diff --git a/ecs-cluster/terraform.tf b/ecs-cluster/terraform.tf
index 446a5cd..6c15920 100644
--- a/ecs-cluster/terraform.tf
+++ b/ecs-cluster/terraform.tf
@@ -1,3 +1,10 @@
+# The Terraform state should be stored in S3, but you must configure the S3 bucket/prefix separately.
+# See example.s3.tfbackend
+terraform {
+  backend "s3" {
+  }
+}
+
 provider "aws" {
   region = var.region