feat(google_gke): expose node_pools_metadata for set-once node metadata

google_gke/README.md

@@ -414,6 +414,7 @@ module "gke" {
 | <a name="input_node_pools"></a> [node\_pools](#input\_node\_pools) | Map containing node pools, with each node pool's name (or name\_prefix if `use_name_prefix` is true) being the key and the values being that node pool's configurations. Configurable options per node pool include: `disk_size_gb` (string), `disk_type` (string), `machine_type` (string), `max_count` (number), `max_surge` (number), `max_unavailable` (number), `min_count` (number), `use_name_prefix` (bool). See locals.tf for defaults. | `list(map(string))` | <pre>[<br/>  {<br/>    "name": "tf-default-node-pool"<br/>  }<br/>]</pre> | no |
 | <a name="input_node_pools_guest_accelerator"></a> [node\_pools\_guest\_accelerator](#input\_node\_pools\_guest\_accelerator) | Map containing node pools guest accelerator. Each node pool's name is the key. See locals.tf for defaults. | `map(map(string))` | <pre>{<br/>  "tf-default-node-pool": {}<br/>}</pre> | no |
 | <a name="input_node_pools_labels"></a> [node\_pools\_labels](#input\_node\_pools\_labels) | Map containing node pools non-default labels (as a map of strings). Each key is used as node pool's name prefix. See locals.tf for defaults. | `map(map(string))` | <pre>{<br/>  "tf-default-node-pool": {}<br/>}</pre> | no |
+| <a name="input_node_pools_metadata"></a> [node\_pools\_metadata](#input\_node\_pools\_metadata) | Per-node-pool node metadata (key/value strings applied at pool creation, e.g. `serial-port-logging-enable: "false"`). Keyed by node pool name. NOTE: the module includes `node_config[0].metadata` in `lifecycle.ignore_changes`, so values here are applied ONLY at pool creation — drift / variable updates do not reconcile to existing pools. Use this for set-once hardening settings (rotate the pool to change them). | `map(map(string))` | `{}` | no |
 | <a name="input_node_pools_oauth_scopes"></a> [node\_pools\_oauth\_scopes](#input\_node\_pools\_oauth\_scopes) | Map containing node pools non-default OAuth scopes (as an list). Each node pool's name is the key. See locals.tf for defaults. | `map(list(string))` | <pre>{<br/>  "tf-default-node-pool": []<br/>}</pre> | no |
 | <a name="input_node_pools_shielded_instance_config"></a> [node\_pools\_shielded\_instance\_config](#input\_node\_pools\_shielded\_instance\_config) | Per-node-pool shielded instance config. Keyed by node pool name. Pools not present in this map fall back to GKE provider defaults (integrity monitoring on, secure boot off). Changing shielded\_instance\_config on an existing pool forces recreation, so opt in per pool. | <pre>map(object({<br/>    enable_secure_boot          = optional(bool, true)<br/>    enable_integrity_monitoring = optional(bool, true)<br/>  }))</pre> | `{}` | no |
 | <a name="input_node_pools_spot_enabled"></a> [node\_pools\_spot\_enabled](#input\_node\_pools\_spot\_enabled) | Map containing node pools spot enabled. Each node pool's name is the key. See locals.tf for defaults. | `map(bool)` | <pre>{<br/>  "tf-default-node-pool": false<br/>}</pre> | no |

google_gke/cluster.tf

@@ -290,6 +290,9 @@ resource "google_container_node_pool" "pools" {
     image_type      = "COS_CONTAINERD"
     labels          = local.node_pools_labels[each.key]
     logging_variant = var.enable_high_throughput_logging ? "MAX_THROUGHPUT" : "DEFAULT"
+    # Set-once metadata applied at pool creation. node_config[0].metadata is in
+    # ignore_changes below, so values here are not reconciled afterward.
+    metadata = length(local.node_pools_metadata[each.key]) > 0 ? local.node_pools_metadata[each.key] : null
 
     dynamic "guest_accelerator" {
       for_each = length(local.node_pools_guest_accelerator[each.key]) != 0 ? [1] : []

google_gke/locals.tf

@@ -57,6 +57,8 @@ locals {
 
   node_pools_shielded_instance_config = { for node_pool in var.node_pools : node_pool.name => lookup(var.node_pools_shielded_instance_config, node_pool.name, null) }
 
+  node_pools_metadata = { for node_pool in var.node_pools : node_pool.name => lookup(var.node_pools_metadata, node_pool.name, {}) }
+
   # Google Group for RBAC
   cluster_authenticator_security_group = var.google_group_name == null ? [] : [{
     security_group = var.google_group_name

google_gke/variables.tf

@@ -258,6 +258,12 @@ variable "node_pools_shielded_instance_config" {
   default = {}
 }
 
+variable "node_pools_metadata" {
+  description = "Per-node-pool node metadata (key/value strings applied at pool creation, e.g. `serial-port-logging-enable: \"false\"`). Keyed by node pool name. NOTE: the module includes `node_config[0].metadata` in `lifecycle.ignore_changes`, so values here are applied ONLY at pool creation — drift / variable updates do not reconcile to existing pools. Use this for set-once hardening settings (rotate the pool to change them)."
+  type        = map(map(string))
+  default     = {}
+}
+
 variable "node_pools_tags" {
   description = "Map containing node pools non-default tags (as an list). Each node pool's name is the key. See locals.tf for defaults."
   type        = map(list(string))