fix: Fixed launch template version infinite plan issue and improved rolling updates (#1447)

Author: jjhidalgar

modules/node_groups/README.md

@@ -48,6 +48,7 @@ The role ARN specified in `var.default_iam_role_arn` will be used by default. In
 | subnets | Subnets to contain workers | list(string) | `var.workers_group_defaults[subnets]` |
 | version | Kubernetes version | string | Provider default behavior |
 | taints | Kubernetes node taints | list(map) | empty |
+| update_default_version | Whether or not to set the new launch template version the Default | bool | `true` |
 
 <!-- BEGINNING OF PRE-COMMIT-TERRAFORM DOCS HOOK -->
 ## Requirements

modules/node_groups/launch_template.tf

@@ -27,7 +27,7 @@ resource "aws_launch_template" "workers" {
 
   name_prefix            = local.node_groups_names[each.key]
   description            = format("EKS Managed Node Group custom LT for %s", local.node_groups_names[each.key])
-  update_default_version = true
+  update_default_version = lookup(each.value, "update_default_version", true)
 
   block_device_mappings {
     device_name = "/dev/xvda"

modules/node_groups/locals.tf

@@ -24,6 +24,7 @@ locals {
       pre_userdata                  = var.workers_group_defaults["pre_userdata"]
       additional_security_group_ids = var.workers_group_defaults["additional_security_group_ids"]
       taints                        = []
+      update_default_version        = true
       ebs_optimized                 = null
     },
     var.node_groups_defaults,

modules/node_groups/node_groups.tf

@@ -47,8 +47,10 @@ resource "aws_eks_node_group" "workers" {
 
   dynamic "launch_template" {
     for_each = each.value["launch_template_id"] == null && each.value["create_launch_template"] ? [{
-      id      = aws_launch_template.workers[each.key].id
-      version = each.value["launch_template_version"]
+      id = aws_launch_template.workers[each.key].id
+      version = each.value["launch_template_version"] == "$Latest" ? aws_launch_template.workers[each.key].latest_version : (
+        each.value["launch_template_version"] == "$Default" ? aws_launch_template.workers[each.key].default_version : each.value["launch_template_version"]
+      )
     }] : []
 
     content {