feat: Add the SPOT support for Managed Node Groups (terraform-aws-modules#1129)

BREAKING CHANGES: To add add SPOT support for MNG, the `instance_type` is now a list and renamed as `instance_types`. This will probably rebuild existing Managed Node Groups.

Author: jonathan-mothership

examples/managed_node_groups/main.tf

@@ -100,7 +100,8 @@ module "eks" {
       max_capacity     = 10
       min_capacity     = 1
 
-      instance_type = "m5.large"
+      instance_types = ["m5.large"]
+      capacity_type  = "SPOT"
       k8s_labels = {
         Environment = "test"
         GithubRepo  = "terraform-aws-eks"

modules/node_groups/README.md

@@ -20,10 +20,11 @@ The role ARN specified in `var.default_iam_role_arn` will be used by default. In
 | additional\_tags | Additional tags to apply to node group | map(string) | Only `var.tags` applied |
 | ami\_release\_version | AMI version of workers | string | Provider default behavior |
 | ami\_type | AMI Type. See Terraform or AWS docs | string | Provider default behavior |
+| capacity\_type | Type of instance capacity to provision. Options are `ON_DEMAND` and `SPOT` | string | Provider default behavior |
 | desired\_capacity | Desired number of workers | number | `var.workers_group_defaults[asg_desired_capacity]` |
 | disk\_size | Workers' disk size | number | Provider default behavior |
 | iam\_role\_arn | IAM role ARN for workers | string | `var.default_iam_role_arn` |
-| instance\_type | Workers' instance type | string | `var.workers_group_defaults[instance_type]` |
+| instance\_types | Node group's instance type(s). Multiple types can be specified when `capacity_type="SPOT"`. | list | `[var.workers_group_defaults[instance_type]]` |
 | k8s\_labels | Kubernetes labels | map(string) | No labels applied |
 | key\_name | Key name for workers. Set to empty string to disable remote access | string | `var.workers_group_defaults[key_name]` |
 | launch_template_id | The id of a aws_launch_template to use | string | No LT used |

modules/node_groups/locals.tf

@@ -4,7 +4,7 @@ locals {
     {
       desired_capacity        = var.workers_group_defaults["asg_desired_capacity"]
       iam_role_arn            = var.default_iam_role_arn
-      instance_type           = var.workers_group_defaults["instance_type"]
+      instance_types          = [var.workers_group_defaults["instance_type"]]
       key_name                = var.workers_group_defaults["key_name"]
       launch_template_id      = var.workers_group_defaults["launch_template_id"]
       launch_template_version = var.workers_group_defaults["launch_template_version"]

modules/node_groups/node_groups.tf

@@ -15,8 +15,9 @@ resource "aws_eks_node_group" "workers" {
 
   ami_type        = lookup(each.value, "ami_type", null)
   disk_size       = lookup(each.value, "disk_size", null)
-  instance_types  = each.value["launch_template_id"] != null ? [] : [each.value["instance_type"]]
+  instance_types  = lookup(each.value, "instance_types", null)
   release_version = lookup(each.value, "ami_release_version", null)
+  capacity_type   = lookup(each.value, "capacity_type", null)
 
   dynamic "remote_access" {
     for_each = each.value["key_name"] != "" ? [{

modules/node_groups/random.tf

@@ -7,8 +7,11 @@ resource "random_pet" "node_groups" {
   keepers = {
     ami_type      = lookup(each.value, "ami_type", null)
     disk_size     = lookup(each.value, "disk_size", null)
-    instance_type = each.value["instance_type"]
+    capacity_type = lookup(each.value, "capacity_type", null)
     iam_role_arn  = each.value["iam_role_arn"]
+    instance_types = join("|", compact(
+      lookup(each.value, "instance_types", [])
+    ))
 
     key_name = each.value["key_name"]