feat: enable L4 ILB subsetting support for safer clusters

Author: feliperfmarques

modules/safer-cluster-update-variant/README.md

@@ -221,6 +221,7 @@ For simplicity, we suggest using `roles/container.admin` and
 | enable\_cost\_allocation | Enables Cost Allocation Feature and the cluster name and namespace of your GKE workloads appear in the labels field of the billing export to BigQuery | `bool` | `false` | no |
 | enable\_gcfs | Enable image streaming on cluster level. | `bool` | `false` | no |
 | enable\_intranode\_visibility | Whether Intra-node visibility is enabled for this cluster. This makes same node pod to pod traffic visible for VPC network | `bool` | `false` | no |
+| enable\_l4\_ilb\_subsetting | Enable L4 ILB Subsetting on the cluster | `bool` | `false` | no |
 | enable\_mesh\_certificates | Controls the issuance of workload mTLS certificates. When enabled the GKE Workload Identity Certificates controller and node agent will be deployed in the cluster. Requires Workload Identity. | `bool` | `false` | no |
 | enable\_pod\_security\_policy | enabled - Enable the PodSecurityPolicy controller for this cluster. If enabled, pods must be valid under a PodSecurityPolicy to be created. | `bool` | `false` | no |
 | enable\_private\_endpoint | When true, the cluster's private endpoint is used as the cluster endpoint and access through the public endpoint is disabled. When false, either endpoint can be used. This field only applies to private clusters, when enable\_private\_nodes is true | `bool` | `true` | no |

modules/safer-cluster-update-variant/main.tf

@@ -165,6 +165,9 @@ module "gke" {
   // Enable cost allocation support
   enable_cost_allocation = var.enable_cost_allocation
 
+  // Enable L4 ILB subsetting on the cluster
+  enable_l4_ilb_subsetting = var.enable_l4_ilb_subsetting
+
   // Use of PodSecurityPolicy admission controller
   // https://cloud.google.com/kubernetes-engine/docs/how-to/pod-security-policies
   enable_pod_security_policy = var.enable_pod_security_policy

modules/safer-cluster-update-variant/variables.tf

@@ -379,6 +379,12 @@ variable "enable_cost_allocation" {
   default     = false
 }
 
+variable "enable_l4_ilb_subsetting" {
+  type        = bool
+  description = "Enable L4 ILB Subsetting on the cluster"
+  default     = false
+}
+
 variable "sandbox_enabled" {
   type        = bool
   description = "(Beta) Enable GKE Sandbox (Do not forget to set `image_type` = `COS_CONTAINERD` to use it)."