diff --git a/pkg/app/piped/cloudprovider/lambda/BUILD.bazel b/pkg/app/piped/cloudprovider/lambda/BUILD.bazel
index 886e104372..9c35e42146 100644
--- a/pkg/app/piped/cloudprovider/lambda/BUILD.bazel
+++ b/pkg/app/piped/cloudprovider/lambda/BUILD.bazel
@@ -35,6 +35,7 @@ go_test(
     ],
     embed = [":go_default_library"],
     deps = [
+        "//pkg/model:go_default_library",
         "@com_github_stretchr_testify//assert:go_default_library",
     ],
 )
diff --git a/pkg/app/piped/controller/scheduler.go b/pkg/app/piped/controller/scheduler.go
index 32e4e77fb1..1a7ba4fa0f 100644
--- a/pkg/app/piped/controller/scheduler.go
+++ b/pkg/app/piped/controller/scheduler.go
@@ -434,7 +434,7 @@ func (s *scheduler) executeStage(sig executor.StopSignal, ps model.PipelineStage
 	}
 
 	// Check the existence of the specified cloud provider.
-	if !s.pipedConfig.HasCloudProvider(s.deployment.CloudProvider, s.deployment.CloudProviderType()) {
+	if !s.pipedConfig.HasCloudProvider(s.deployment.CloudProvider, s.deployment.Kind) {
 		lp.Errorf("This piped is not having the specified cloud provider in this deployment: %v", s.deployment.CloudProvider)
 		if err := s.reportStageStatus(ctx, ps.Id, model.StageStatus_STAGE_FAILURE, ps.Requires); err != nil {
 			s.logger.Error("failed to report stage status", zap.Error(err))
diff --git a/pkg/app/piped/driftdetector/detector.go b/pkg/app/piped/driftdetector/detector.go
index 1fd204ccae..01d5f7aae5 100644
--- a/pkg/app/piped/driftdetector/detector.go
+++ b/pkg/app/piped/driftdetector/detector.go
@@ -96,7 +96,7 @@ func NewDetector(
 
 	for _, cp := range cfg.CloudProviders {
 		switch cp.Type {
-		case model.CloudProviderKubernetes:
+		case model.ApplicationKind_KUBERNETES:
 			sg, ok := stateGetter.KubernetesGetter(cp.Name)
 			if !ok {
 				return nil, fmt.Errorf(format, cp.Name)
@@ -113,7 +113,7 @@ func NewDetector(
 				logger,
 			))
 
-		case model.CloudProviderCloudRun:
+		case model.ApplicationKind_CLOUDRUN:
 			sg, ok := stateGetter.CloudRunGetter(cp.Name)
 			if !ok {
 				return nil, fmt.Errorf(format, cp.Name)
diff --git a/pkg/app/piped/executor/cloudrun/cloudrun.go b/pkg/app/piped/executor/cloudrun/cloudrun.go
index ba1cc06d1a..5c279685e1 100644
--- a/pkg/app/piped/executor/cloudrun/cloudrun.go
+++ b/pkg/app/piped/executor/cloudrun/cloudrun.go
@@ -65,7 +65,7 @@ func findCloudProvider(in *executor.Input) (name string, cfg *config.CloudProvid
 		return
 	}
 
-	cp, ok := in.PipedConfig.FindCloudProvider(name, model.CloudProviderCloudRun)
+	cp, ok := in.PipedConfig.FindCloudProvider(name, model.ApplicationKind_CLOUDRUN)
 	if !ok {
 		in.LogPersister.Errorf("The specified cloud provider %q was not found in piped configuration", name)
 		return
diff --git a/pkg/app/piped/executor/ecs/ecs.go b/pkg/app/piped/executor/ecs/ecs.go
index 29ad75c008..e742cc6159 100644
--- a/pkg/app/piped/executor/ecs/ecs.go
+++ b/pkg/app/piped/executor/ecs/ecs.go
@@ -73,7 +73,7 @@ func findCloudProvider(in *executor.Input) (name string, cfg *config.CloudProvid
 		return
 	}
 
