kubernetes-sigs · VijetaPriya47 · Jan 19, 2026 · Jan 19, 2026
diff --git a/Makefile b/Makefile
@@ -128,6 +128,16 @@ CONVERSION_GEN_BIN := conversion-gen
 CONVERSION_GEN := $(abspath $(TOOLS_BIN_DIR)/$(CONVERSION_GEN_BIN))
 CONVERSION_GEN_PKG := k8s.io/code-generator/cmd/conversion-gen
 
+CLIENT_GEN_VER := v0.35.0
+CLIENT_GEN_BIN := client-gen
+CLIENT_GEN := $(abspath $(TOOLS_BIN_DIR)/$(CLIENT_GEN_BIN))
+CLIENT_GEN_PKG := k8s.io/code-generator/cmd/client-gen
+
+APPLYCONFIGURATION_GEN_VER := v0.35.0
+APPLYCONFIGURATION_GEN_BIN := applyconfiguration-gen
+APPLYCONFIGURATION_GEN := $(abspath $(TOOLS_BIN_DIR)/$(APPLYCONFIGURATION_GEN_BIN))
+APPLYCONFIGURATION_GEN_PKG := k8s.io/code-generator/cmd/applyconfiguration-gen
+
 GO_APIDIFF_VER := v0.8.3
 GO_APIDIFF_BIN := go-apidiff
 GO_APIDIFF := $(abspath $(TOOLS_BIN_DIR)/$(GO_APIDIFF_BIN)-$(GO_APIDIFF_VER))
@@ -276,7 +286,7 @@ ALL_GENERATE_MODULES = core kubeadm-bootstrap kubeadm-control-plane docker-infra
 
 .PHONY: generate
 generate: ## Run all generate-manifests-*, generate-go-deepcopy-*, generate-go-conversions-* and generate-go-openapi targets
-	$(MAKE) generate-modules generate-manifests generate-go-deepcopy generate-go-conversions generate-go-openapi
+	$(MAKE) generate-modules generate-manifests generate-go-deepcopy generate-go-conversions generate-go-openapi generate-go-applyconfigurations generate-go-client
 
 .PHONY: generate-manifests
 generate-manifests: $(addprefix generate-manifests-,$(ALL_GENERATE_MODULES)) ## Run all generate-manifests-* targets
@@ -538,6 +548,30 @@ generate-go-openapi: $(OPENAPI_GEN) ## Generate openapi go code for runtime SDK
 	done; \
 	rm sigs.k8s.io/cluster-api
 
+.PHONY: generate-go-applyconfigurations
+generate-go-applyconfigurations: $(APPLYCONFIGURATION_GEN) ## Generate apply configurations for Cluster API types
+	@echo "** Generating apply configurations **"
+	$(APPLYCONFIGURATION_GEN) \
+		--go-header-file=./hack/boilerplate/boilerplate.generatego.txt \
+		--output-pkg=sigs.k8s.io/cluster-api/pkg/generated/applyconfiguration \
+		--output-dir=./pkg/generated/applyconfiguration \
+		sigs.k8s.io/cluster-api/api/core/v1beta2 \
+		sigs.k8s.io/cluster-api/api/addons/v1beta2 \
+		sigs.k8s.io/cluster-api/api/bootstrap/kubeadm/v1beta2 \
+		sigs.k8s.io/cluster-api/api/controlplane/kubeadm/v1beta2
+
+.PHONY: generate-go-client
+generate-go-client: generate-go-applyconfigurations $(CLIENT_GEN) ## Generate typed client for Cluster API types
+	@echo "** Generating typed client **"
+	$(CLIENT_GEN) \
+		--go-header-file=./hack/boilerplate/boilerplate.generatego.txt \
+		--input=core/v1beta2,addons/v1beta2,bootstrap/kubeadm/v1beta2,controlplane/kubeadm/v1beta2 \
+		--input-base=sigs.k8s.io/cluster-api/api \
+		--apply-configuration-package=sigs.k8s.io/cluster-api/pkg/generated/applyconfiguration \
+		--clientset-name=clientset \
+		--output-pkg=sigs.k8s.io/cluster-api/pkg/generated/client \
+		--output-dir=./pkg/generated/client
+
 .PHONY: generate-modules
 generate-modules: ## Run go mod tidy to ensure modules are up to date
 	go mod tidy
@@ -1355,6 +1389,14 @@ clean-generated-conversions: ## Remove files generated by conversion-gen from th
 clean-generated-openapi-definitions: ## Remove files generated by openapi-gen from the mentioned dirs. Example SRC_DIRS="./api/v1alpha4"
 	(IFS=','; for i in $(SRC_DIRS); do find $$i -type f -name 'zz_generated.openapi*' -exec rm -f {} \;; done)
 
