS Plugin #1: %v", err)
+	}
+
+	if err := pluginMock1.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer pluginMock1.CleanUp()
+	if err := kmsv2mock.WaitForBase64PluginToBeUp(pluginMock1); err != nil {
+		t.Fatalf("Failed to start plugin #1, err: %v", err)
+	}
+
+	pluginMock2, err := kmsv2mock.NewBase64Plugin("@kms-provider-2.sock")
+	if err != nil {
+		t.Fatalf("Failed to create mock of KMS Plugin #2: err: %v", err)
+	}
+	if err := pluginMock2.Start(); err != nil {
+		t.Fatalf("Failed to start kms-plugin, err: %v", err)
+	}
+	defer pluginMock2.CleanUp()
+	if err := kmsv2mock.WaitForBase64PluginToBeUp(pluginMock2); err != nil {
+		t.Fatalf("Failed to start KMS Plugin #2: err: %v", err)
+	}
+
+	test, err := newTransformTest(t, encryptionConfig)
+	if err != nil {
+		t.Fatalf("Failed to start kube-apiserver, error: %v", err)
+	}
+	defer test.cleanUp()
+
+	// Name of the healthz check is calculated based on a constant "kms-provider-" + position of the
+	// provider in the config.
+
+	// Stage 1 - Since all kms-plugins are guaranteed to be up, healthz checks for:
+	// healthz/kms-provider-0 and /healthz/kms-provider-1 should be OK.
+	mustBeHealthy(t, "kms-provider-0", test.kubeAPIServer.ClientConfig)
+	mustBeHealthy(t, "kms-provider-1", test.kubeAPIServer.ClientConfig)
+
+	// Stage 2 - kms-plugin for provider-1 is down. Therefore, expect the health check for provider-1
+	// to fail, but provider-2 should still be OK
+	pluginMock1.EnterFailedState()
+	mustBeUnHealthy(t, "kms-provider-0", test.kubeAPIServer.ClientConfig)
+	mustBeHealthy(t, "kms-provider-1", test.kubeAPIServer.ClientConfig)
+	pluginMock1.ExitFailedState()
+
+	// Stage 3 - kms-plugin for provider-1 is now up. Therefore, expect the health check for provider-1
+	// to succeed now, but provider-2 is now down.
+	// Need to sleep since health check chases responses for 3 seconds.
+	pluginMock2.EnterFailedState()
+	mustBeHealthy(t, "kms-provider-0", test.kubeAPIServer.ClientConfig)
+	mustBeUnHealthy(t, "kms-provider-1", test.kubeAPIServer.ClientConfig)
+}

test/integration/framework/etcd.go

@@ -198,7 +198,7 @@ func EtcdMain(tests func() int) {
 		// like k8s.io/klog/v2.(*loggingT).flushDaemon()
 		// TODO(#108483): Reduce this number once we address the
 		//   couple remaining issues.
-		if dg := runtime.NumGoroutine() - before; dg <= 10 {
+		if dg := runtime.NumGoroutine() - before; dg <= 15 {
 			return true, nil
 		}
 		// Allow goroutines to schedule and die off.

vendor/modules.txt

@@ -1648,8 +1648,14 @@ k8s.io/apiserver/pkg/storage/testing
 k8s.io/apiserver/pkg/storage/value
 k8s.io/apiserver/pkg/storage/value/encrypt/aes
 k8s.io/apiserver/pkg/storage/value/encrypt/envelope
-k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/kmsv2/v2alpha1
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/metrics
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v1beta1
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/testing/v2alpha1
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/util
 k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v1beta1
+k8s.io/apiserver/pkg/storage/value/encrypt/envelope/v2alpha1
 k8s.io/apiserver/pkg/storage/value/encrypt/identity
 k8s.io/apiserver/pkg/storage/value/encrypt/secretbox
 k8s.io/apiserver/pkg/storageversion