diff --git a/apis/v1beta1/types.go b/apis/v1beta1/types.go
index 01c8a37b8f..142e4f0bbd 100644
--- a/apis/v1beta1/types.go
+++ b/apis/v1beta1/types.go
@@ -205,6 +205,8 @@ type VirtualMachineCloneSpec struct {
 	HardwareVersion string `json:"hardwareVersion,omitempty"`
 	// DataDisks are additional disks to add to the VM that are not part of the VM's OVA template.
 	// +optional
+	// +listType=map
+	// +listMapKey=name
 	DataDisks []VSphereDisk `json:"dataDisks,omitempty"`
 }
 
@@ -213,7 +215,6 @@ type VSphereDisk struct {
 	// Name is used to identify the disk definition. If Name is not specified, the disk will still be created.
 	// The Name should be unique so that it can be used to clearly identify purpose of the disk, but is not
 	// required to be unique.
-	// +optional
 	Name string `json:"name,omitempty"`
 	// SizeGiB is the size of the disk in GiB.
 	// +kubebuilder:validation:Required