diff --git a/.modules/service/ecs.tf b/.modules/service/ecs.tf
index 696d508..c582599 100644
--- a/.modules/service/ecs.tf
+++ b/.modules/service/ecs.tf
@@ -20,8 +20,8 @@ resource "aws_ecs_task_definition" "task" {
   family                   = var.service_name
   cpu                      = var.ecs_cpu
   memory                   = var.ecs_memory
-  execution_role_arn       = var.ecs_execution_role_arn != "" ? var.ecs_execution_role_arn : aws_iam_role.ecs-execution.arn
-  task_role_arn            = var.ecs_task_execution_role_arn != "" ? var.ecs_task_execution_role_arn : aws_iam_role.task-execution.arn
+  execution_role_arn       = element(concat(aws_iam_role.ecs-execution.*.arn, list(var.ecs_execution_role_arn)), var.ecs_execution_role_arn == "" ? 0 : 1)
+  task_role_arn            = element(concat(aws_iam_role.task-execution.*.arn, list(var.ecs_task_execution_role_arn)), var.ecs_task_execution_role_arn == "" ? 0 : 1)
   network_mode             = "awsvpc"
   requires_compatibilities = [var.launch_type]
 
diff --git a/.modules/service/policy.tf b/.modules/service/policy.tf
index 6b4035d..e45d89d 100644
--- a/.modules/service/policy.tf
+++ b/.modules/service/policy.tf
@@ -19,7 +19,7 @@ resource "aws_iam_role" "ecs-execution" {
 resource "aws_iam_role_policy_attachment" "ecs-execution-managed" {
   count = var.ecs_execution_role_arn == "" ? 1 : 0
 
-  role       = var.ecs_execution_role_arn == "" ? aws_iam_role.ecs-execution.id : ""
+  role       = element(concat(aws_iam_role.ecs-execution.*.id, list("")), var.ecs_execution_role_arn == "" ? 0 : 1)
   policy_arn = "arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy"
 }
 
@@ -60,5 +60,5 @@ resource "aws_iam_role_policy" "task-role" {
   count = var.ecs_task_execution_role_arn == "" ? 1 : 0
 
   policy = data.aws_iam_policy_document.task-policy.json
-  role   = var.ecs_task_execution_role_arn == "" ? aws_iam_role.task-execution.id : ""
+  role   = element(concat(aws_iam_role.task-execution.*.id, list("")), var.ecs_task_execution_role_arn == "" ? 0 : 1)
 }