diff --git a/_sub/compute/eks-heptio/main.tf b/_sub/compute/eks-heptio/main.tf
index e800c0288..54b328be6 100644
--- a/_sub/compute/eks-heptio/main.tf
+++ b/_sub/compute/eks-heptio/main.tf
@@ -30,7 +30,7 @@ resource "local_file" "default-configmap" {
 }
 
 resource "null_resource" "enable-workers-default" {
-  count = var.blaster_configmap_apply ? 0 : 1
+  count = length(var.blaster_configmap_s3_bucket) > 0 ? 0 : 1
 
   provisioner "local-exec" {
     command = "kubectl --kubeconfig ${var.kubeconfig_path} apply -f ${local.path_default_configmap}"
@@ -43,7 +43,7 @@ resource "null_resource" "enable-workers-default" {
 }
 
 resource "null_resource" "enable-workers-from-s3" {
-  count = var.blaster_configmap_apply ? 1 : 0
+  count = length(var.blaster_configmap_s3_bucket) > 0 ? 1 : 0
 
   # Terraform does not seem to re-run script, unless a trigger is defined
   triggers = {
diff --git a/_sub/compute/eks-heptio/vars.tf b/_sub/compute/eks-heptio/vars.tf
index 068aed841..b487bbdc3 100644
--- a/_sub/compute/eks-heptio/vars.tf
+++ b/_sub/compute/eks-heptio/vars.tf
@@ -18,13 +18,10 @@ variable "aws_assume_role_arn" {
   type = string
 }
 
-variable "blaster_configmap_apply" {
-  type    = bool
-  default = false
-}
 
 variable "blaster_configmap_s3_bucket" {
-  type = string
+  description = "The S3 bucket where the blaster configmap is stored. If empty default ConfigMap will be applied. If the bucket or object `var.blaster_configmap_key` specified does not exist, the default ConfigMap will also be used."
+  type        = string
 }
 
 variable "blaster_configmap_key" {
diff --git a/compute/eks-ec2/main.tf b/compute/eks-ec2/main.tf
index 053672b1a..3edc91540 100644
--- a/compute/eks-ec2/main.tf
+++ b/compute/eks-ec2/main.tf
@@ -282,7 +282,6 @@ module "eks_heptio" {
   eks_endpoint                = module.eks_cluster.eks_endpoint
   eks_certificate_authority   = module.eks_cluster.eks_certificate_authority
   eks_role_arn                = module.eks_workers.worker_role
-  blaster_configmap_apply     = length(var.blaster_configmap_bucket) >= 1 ? true : false
   blaster_configmap_s3_bucket = module.blaster_configmap_bucket.bucket_name
   blaster_configmap_key       = "configmap_${module.eks_heptio.cluster_name}_blaster.yml"
   aws_assume_role_arn         = var.aws_assume_role_arn