diff --git a/azure/const.go b/azure/const.go
index 61eb35813b0..ff655a4c5d7 100644
--- a/azure/const.go
+++ b/azure/const.go
@@ -29,5 +29,9 @@ const (
 	// for annotation formatting rules.
 	RGTagsLastAppliedAnnotation = "sigs.k8s.io/cluster-api-provider-azure-last-applied-tags-rg"
 
-	CustomDataHash = "sigs.k8s.io/cluster-api-provider-azure-vmss-custom-data-hash"
+	// CustomDataHashAnnotation is the key for the machine object annotation
+	// which tracks the hash of the custom data.
+	// See https://kubernetes.io/docs/concepts/overview/working-with-objects/annotations/
+	// for annotation formatting rules.
+	CustomDataHashAnnotation = "sigs.k8s.io/cluster-api-provider-azure-vmss-custom-data-hash"
 )
diff --git a/azure/scope/machinepool.go b/azure/scope/machinepool.go
index a60b74c3b99..94910a17cfe 100644
--- a/azure/scope/machinepool.go
+++ b/azure/scope/machinepool.go
@@ -597,7 +597,7 @@ func (m *MachinePoolScope) HasBootstrapDataChanges(ctx context.Context) (bool, e
 	if err != nil {
 		return false, err
 	}
-	return m.AzureMachinePool.GetAnnotations()[azure.CustomDataHash] != newHash, nil
+	return m.AzureMachinePool.GetAnnotations()[azure.CustomDataHashAnnotation] != newHash, nil
 }
 
 // updateCustomDataHash calculates the sha256 hash of the bootstrap data and saves it in AzureMachinePool.Status.
@@ -606,7 +606,7 @@ func (m *MachinePoolScope) updateCustomDataHash(ctx context.Context) error {
 	if err != nil {
 		return err
 	}
-	m.SetAnnotation(azure.CustomDataHash, newHash)
+	m.SetAnnotation(azure.CustomDataHashAnnotation, newHash)
 	return nil
 }