-	cp, ok := in.PipedConfig.FindCloudProvider(name, model.CloudProviderECS)
+	cp, ok := in.PipedConfig.FindCloudProvider(name, model.ApplicationKind_ECS)
 	if !ok {
 		in.LogPersister.Errorf("The specified cloud provider %q was not found in piped configuration", name)
 		return
diff --git a/pkg/app/piped/executor/lambda/lambda.go b/pkg/app/piped/executor/lambda/lambda.go
index 96c64a363c..2dc1e3fba3 100644
--- a/pkg/app/piped/executor/lambda/lambda.go
+++ b/pkg/app/piped/executor/lambda/lambda.go
@@ -62,7 +62,7 @@ func findCloudProvider(in *executor.Input) (name string, cfg *config.CloudProvid
 		return
 	}
 
-	cp, ok := in.PipedConfig.FindCloudProvider(name, model.CloudProviderLambda)
+	cp, ok := in.PipedConfig.FindCloudProvider(name, model.ApplicationKind_LAMBDA)
 	if !ok {
 		in.LogPersister.Errorf("The specified cloud provider %q was not found in piped configuration", name)
 		return
diff --git a/pkg/app/piped/executor/terraform/terraform.go b/pkg/app/piped/executor/terraform/terraform.go
index ae2d80ebd4..b6aa914a9e 100644
--- a/pkg/app/piped/executor/terraform/terraform.go
+++ b/pkg/app/piped/executor/terraform/terraform.go
@@ -87,7 +87,7 @@ func findCloudProvider(in *executor.Input) (name string, cfg *config.CloudProvid
 		return
 	}
 
-	cp, ok := in.PipedConfig.FindCloudProvider(name, model.CloudProviderTerraform)
+	cp, ok := in.PipedConfig.FindCloudProvider(name, model.ApplicationKind_TERRAFORM)
 	if !ok {
 		in.LogPersister.Errorf("The specified cloud provider %q was not found in piped configuration", name)
 		return
diff --git a/pkg/app/piped/livestatereporter/reporter.go b/pkg/app/piped/livestatereporter/reporter.go
index bbb33c548f..cbac723a65 100644
--- a/pkg/app/piped/livestatereporter/reporter.go
+++ b/pkg/app/piped/livestatereporter/reporter.go
@@ -65,14 +65,14 @@ func NewReporter(appLister applicationLister, stateGetter livestatestore.Getter,
 	for _, cp := range cfg.CloudProviders {
 		errFmt := fmt.Sprintf("unable to find live state getter for cloud provider: %s", cp.Name)
 		switch cp.Type {
-		case model.CloudProviderKubernetes:
+		case model.ApplicationKind_KUBERNETES:
 			sg, ok := stateGetter.KubernetesGetter(cp.Name)
 			if !ok {
 				r.logger.Error(errFmt)
 				continue
 			}
 			r.reporters = append(r.reporters, kubernetes.NewReporter(cp, appLister, sg, apiClient, logger))
-		case model.CloudProviderCloudRun:
+		case model.ApplicationKind_CLOUDRUN:
 			sg, ok := stateGetter.CloudRunGetter(cp.Name)
 			if !ok {
 				r.logger.Error(errFmt)
diff --git a/pkg/app/piped/livestatestore/livestatestore.go b/pkg/app/piped/livestatestore/livestatestore.go
index 14bc2089e1..faf27b222c 100644
--- a/pkg/app/piped/livestatestore/livestatestore.go
+++ b/pkg/app/piped/livestatestore/livestatestore.go
@@ -105,15 +105,15 @@ func NewStore(ctx context.Context, cfg *config.PipedSpec, appLister applicationL
 	}
 	for _, cp := range cfg.CloudProviders {
 		switch cp.Type {
-		case model.CloudProviderKubernetes:
+		case model.ApplicationKind_KUBERNETES:
 			store := kubernetes.NewStore(cp.KubernetesConfig, cfg, cp.Name, logger)
 			s.kubernetesStores[cp.Name] = store
 
