diff --git a/testing/infra/terraform/modules/tags/vars.tf b/testing/infra/terraform/modules/tags/vars.tf
index 72bd8a5a15a..b4ca5f35985 100644
--- a/testing/infra/terraform/modules/tags/vars.tf
+++ b/testing/infra/terraform/modules/tags/vars.tf
@@ -1,3 +1,8 @@
 variable "project" {
   description = "The value to use for the project tag/label"
 }
+
+variable "build" {
+  description = "The value to use for the build tag/label"
+  default     = "unknown"
+}