diff --git a/main.tf b/main.tf
index a3b2d1a828222f07ad9ba68bcc2d9597165e9667..6fe6395a59a369e5c6c731f21b93ab27e588496d 100644
--- a/main.tf
+++ b/main.tf
@@ -57,7 +57,7 @@ output "keypair_name" {
 data "openstack_networking_network_v2" "external_net" {name = var.external_network}
 data "openstack_blockstorage_volume_v2" "disk" {
   name = "var.data_volume"
-  metadata =  "id:volume_id"
+  metadata = { id = "volume_id" }
 }
 
 # runs the ohpc-instance module - creates ohpc instance using variables defined above