-		case model.CloudProviderTerraform:
+		case model.ApplicationKind_TERRAFORM:
 			store := terraform.NewStore(cp.TerraformConfig, cp.Name, appLister, logger)
 			s.terraformStores[cp.Name] = store
 
-		case model.CloudProviderCloudRun:
+		case model.ApplicationKind_CLOUDRUN:
 			store, err := cloudrun.NewStore(ctx, cp.CloudRunConfig, cp.Name, logger)
 			if err != nil {
 				logger.Error("failed to create a new cloudrun's livestatestore", zap.Error(err))
@@ -121,11 +121,11 @@ func NewStore(ctx context.Context, cfg *config.PipedSpec, appLister applicationL
 			}
 			s.cloudrunStores[cp.Name] = store
 
-		case model.CloudProviderLambda:
+		case model.ApplicationKind_LAMBDA:
 			store := lambda.NewStore(cp.LambdaConfig, cp.Name, appLister, logger)
 			s.lambdaStores[cp.Name] = store
 
-		case model.CloudProviderECS:
+		case model.ApplicationKind_ECS:
 			store := ecs.NewStore(cp.ECSConfig, cp.Name, appLister, logger)
 			s.ecsStores[cp.Name] = store
 		}
diff --git a/pkg/app/piped/planpreview/terraformdiff.go b/pkg/app/piped/planpreview/terraformdiff.go
index f83d6599a6..c440e7f33d 100644
--- a/pkg/app/piped/planpreview/terraformdiff.go
+++ b/pkg/app/piped/planpreview/terraformdiff.go
@@ -33,7 +33,7 @@ func (b *builder) terraformDiff(
 	buf *bytes.Buffer,
 ) (*diffResult, error) {
 
-	cp, ok := b.pipedCfg.FindCloudProvider(app.CloudProvider, model.CloudProviderTerraform)
+	cp, ok := b.pipedCfg.FindCloudProvider(app.CloudProvider, model.ApplicationKind_TERRAFORM)
 	if !ok {
 		err := fmt.Errorf("cloud provider %s was not found in Piped config", app.CloudProvider)
 		fmt.Fprintln(buf, err.Error())
diff --git a/pkg/config/piped.go b/pkg/config/piped.go
index de189ea209..8d51dd8d10 100644
--- a/pkg/config/piped.go
+++ b/pkg/config/piped.go
@@ -24,9 +24,9 @@ import (
 	"github.com/pipe-cd/pipecd/pkg/model"
 )
 
-var DefaultKubernetesCloudProvider = PipedCloudProvider{
+var defaultKubernetesCloudProvider = PipedCloudProvider{
 	Name:             "kubernetes-default",
-	Type:             model.CloudProviderKubernetes,
+	Type:             model.ApplicationKind_KUBERNETES,
 	KubernetesConfig: &CloudProviderKubernetesConfig{},
 }
 
@@ -116,15 +116,15 @@ func (s *PipedSpec) Validate() error {
 // EnableDefaultKubernetesCloudProvider adds the default kubernetes cloud provider if it was not specified.
 func (s *PipedSpec) EnableDefaultKubernetesCloudProvider() {
 	for _, cp := range s.CloudProviders {
-		if cp.Name == DefaultKubernetesCloudProvider.Name {
+		if cp.Name == defaultKubernetesCloudProvider.Name {
 			return
 		}
 	}
-	s.CloudProviders = append(s.CloudProviders, DefaultKubernetesCloudProvider)
+	s.CloudProviders = append(s.CloudProviders, defaultKubernetesCloudProvider)
 }
 
