Add support for scale_down_mode (#285)

* add support for `scale_down_mode`

Co-authored-by: zjhe <hezijie@microsoft.com>

Author: lonegunmanb

README.md

@@ -351,6 +351,7 @@ No modules.
 | <a name="input_rbac_aad_tenant_id"></a> [rbac\_aad\_tenant\_id](#input\_rbac\_aad\_tenant\_id)                                                                                                    | (Optional) The Tenant ID used for Azure Active Directory Application. If this isn't specified the Tenant ID of the current Subscription is used.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | `string`                                                                                                                                                                                                                   | `null`                      |    no    |
 | <a name="input_resource_group_name"></a> [resource\_group\_name](#input\_resource\_group\_name)                                                                                                   | The resource group name to be imported                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | `string`                                                                                                                                                                                                                   | n/a                         |   yes    |
 | <a name="input_role_based_access_control_enabled"></a> [role\_based\_access\_control\_enabled](#input\_role\_based\_access\_control\_enabled)                                                     | Enable Role Based Access Control.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | `bool`                                                                                                                                                                                                                     | `false`                     |    no    |
+| <a name="input_scale_down_mode"></a> [scale\_down\_mode](#input\_scale\_down\_mode)                                                                                                               | (Optional) Specifies the autoscaling behaviour of the Kubernetes Cluster. If not specified, it defaults to `Delete`. Possible values include `Delete` and `Deallocate`. Changing this forces a new resource to be created.                                                                                                                                                                                                                                                                                                                                                                                                                                             | `string`                                                                                                                                                                                                                   | `"Delete"`                  |    no    |
 | <a name="input_secret_rotation_enabled"></a> [secret\_rotation\_enabled](#input\_secret\_rotation\_enabled)                                                                                       | Is secret rotation enabled? This variable is only used when `key_vault_secrets_provider_enabled` is `true` and defaults to `false`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | `bool`                                                                                                                                                                                                                     | `false`                     |    no    |
 | <a name="input_secret_rotation_interval"></a> [secret\_rotation\_interval](#input\_secret\_rotation\_interval)                                                                                    | The interval to poll for secret rotation. This attribute is only set when `secret_rotation` is `true` and defaults to `2m`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | `string`                                                                                                                                                                                                                   | `"2m"`                      |    no    |
 | <a name="input_sku_tier"></a> [sku\_tier](#input\_sku\_tier)                                                                                                                                      | The SKU Tier that should be used for this Kubernetes Cluster. Possible values are `Free` and `Paid`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | `string`                                                                                                                                                                                                                   | `"Free"`                    |    no    |

main.tf

@@ -56,6 +56,7 @@ resource "azurerm_kubernetes_cluster" "main" {
       os_disk_size_gb              = var.os_disk_size_gb
       os_disk_type                 = var.os_disk_type
       pod_subnet_id                = var.pod_subnet_id
+      scale_down_mode              = var.scale_down_mode
       tags                         = merge(var.tags, var.agents_tags)
       type                         = var.agents_type
       ultra_ssd_enabled            = var.ultra_ssd_enabled
@@ -81,6 +82,7 @@ resource "azurerm_kubernetes_cluster" "main" {
       os_disk_size_gb              = var.os_disk_size_gb
       os_disk_type                 = var.os_disk_type
       pod_subnet_id                = var.pod_subnet_id
+      scale_down_mode              = var.scale_down_mode
       tags                         = merge(var.tags, var.agents_tags)
       type                         = var.agents_type
       ultra_ssd_enabled            = var.ultra_ssd_enabled

variables.tf

@@ -98,7 +98,9 @@ variable "automatic_channel_upgrade" {
   default     = null
   description = "(Optional) The upgrade channel for this Kubernetes Cluster. Possible values are `patch`, `rapid`, `node-image` and `stable`. By default automatic-upgrades are turned off. Note that you cannot use the `patch` upgrade channel and still specify the patch version using `kubernetes_version`. See [the documentation](https://learn.microsoft.com/en-us/azure/aks/auto-upgrade-cluster) for more information"
   validation {
-    condition     = var.automatic_channel_upgrade == null ? true : contains(["patch", "stable", "rapid", "node-image"], var.automatic_channel_upgrade)
+    condition = var.automatic_channel_upgrade == null ? true : contains([
+      "patch", "stable", "rapid", "node-image"
+    ], var.automatic_channel_upgrade)
     error_message = "`automatic_channel_upgrade`'s possible values are `patch`, `stable`, `rapid` or `node-image`."
   }
 }
@@ -520,6 +522,12 @@ variable "role_based_access_control_enabled" {
   nullable    = false
 }
 
+variable "scale_down_mode" {
+  type        = string
+  description = "(Optional) Specifies the autoscaling behaviour of the Kubernetes Cluster. If not specified, it defaults to `Delete`. Possible values include `Delete` and `Deallocate`. Changing this forces a new resource to be created."
+  default     = "Delete"
+}
+
 variable "secret_rotation_enabled" {
   type        = bool
   description = "Is secret rotation enabled? This variable is only used when `key_vault_secrets_provider_enabled` is `true` and defaults to `false`"