add option for fixed DNS server

files/cloud_init.cfg.tftpl

@@ -49,3 +49,9 @@ fs_setup:
 mounts:
 - ["data.1", "/mnt/data"]
 %{ endif }
+%{ if fixed_dns != "" }
+manage_resolv_conf: true
+resolv_conf:
+  nameservers:
+    - "${fixed_dns}"
+%{ endif }

main.tf

@@ -15,6 +15,7 @@ locals {
     host_cert             = trimspace(null_resource.cert.triggers["cert"]),
     private_key           = tls_private_key.debian.private_key_openssh,
     data_disk             = var.data_disk != null
+    fixed_dns             = var.fixed_dns
   })
   cloudinit_network_config = templatefile("${path.module}/files/network_config.cfg.tftpl", {
     fixed_address = var.fixed_address

variables.tf

@@ -74,3 +74,8 @@ variable "ansible_command" {
   type    = string
   default = "true"
 }
+
+variable "fixed_dns" {
+  type    = string
+  default = ""
+}