 // HasCloudProvider checks whether the given provider is configured or not.
-func (s *PipedSpec) HasCloudProvider(name string, t model.CloudProviderType) bool {
+func (s *PipedSpec) HasCloudProvider(name string, t model.ApplicationKind) bool {
 	for _, cp := range s.CloudProviders {
 		if cp.Name != name {
 			continue
@@ -138,7 +138,7 @@ func (s *PipedSpec) HasCloudProvider(name string, t model.CloudProviderType) boo
 }
 
 // FindCloudProvider finds and returns a Cloud Provider by name and type.
-func (s *PipedSpec) FindCloudProvider(name string, t model.CloudProviderType) (PipedCloudProvider, bool) {
+func (s *PipedSpec) FindCloudProvider(name string, t model.ApplicationKind) (PipedCloudProvider, bool) {
 	for _, p := range s.CloudProviders {
 		if p.Name != name {
 			continue
@@ -335,7 +335,7 @@ func (s *PipedSpec) GitHelmChartRepositories() []HelmChartRepository {
 
 type PipedCloudProvider struct {
 	Name string
-	Type model.CloudProviderType
+	Type model.ApplicationKind
 
 	KubernetesConfig *CloudProviderKubernetesConfig
 	TerraformConfig  *CloudProviderTerraformConfig
@@ -345,9 +345,9 @@ type PipedCloudProvider struct {
 }
 
 type genericPipedCloudProvider struct {
-	Name   string                  `json:"name"`
-	Type   model.CloudProviderType `json:"type"`
-	Config json.RawMessage         `json:"config"`
+	Name   string          `json:"name"`
+	Type   string          `json:"type"`
+	Config json.RawMessage `json:"config"`
 }
 
 func (p *PipedCloudProvider) UnmarshalJSON(data []byte) error {
@@ -357,30 +357,30 @@ func (p *PipedCloudProvider) UnmarshalJSON(data []byte) error {
 		return err
 	}
 	p.Name = gp.Name
-	p.Type = gp.Type
+	p.Type = model.ApplicationKind(model.ApplicationKind_value[gp.Type])
 
