Terraform GCP Skill

Production patterns for GCP infrastructure provisioning with Terraform.

Provider Setup

terraform {
  required_providers {
    google = {
      source  = "hashicorp/google"
      version = "~> 5.0"
    }
    google-beta = {
      source  = "hashicorp/google-beta"
      version = "~> 5.0"
    }
  }
}

provider "google" {
  project = var.project_id
  region  = var.region
}

VPC Network

resource "google_compute_network" "main" {
  name                    = "${var.project}-vpc"
  auto_create_subnetworks = false
  routing_mode            = "REGIONAL"
}

resource "google_compute_subnetwork" "private" {
  name          = "${var.project}-private"
  ip_cidr_range = "10.0.0.0/24"
  region        = var.region
  network       = google_compute_network.main.id

  private_ip_google_access = true

  secondary_ip_range {
    range_name    = "pods"
    ip_cidr_range = "10.1.0.0/16"
  }

  secondary_ip_range {
    range_name    = "services"
    ip_cidr_range = "10.2.0.0/16"
  }
}

resource "google_compute_router" "main" {
  name    = "${var.project}-router"
  region  = var.region
  network = google_compute_network.main.id
}

resource "google_compute_router_nat" "main" {
  name                               = "${var.project}-nat"
  router                             = google_compute_router.main.name
  region                             = var.region
  nat_ip_allocate_option             = "AUTO_ONLY"
  source_subnetwork_ip_ranges_to_nat = "ALL_SUBNETWORKS_ALL_IP_RANGES"
}

GKE Cluster

resource "google_container_cluster" "main" {
  provider = google-beta

  name     = "${var.project}-gke"
  location = var.region

  remove_default_node_pool = true
  initial_node_count       = 1

  network    = google_compute_network.main.name
  subnetwork = google_compute_subnetwork.private.name

  ip_allocation_policy {
    cluster_secondary_range_name  = "pods"
    services_secondary_range_name = "services"
  }

  private_cluster_config {
    enable_private_nodes    = true
    enable_private_endpoint = false
    master_ipv4_cidr_block  = "172.16.0.0/28"
  }

  workload_identity_config {
    workload_pool = "${var.project_id}.svc.id.goog"
  }

  release_channel {
    channel = "STABLE"
  }
}

resource "google_container_node_pool" "primary" {
  name       = "primary"
  location   = var.region
  cluster    = google_container_cluster.main.name
  node_count = 3

  autoscaling {
    min_node_count = 1
    max_node_count = 10
  }

  node_config {
    machine_type = "e2-standard-4"
    disk_size_gb = 100

    oauth_scopes = [
      "https://www.googleapis.com/auth/cloud-platform"
    ]

    workload_metadata_config {
      mode = "GKE_METADATA"
    }
  }
}

Cloud SQL

resource "google_sql_database_instance" "main" {
  name             = "${var.project}-db"
  database_version = "POSTGRES_15"
  region           = var.region

  settings {
    tier              = "db-custom-4-16384"
    availability_type = var.environment == "prod" ? "REGIONAL" : "ZONAL"

    backup_configuration {
      enabled                        = true
      point_in_time_recovery_enabled = true
      start_time                     = "03:00"
    }

    ip_configuration {
      ipv4_enabled    = false
      private_network = google_compute_network.main.id
    }
  }

  deletion_protection = var.environment == "prod"
}

IAM

resource "google_service_account" "app" {
  account_id   = "${var.project}-app"
  display_name = "Application Service Account"
}

resource "google_project_iam_member" "app_storage" {
  project = var.project_id
  role    = "roles/storage.objectViewer"
  member  = "serviceAccount:${google_service_account.app.email}"
}

# Workload Identity binding
resource "google_service_account_iam_member" "workload_identity" {
  service_account_id = google_service_account.app.name
  role               = "roles/iam.workloadIdentityUser"
  member             = "serviceAccount:${var.project_id}.svc.id.goog[${var.namespace}/${var.k8s_sa_name}]"
}

Troubleshooting

Error	Cause	Solution
Permission denied	Missing IAM role	Add required role
Quota exceeded	Resource limit	Request quota increase
Network not found	Wrong project/name	Check network reference

Usage

Skill("terraform-gcp")

Related

• Agent: 08-terraform-advanced (SECONDARY_BOND)