feat: support setting instance_termination_action for Spot VMs (#346)

Co-authored-by: Awais Malik <[email protected]>

Author: tpdownes

modules/instance_template/README.md

@@ -47,6 +47,7 @@ See the [simple](../../examples/instance_template/simple) for a usage example.
 | source\_image\_family | Source image family. If neither source\_image nor source\_image\_family is specified, defaults to the latest public CentOS image. | `string` | `"centos-7"` | no |
 | source\_image\_project | Project where the source image comes from. The default project contains CentOS images. | `string` | `"centos-cloud"` | no |
 | spot | Provision a SPOT instance | `bool` | `false` | no |
+| spot\_instance\_termination\_action | Action to take when Compute Engine preempts a Spot VM. | `string` | `"STOP"` | no |
 | stack\_type | The stack type for this network interface to identify whether the IPv6 feature is enabled or not. Values are `IPV4_IPV6` or `IPV4_ONLY`. Default behavior is equivalent to IPV4\_ONLY. | `string` | `null` | no |
 | startup\_script | User startup script to run when instances spin up | `string` | `""` | no |
 | subnetwork | The name of the subnetwork to attach this interface to. The subnetwork must exist in the same region this instance will be created in. Either network or subnetwork must be provided. | `string` | `""` | no |

modules/instance_template/main.tf

@@ -177,7 +177,7 @@ resource "google_compute_instance_template" "tpl" {
     automatic_restart           = local.automatic_restart
     on_host_maintenance         = local.on_host_maintenance
     provisioning_model          = var.spot ? "SPOT" : null
-    instance_termination_action = var.spot ? "STOP" : null
+    instance_termination_action = var.spot ? var.spot_instance_termination_action : null
   }
 
   advanced_machine_features {

modules/instance_template/variables.tf

@@ -80,6 +80,17 @@ variable "on_host_maintenance" {
   default     = "MIGRATE"
 }
 
+variable "spot_instance_termination_action" {
+  description = "Action to take when Compute Engine preempts a Spot VM."
+  type        = string
+  default     = "STOP"
+
+  validation {
+    condition     = contains(["STOP", "DELETE"], var.spot_instance_termination_action)
+    error_message = "Allowed values for spot_instance_termination_action are: \"STOP\" or \"DELETE\"."
+  }
+}
+
 variable "region" {
   type        = string
   description = "Region where the instance template should be created."