 	switch p.Type {
-	case model.CloudProviderKubernetes:
+	case model.ApplicationKind_KUBERNETES:
 		p.KubernetesConfig = &CloudProviderKubernetesConfig{}
 		if len(gp.Config) > 0 {
 			err = json.Unmarshal(gp.Config, p.KubernetesConfig)
 		}
-	case model.CloudProviderTerraform:
+	case model.ApplicationKind_TERRAFORM:
 		p.TerraformConfig = &CloudProviderTerraformConfig{}
 		if len(gp.Config) > 0 {
 			err = json.Unmarshal(gp.Config, p.TerraformConfig)
 		}
-	case model.CloudProviderCloudRun:
+	case model.ApplicationKind_CLOUDRUN:
 		p.CloudRunConfig = &CloudProviderCloudRunConfig{}
 		if len(gp.Config) > 0 {
 			err = json.Unmarshal(gp.Config, p.CloudRunConfig)
 		}
-	case model.CloudProviderLambda:
+	case model.ApplicationKind_LAMBDA:
 		p.LambdaConfig = &CloudProviderLambdaConfig{}
 		if len(gp.Config) > 0 {
 			err = json.Unmarshal(gp.Config, p.LambdaConfig)
 		}
-	case model.CloudProviderECS:
+	case model.ApplicationKind_ECS:
 		p.ECSConfig = &CloudProviderECSConfig{}
 		if len(gp.Config) > 0 {
 			err = json.Unmarshal(gp.Config, p.ECSConfig)
diff --git a/pkg/config/piped_test.go b/pkg/config/piped_test.go
index fb4f77bc62..c462c60044 100644
--- a/pkg/config/piped_test.go
+++ b/pkg/config/piped_test.go
@@ -79,7 +79,7 @@ func TestPipedConfig(t *testing.T) {
 				CloudProviders: []PipedCloudProvider{
 					{
 						Name: "kubernetes-default",
-						Type: model.CloudProviderKubernetes,
+						Type: model.ApplicationKind_KUBERNETES,
 						KubernetesConfig: &CloudProviderKubernetesConfig{
 							AppStateInformer: KubernetesAppStateInformer{
 								IncludeResources: []KubernetesResourceMatcher{
@@ -102,12 +102,12 @@ func TestPipedConfig(t *testing.T) {
 					},
 					{
 						Name:             "kubernetes-dev",
-						Type:             model.CloudProviderKubernetes,
+						Type:             model.ApplicationKind_KUBERNETES,
 						KubernetesConfig: &CloudProviderKubernetesConfig{},
 					},
 					{
 						Name: "terraform",
-						Type: model.CloudProviderTerraform,
+						Type: model.ApplicationKind_TERRAFORM,
 						TerraformConfig: &CloudProviderTerraformConfig{
 							Vars: []string{
 								"project=gcp-project",
@@ -117,7 +117,7 @@ func TestPipedConfig(t *testing.T) {
 					},
 					{
 						Name: "cloudrun",
-						Type: model.CloudProviderCloudRun,
+						Type: model.ApplicationKind_CLOUDRUN,
 						CloudRunConfig: &CloudProviderCloudRunConfig{
 							Project:         "gcp-project-id",
 							Region:          "cloud-run-region",
@@ -126,7 +126,7 @@ func TestPipedConfig(t *testing.T) {
 					},
 					{
 						Name: "lambda",
-						Type: model.CloudProviderLambda,
+						Type: model.ApplicationKind_LAMBDA,
 						LambdaConfig: &CloudProviderLambdaConfig{
 							Region: "us-east-1",
 						},
diff --git a/pkg/model/BUILD.bazel b/pkg/model/BUILD.bazel
index 73142aa61a..456fa90d0e 100644
--- a/pkg/model/BUILD.bazel
+++ b/pkg/model/BUILD.bazel
@@ -15,7 +15,6 @@ go_library(
         "application_live_state.go",
         "application_live_state.pb.go",
         "application_live_state.pb.validate.go",
-        "cloudprovider.go",
         "command.go",
         "command.pb.go",
         "command.pb.validate.go",
diff --git a/pkg/model/cloudprovider.go b/pkg/model/cloudprovider.go
deleted file mode 100644
index fae4f8008f..0000000000
--- a/pkg/model/cloudprovider.go
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright 2020 The PipeCD 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 model
-
-type CloudProviderType string
-
-const (
-	CloudProviderKubernetes CloudProviderType = "KUBERNETES"
-	CloudProviderTerraform  CloudProviderType = "TERRAFORM"
-	CloudProviderCloudRun   CloudProviderType = "CLOUDRUN"
-	CloudProviderLambda     CloudProviderType = "LAMBDA"
-	CloudProviderECS        CloudProviderType = "ECS"
-)
-
-func (t CloudProviderType) String() string {
-	return string(t)
-}
diff --git a/pkg/model/deployment.go b/pkg/model/deployment.go
index da086093b6..3761bdfa59 100644
--- a/pkg/model/deployment.go
+++ b/pkg/model/deployment.go
@@ -152,24 +152,6 @@ func (d *Deployment) TriggerBefore(other *Deployment) bool {
 
 }
 
-// CloudProviderType determines the cloud provider type from application kind.
-func (d *Deployment) CloudProviderType() CloudProviderType {
-	switch d.Kind {
-	case ApplicationKind_KUBERNETES:
-		return CloudProviderKubernetes
-	case ApplicationKind_TERRAFORM:
-		return CloudProviderTerraform
-	case ApplicationKind_CLOUDRUN:
-		return CloudProviderCloudRun
-	case ApplicationKind_LAMBDA:
-		return CloudProviderLambda
-	case ApplicationKind_ECS:
-		return CloudProviderECS
-	default:
-		return CloudProviderType(d.Kind.String())
-	}
-}
-
 // FindRollbackStage finds the rollback stage in stage list.
 func (d *Deployment) FindRollbackStage() (*PipelineStage, bool) {
 	for i := len(d.Stages) - 1; i >= 0; i-- {