diff --git a/cloud/const.go b/cloud/const.go
index 278f7e217..b99f22565 100644
--- a/cloud/const.go
+++ b/cloud/const.go
@@ -24,5 +24,5 @@ const (
 	CustomDataHashAnnotation = "sigs.k8s.io/cluster-api-provider-gcp-mig-custom-data-hash"
 
 	// ClusterAPIImagePrefix is the prefix for the image name used by the Cluster API provider for GCP.
-	ClusterAPIImagePrefix = "capi-ubuntu-1804-k8s-"
+	ClusterAPIImagePrefix = "capi-ubuntu-2204-k8s-"
 )
diff --git a/exp/api/v1beta1/gcpmachinepool_types.go b/exp/api/v1beta1/gcpmachinepool_types.go
index 8c1b6b2f7..a5b1e0886 100644
--- a/exp/api/v1beta1/gcpmachinepool_types.go
+++ b/exp/api/v1beta1/gcpmachinepool_types.go
@@ -80,8 +80,10 @@ type ServiceAccount struct {
 // MetadataItem is a key/value pair to add to the instance's metadata.
 type MetadataItem struct {
 	// Key is the identifier for the metadata entry.
+	// +optional
 	Key string `json:"key"`
 	// Value is the value of the metadata entry.
+	// +optional
 	Value *string `json:"value,omitempty"`
 }