diff --git a/modules/compute/security-groups/main.tf b/modules/compute/security-groups/main.tf
index 189a435..be6bc55 100644
--- a/modules/compute/security-groups/main.tf
+++ b/modules/compute/security-groups/main.tf
@@ -3,10 +3,7 @@ resource "aws_security_group" "sg" {
   name        = var.security-groups[count.index].name
   description = var.security-groups[count.index].description
   vpc_id      = var.vpc-id
-  tags = merge(
-    var.tags,
-    {Name = var.security-groups[count.index].name}
-  )
+  tags =  { Name = var.security-groups[count.index].name }
 }
 
 // see https://www.terraform.io/docs/configuration/functions/flatten.html
diff --git a/modules/compute/security_group/main.tf b/modules/compute/security_group/main.tf
index 136c277..590eb9b 100644
--- a/modules/compute/security_group/main.tf
+++ b/modules/compute/security_group/main.tf
@@ -1,4 +1,11 @@
-data aws_default_tags this {}
+data "aws_default_tags" "this" {
+  lifecycle {
+    postcondition {
+      condition     = length(self.tags) >= 1
+      error_message = "Validation failed: Provider default_tags not set."
+    }
+  }
+}
 
 resource "aws_security_group" "sg" {
   name        = var.name