+.PHONY: clean-generated-applyconfigurations
+clean-generated-applyconfigurations: ## Remove generated applyconfiguration files
+	rm -rf ./pkg/generated/applyconfiguration
+
+.PHONY: clean-generated-client
+clean-generated-client: ## Remove generated client files
+	rm -rf ./pkg/generated/client
+
 ## --------------------------------------
 ## Hack / Tools
 ## --------------------------------------
@@ -1424,6 +1466,14 @@ $(CONTROLLER_GEN): # Build controller-gen from tools folder.
 $(CONVERSION_GEN): # Build conversion-gen from tools folder.
 	GOBIN=$(TOOLS_BIN_DIR) $(GO_INSTALL) $(CONVERSION_GEN_PKG) $(CONVERSION_GEN_BIN) $(CONVERSION_GEN_VER)
 
+.PHONY: $(CLIENT_GEN)
+$(CLIENT_GEN): # Build client-gen from tools folder.
+	GOBIN=$(TOOLS_BIN_DIR) $(GO_INSTALL) $(CLIENT_GEN_PKG) $(CLIENT_GEN_BIN) $(CLIENT_GEN_VER)
+
+.PHONY: $(APPLYCONFIGURATION_GEN)
+$(APPLYCONFIGURATION_GEN): # Build applyconfiguration-gen from tools folder.
+	GOBIN=$(TOOLS_BIN_DIR) $(GO_INSTALL) $(APPLYCONFIGURATION_GEN_PKG) $(APPLYCONFIGURATION_GEN_BIN) $(APPLYCONFIGURATION_GEN_VER)
+
 $(CONVERSION_VERIFIER): $(TOOLS_DIR)/go.mod # Build conversion-verifier from tools folder.
 	cd $(TOOLS_DIR); go build -tags=tools -o $(BIN_DIR)/$(CONVERSION_VERIFIER_BIN) sigs.k8s.io/cluster-api/hack/tools/conversion-verifier
 

diff --git a/api/addons/v1beta2/clusterresourceset_types.go b/api/addons/v1beta2/clusterresourceset_types.go
@@ -189,6 +189,8 @@ func (m *ClusterResourceSet) SetConditions(conditions []metav1.Condition) {
 // +kubebuilder:printcolumn:name="Applied",type="string",JSONPath=`.status.conditions[?(@.type=="ResourcesApplied")].status`,description="Resource applied"
 // +kubebuilder:printcolumn:name="Paused",type="string",JSONPath=`.status.conditions[?(@.type=="Paused")].status`,description="Reconciliation paused",priority=10
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of ClusterResourceSet"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // ClusterResourceSet is the Schema for the clusterresourcesets API.
 // For advanced use cases an add-on provider should be used instead.

diff --git a/api/addons/v1beta2/clusterresourcesetbinding_types.go b/api/addons/v1beta2/clusterresourcesetbinding_types.go
@@ -116,6 +116,8 @@ func (c *ClusterResourceSetBinding) RemoveBinding(clusterResourceSet *ClusterRes
 // +kubebuilder:storageversion
 // +kubebuilder:printcolumn:name="Cluster",type="string",JSONPath=".spec.clusterName",description="Cluster"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of ClusterResourceSetBinding"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // ClusterResourceSetBinding lists all matching ClusterResourceSets with the cluster it belongs to.
 type ClusterResourceSetBinding struct {

diff --git a/api/bootstrap/kubeadm/v1beta2/kubeadmconfig_types.go b/api/bootstrap/kubeadm/v1beta2/kubeadmconfig_types.go
@@ -530,6 +530,8 @@ type KubeadmConfigV1Beta1DeprecatedStatus struct {
 // +kubebuilder:printcolumn:name="Paused",type="string",JSONPath=`.status.conditions[?(@.type=="Paused")].status`,description="Reconciliation paused",priority=10
 // +kubebuilder:printcolumn:name="Data secret created",type="string",JSONPath=`.status.initialization.dataSecretCreated`,description="Boostrap secret is created"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of KubeadmConfig"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // KubeadmConfig is the Schema for the kubeadmconfigs API.
 type KubeadmConfig struct {

diff --git a/api/controlplane/kubeadm/v1beta2/kubeadm_control_plane_types.go b/api/controlplane/kubeadm/v1beta2/kubeadm_control_plane_types.go
@@ -829,6 +829,8 @@ type LastRemediationStatus struct {
 // +kubebuilder:printcolumn:name="Initialized",type=boolean,JSONPath=".status.initialization.controlPlaneInitialized",description="This denotes whether or not the control plane can accept requests"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of KubeadmControlPlane"
 // +kubebuilder:printcolumn:name="Version",type=string,JSONPath=".spec.version",description="Kubernetes version associated with this control plane"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // KubeadmControlPlane is the Schema for the KubeadmControlPlane API.
 type KubeadmControlPlane struct {

diff --git a/api/core/v1beta2/cluster_types.go b/api/core/v1beta2/cluster_types.go
@@ -1575,6 +1575,8 @@ func (v APIEndpoint) String() string {
 // +kubebuilder:printcolumn:name="Phase",type="string",JSONPath=".status.phase",description="Cluster status such as Pending/Provisioning/Provisioned/Deleting/Failed"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of Cluster"
 // +kubebuilder:printcolumn:name="Version",type="string",JSONPath=".spec.topology.version",description="Kubernetes version associated with this Cluster"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // Cluster is the Schema for the clusters API.
 type Cluster struct {

