add option for fixed DNS

debian/main.tf

@@ -28,4 +28,5 @@ module "tf_debian_vm" {
   fixed_address         = var.fixed_address
   ansible_command       = var.ansible_command
   mac                   = var.mac
+  fixed_dns             = var.fixed_dns
 }

debian/variables.tf

@@ -76,3 +76,8 @@ variable "mac" {
   type    = string
   default = null
 }
+
+variable "fixed_dns" {
+  type = string
+  default = ""
+}