diff --git a/Makefile b/Makefile
index 8d0d811..c199d45 100644
--- a/Makefile
+++ b/Makefile
@@ -31,10 +31,7 @@ $(GENERATED): $(CRD_TYPE_SOURCE)
 	bash -x ./hack/update-codegen.sh
 
 $(GENERATED_CRD): go.mod $(GENERATED)
-	go run sigs.k8s.io/controller-tools/cmd/controller-gen@v0.14.0 crd:crdVersions=v1 paths=./apis/... output:crd:dir=.
-	# workaround to add validation to array items. Not supported by controller-gen
-	# ref: https://github.com/kubernetes-sigs/controller-tools/issues/342
-	go run hack/crd/add_hosts_validation.go $(GENERATED_CRD)
+	go run sigs.k8s.io/controller-tools/cmd/controller-gen@master crd:crdVersions=v1 paths=./apis/... output:crd:dir=.
 
 build.local: $(LOCAL_BINARIES) $(GENERATED_CRD)
 build.linux: $(LINUX_BINARIES) $(GENERATED_CRD)
diff --git a/apis/zalando.org/v1/types.go b/apis/zalando.org/v1/types.go
index d20021a..beb2c86 100644
--- a/apis/zalando.org/v1/types.go
+++ b/apis/zalando.org/v1/types.go
@@ -43,6 +43,8 @@ type RouteGroupList struct {
 type RouteGroupSpec struct {
 	// List of hostnames for the RouteGroup
 	// +kubebuilder:validation:MinItems=1
+	// +kubebuilder:validation:items:MaxLength=255
+	// +kubebuilder:validation:items:Pattern="^[a-z0-9]([-a-z0-9]*[a-z0-9])?([.][a-z0-9]([-a-z0-9]*[a-z0-9])?)*$"
 	// +listType=set
 	Hosts []string `json:"hosts,omitempty"`
 	// List of backends that can be referenced in the routes
@@ -180,6 +182,8 @@ type RouteGroupTLSSpec struct {
 	// The values in this list must match the host name(s) used for
 	// the RouteGroup in order to terminate TLS for the host(s).
 	// +kubebuilder:validation:MinItems=1
+	// +kubebuilder:validation:items:MaxLength=255
+	// +kubebuilder:validation:items:Pattern="^[a-z0-9]([-a-z0-9]*[a-z0-9])?([.][a-z0-9]([-a-z0-9]*[a-z0-9])?)*$"
 	// +listType=set
 	Hosts []string `json:"hosts"`
 
diff --git a/hack/crd/add_hosts_validation.go b/hack/crd/add_hosts_validation.go
deleted file mode 100644
index c9aedb5..0000000
--- a/hack/crd/add_hosts_validation.go
+++ /dev/null
@@ -1,93 +0,0 @@
-// This program adds host validation to CRD yaml.
-//
-// # Why
-//
-// controller-gen does not support validating internal list items on list types,
-// see https://github.com/kubernetes-sigs/controller-tools/issues/342
-package main
-
-import (
-	"log"
-	"os"
-
-	"sigs.k8s.io/yaml"
-)
-
-const (
-	hostPattern   = `^[a-z0-9]([-a-z0-9]*[a-z0-9])?([.][a-z0-9]([-a-z0-9]*[a-z0-9])?)*$`
-	hostMaxLength = 255 // https://datatracker.ietf.org/doc/html/rfc1035#section-2.3.4
-)
-
-func must(err error) {
-	if err != nil {
-		log.Fatal(err)
-	}
-}
-
-func mustGet(v []byte, err error) []byte {
-	must(err)
-	return v
-}
-
-type setter struct {
-	o interface{}
-}
-
-func (s *setter) field(name string) *setter {
-	return &setter{s.o.(map[string]interface{})[name]}
-}
-
-func (s *setter) item(i int) *setter {
-	return &setter{s.o.([]interface{})[i]}
-}
-
-func (s *setter) setField(name string, value interface{}) *setter {
-	s.o.(map[string]interface{})[name] = value
-	return s
-}
-
-func main() {
-	if len(os.Args) != 2 {
-		log.Fatalf("CRD filename required")
-	}
-	crdFilename := os.Args[1]
-
-	yamlBytes := mustGet(os.ReadFile(crdFilename))
-
-	o := make(map[string]interface{})
-	must(yaml.Unmarshal(yamlBytes, &o))
-
-	s := &setter{o}
-
-	s.field("spec").
-		field("versions").
-		item(0).
-		field("schema").
-		field("openAPIV3Schema").
-		field("properties").
-		field("spec").
-		field("properties").
-		field("hosts").
-		field("items").
-		setField("pattern", hostPattern).
-		setField("maxLength", hostMaxLength)
-
-	s.field("spec").
-		field("versions").
-		item(0).
-		field("schema").
-		field("openAPIV3Schema").
-		field("properties").
-		field("spec").
-		field("properties").
-		field("tls").
-		field("items").
-		field("properties").
-		field("hosts").
-		field("items").
-		setField("pattern", hostPattern).
-		setField("maxLength", hostMaxLength)
-
-	outYaml := mustGet(yaml.Marshal(o))
-	must(os.WriteFile(crdFilename, outYaml, 0664))
-}
diff --git a/zalando.org_routegroups.yaml b/zalando.org_routegroups.yaml
index d0e0d4c..cb76943 100644
--- a/zalando.org_routegroups.yaml
+++ b/zalando.org_routegroups.yaml
@@ -1,8 +1,9 @@
+---
 apiVersion: apiextensions.k8s.io/v1
 kind: CustomResourceDefinition
 metadata:
   annotations:
-    controller-gen.kubebuilder.io/version: v0.14.0
+    controller-gen.kubebuilder.io/version: v0.14.1-0.20240403150007-6bbabbc0dad8
   name: routegroups.zalando.org
 spec:
   group: zalando.org