diff --git a/api/core/v1beta2/clusterclass_types.go b/api/core/v1beta2/clusterclass_types.go
@@ -72,6 +72,8 @@ const (
 // +kubebuilder:printcolumn:name="Paused",type="string",JSONPath=`.status.conditions[?(@.type=="Paused")].status`,description="Reconciliation paused",priority=10
 // +kubebuilder:printcolumn:name="Variables Ready",type="string",JSONPath=`.status.conditions[?(@.type=="VariablesReady")].status`,description="Variables ready"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of ClusterClass"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // ClusterClass is a template which can be used to create managed topologies.
 // NOTE: This CRD can only be used if the ClusterTopology feature gate is enabled.

diff --git a/api/core/v1beta2/machine_types.go b/api/core/v1beta2/machine_types.go
@@ -793,6 +793,8 @@ type Bootstrap struct {
 // +kubebuilder:printcolumn:name="Phase",type="string",JSONPath=".status.phase",description="Machine status such as Terminating/Pending/Running/Failed etc"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of Machine"
 // +kubebuilder:printcolumn:name="Version",type="string",JSONPath=".spec.version",description="Kubernetes version associated with this Machine"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // Machine is the Schema for the machines API.
 type Machine struct {

diff --git a/api/core/v1beta2/machinedeployment_types.go b/api/core/v1beta2/machinedeployment_types.go
@@ -584,6 +584,8 @@ func (md *MachineDeploymentStatus) GetTypedPhase() MachineDeploymentPhase {
 // +kubebuilder:printcolumn:name="Phase",type="string",JSONPath=".status.phase",description="MachineDeployment status such as ScalingUp/ScalingDown/Running/Failed/Unknown"
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of MachineDeployment"
 // +kubebuilder:printcolumn:name="Version",type="string",JSONPath=".spec.template.spec.version",description="Kubernetes version associated with this MachineDeployment"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // MachineDeployment is the Schema for the machinedeployments API.
 type MachineDeployment struct {

diff --git a/api/core/v1beta2/machinehealthcheck_types.go b/api/core/v1beta2/machinehealthcheck_types.go
@@ -343,6 +343,8 @@ type MachineHealthCheckV1Beta1DeprecatedStatus struct {
 // +kubebuilder:printcolumn:name="Healthy",type="integer",JSONPath=".status.currentHealthy",description="Current observed healthy machines"
 // +kubebuilder:printcolumn:name="Paused",type="string",JSONPath=`.status.conditions[?(@.type=="Paused")].status`,description="Reconciliation paused",priority=10
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of MachineHealthCheck"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // MachineHealthCheck is the Schema for the machinehealthchecks API.
 type MachineHealthCheck struct {

diff --git a/api/core/v1beta2/machinepool_types.go b/api/core/v1beta2/machinepool_types.go
@@ -333,6 +333,8 @@ func (m *MachinePoolStatus) GetTypedPhase() MachinePoolPhase {
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of MachinePool"
 // +kubebuilder:printcolumn:name="Version",type="string",JSONPath=".spec.template.spec.version",description="Kubernetes version associated with this MachinePool"
 // +k8s:conversion-gen=false
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // MachinePool is the Schema for the machinepools API.
 // NOTE: This CRD can only be used if the MachinePool feature gate is enabled.

diff --git a/api/core/v1beta2/machineset_types.go b/api/core/v1beta2/machineset_types.go
@@ -458,6 +458,8 @@ func (m *MachineSet) Validate() field.ErrorList {
 // +kubebuilder:printcolumn:name="Paused",type="string",JSONPath=`.status.conditions[?(@.type=="Paused")].status`,description="Reconciliation paused",priority=10
 // +kubebuilder:printcolumn:name="Age",type="date",JSONPath=".metadata.creationTimestamp",description="Time duration since creation of MachineSet"
 // +kubebuilder:printcolumn:name="Version",type="string",JSONPath=".spec.template.spec.version",description="Kubernetes version associated with this MachineSet"
+// +genclient
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
 // MachineSet is the Schema for the machinesets API.
 type MachineSet struct {

diff --git a/docs/book/src/SUMMARY.md b/docs/book/src/SUMMARY.md
@@ -71,6 +71,7 @@
     - [Developing "core" Cluster API](developer/core/overview.md)
         - [Rapid iterative development with Tilt](developer/core/tilt.md)
         - [Repository Layout](developer/core/repository-layout.md)
+        - [Using ApplyConfigurations for Server-Side Apply](./developer/architecture/apply-configurations.md)
         - [Controllers](./developer/core/controllers/overview.md)
           - [Cluster](./developer/core/controllers/cluster.md)
           - [ClusterTopology](./developer/core/controllers/cluster-topology.md)