tofu setup

.tofu/platforms/gke/workload/main.tf

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+# =============================================================================
+# GCP Workload Cluster
+# =============================================================================
+# A lean GKE cluster for running application workloads. No managed data
+# services — those live on the platform cluster. ArgoCD (on the platform
+# cluster) deploys apps to this cluster via the app-of-apps pattern.
+#
+# Platform components deployed by deploy-workload.sh:
+#   nginx-ingress, cert-manager, external-dns, external-secrets, alloy
+#
+# Usage:
+#   tofu init && tofu plan && tofu apply
+#   ./sync-tofu-outputs.sh --env gcp-workload
+#   ./deploy-workload.sh --env gcp-workload
+# =============================================================================
+
+variable "prefix" {
+  description = "Prefix for resource names (e.g., devhub-workload)"
+  type        = string
+  default     = "devhub-workload"
+}
+
+variable "node_machine_type" {
+  description = "GKE node machine type"
+  type        = string
+  default     = "e2-standard-2"
+}
+
+variable "node_count" {
+  description = "Number of nodes per zone"
+  type        = number
+  default     = 1
+}
+
+variable "kubernetes_version" {
+  description = "GKE Kubernetes version (null = STABLE release channel)"
+  type        = string
+  default     = null
+}
+
+variable "deletion_protection" {
+  description = "Prevent cluster deletion"
+  type        = bool
+  default     = false
+}
+
+variable "labels" {
+  description = "Labels applied to all resources"
+  type        = map(string)
+  default = {
+    environment = "workload"
+    managed-by  = "tofu"
+  }
+}
+
+# ─── Required APIs ────────────────────────────────────────────────────
+
+resource "google_project_service" "compute" {
+  project            = var.project_id
+  service            = "compute.googleapis.com"
+  disable_on_destroy = false
+}
+
+resource "google_project_service" "container" {
+  project            = var.project_id
+  service            = "container.googleapis.com"
+  disable_on_destroy = false
+}
+
+resource "google_project_service" "iam" {
+  project            = var.project_id
+  service            = "iam.googleapis.com"
+  disable_on_destroy = false
+}
+
+resource "google_project_service" "dns" {
+  project            = var.project_id
+  service            = "dns.googleapis.com"
+  disable_on_destroy = false
+}
+
+# ─── Networking ───────────────────────────────────────────────────────
+
+resource "google_compute_network" "main" {
+  project                 = var.project_id
+  name                    = "${var.prefix}-vpc"
+  auto_create_subnetworks = false
+
+  depends_on = [google_project_service.compute]
+}
+
+resource "google_compute_subnetwork" "main" {
+  project       = var.project_id
+  name          = "${var.prefix}-subnet"
+  ip_cidr_range = "10.110.0.0/22"
+  region        = var.region
+  network       = google_compute_network.main.id
+
+  secondary_ip_range {
+    range_name    = "pods"
+    ip_cidr_range = "10.210.0.0/14"
+  }
+
+  secondary_ip_range {
+    range_name    = "services"
+    ip_cidr_range = "10.214.0.0/20"
+  }
+}
+
+# ─── GKE Cluster ──────────────────────────────────────────────────────
+
+resource "google_container_cluster" "main" {
+  project  = var.project_id
+  name     = "${var.prefix}-gke"
+  location = var.region
+
+  network    = google_compute_network.main.id
+  subnetwork = google_compute_subnetwork.main.id
+
+  ip_allocation_policy {
+    cluster_secondary_range_name  = "pods"
+    services_secondary_range_name = "services"
+  }
+
+  workload_identity_config {
+    workload_pool = "${var.project_id}.svc.id.goog"
+  }
+
+  remove_default_node_pool = true
+  initial_node_count       = 1
+
+  deletion_protection = var.deletion_protection
+
+  dynamic "release_channel" {
+    for_each = var.kubernetes_version == null ? [1] : []
+    content {
+      channel = "STABLE"
+    }
+  }
+
+  resource_labels = var.labels
+
+  depends_on = [google_project_service.container]
+}
+
+resource "google_container_node_pool" "main" {
+  project    = var.project_id
+  name       = "${var.prefix}-nodes"
+  location   = var.region
+  cluster    = google_container_cluster.main.name
+  node_count = var.node_count
+
+  node_config {
+    machine_type = var.node_machine_type
+
+    workload_metadata_config {
+      mode = "GKE_METADATA"
+    }
+
+    oauth_scopes = [
+      "https://www.googleapis.com/auth/cloud-platform",
+    ]
+
+    labels = merge(var.labels, { role = "worker" })
+  }
+
+  management {
+    auto_repair  = true
+    auto_upgrade = true
+  }
+}
+
+# ─── External-DNS Workload Identity ──────────────────────────────────
+# Allows external-dns to manage Cloud DNS records for app ingresses.
+
+resource "google_service_account" "external_dns" {
+  project      = var.project_id
+  account_id   = "${var.prefix}-external-dns"
+  display_name = "External-DNS Service Account (Workload Identity)"
+
+  depends_on = [google_project_service.iam]
+}
+
+resource "google_project_iam_member" "external_dns_dns_admin" {
+  project = var.project_id
+  role    = "roles/dns.admin"
+  member  = "serviceAccount:${google_service_account.external_dns.email}"
+}
+
+resource "google_service_account_iam_member" "external_dns_workload_identity" {
+  service_account_id = google_service_account.external_dns.name
+  role               = "roles/iam.workloadIdentityUser"
+  member             = "serviceAccount:${var.project_id}.svc.id.goog[external-dns/external-dns]"
+}