Introduce terraform vars 'disk_type' and 'disk_size_gb'

README.md

@@ -87,7 +87,7 @@ Have a look at the [variables.tf](./variables.tf) file how to further configure
 
 #### Magic Labels
 
-Each workflow job can select a different machine type than the configured default `machine_type`. This is done by the special label `@machine:c2d-standard-16`.
+Each workflow job can select a different machine type than the configured default `machine_type`. This is done by the special label `@machine:c2d-standard-16`. Make sure that the configured `disk_type` is supported by the machine.
 
 ```
 jobs:

compute.tf

@@ -26,8 +26,8 @@ resource "google_compute_instance_template" "runner_instance" {
     auto_delete  = true
     boot         = true
     source_image = var.machine_image
-    disk_type    = "pd-standard"
-    disk_size_gb = 40
+    disk_type    = var.disk_type
+    disk_size_gb = var.disk_size_gb
   }
 
   service_account {

variables.tf

@@ -4,6 +4,18 @@ variable "machine_type" {
   default     = "e2-micro"
 }
 
+variable "disk_type" {
+  type        = string
+  description = "The VM instance disk type"
+  default     = "pd-standard"
+}
+
+variable "disk_size_gb" {
+  type        = number
+  description = "The VM disk size"
+  default     = 40
+}
+
 variable "machine_image" {
   type        = string
   description = "The VM instance boot image (gcloud compute images list --filter ubuntu-os). Only Linux is supported!"