Terraform examples for external Application Load Balancers

This page provides Terraform modules that you can use to deploy external Application Load Balancers. Depending on your preferred backend type, use one of the following examples to deploy a sample external Application Load Balancer.

If you are new to using Terraform for Google Cloud, see Get started with Terraform.

External Application Load Balancer with managed instance group (MIG) backends

You can use a Terraform module to bring up an external HTTP load balancer with Compute Engine backends.

This module creates multiple Terraform resources, including a VPC network and subnetworks, Cloud Routers, all of the necessary load balancer components, and backend instance groups. For more information, download or clone the repository and run the terraform plan command in the /terraform-google-lb-http/examples/multi-mig-http-lb directory.

For more information about this example and to learn how to run it, see the README on GitHub.

module "gce-lb-http" {
  source  = "terraform-google-modules/lb-http/google"
  version = "~> 12.0"
  name    = var.network_prefix
  project = var.project
  target_tags = [
    "${var.network_prefix}-group1",
    module.cloud-nat-group1.router_name,
    "${var.network_prefix}-group2",
    module.cloud-nat-group2.router_name
  ]
  firewall_networks = [google_compute_network.default.name]

  backends = {
    default = {

      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = {
        request_path = "/"
        port         = 80
      }

      log_config = {
        enable      = true
        sample_rate = 1.0
      }

      groups = [
        {
          group = module.mig1.instance_group
        },
        {
          group = module.mig2.instance_group
        },
      ]

      iap_config = {
        enable = false
      }
    }
  }
}

External Application Load Balancer with MIG backend and custom headers

You can use Terraform resources to bring up an external Application Load Balancer with a Cloud CDN-enabled backend service and custom request and response headers.

For detailed information about the load balancer setup, see the primary setup guide.

# VPC
resource "google_compute_network" "default" {
  name                    = "l7-xlb-network"
  provider                = google-beta
  auto_create_subnetworks = false
}

# backend subnet
resource "google_compute_subnetwork" "default" {
  name          = "l7-xlb-subnet"
  provider      = google-beta
  ip_cidr_range = "10.0.1.0/24"
  region        = "us-central1"
  network       = google_compute_network.default.id
}

# reserved IP address
resource "google_compute_global_address" "default" {
  provider = google-beta
  name     = "l7-xlb-static-ip"
}

# forwarding rule
resource "google_compute_global_forwarding_rule" "default" {
  name                  = "l7-xlb-forwarding-rule"
  provider              = google-beta
  ip_protocol           = "TCP"
  load_balancing_scheme = "EXTERNAL"
  port_range            = "80"
  target                = google_compute_target_http_proxy.default.id
  ip_address            = google_compute_global_address.default.id
}

# http proxy
resource "google_compute_target_http_proxy" "default" {
  name     = "l7-xlb-target-http-proxy"
  provider = google-beta
  url_map  = google_compute_url_map.default.id
}

# url map
resource "google_compute_url_map" "default" {
  name            = "l7-xlb-url-map"
  provider        = google-beta
  default_service = google_compute_backend_service.default.id
}

# backend service with custom request and response headers
resource "google_compute_backend_service" "default" {
  name                    = "l7-xlb-backend-service"
  provider                = google-beta
  protocol                = "HTTP"
  port_name               = "my-port"
  load_balancing_scheme   = "EXTERNAL"
  timeout_sec             = 10
  enable_cdn              = true
  custom_request_headers  = ["X-Client-Geo-Location: {client_region_subdivision}, {client_city}"]
  custom_response_headers = ["X-Cache-Hit: {cdn_cache_status}"]
  health_checks           = [google_compute_health_check.default.id]
  backend {
    group           = google_compute_instance_group_manager.default.instance_group
    balancing_mode  = "UTILIZATION"
    capacity_scaler = 1.0
  }
}

# instance template
resource "google_compute_instance_template" "default" {
  name         = "l7-xlb-mig-template"
  provider     = google-beta
  machine_type = "e2-small"
  tags         = ["allow-health-check"]

  network_interface {
    network    = google_compute_network.default.id
    subnetwork = google_compute_subnetwork.default.id
    access_config {
      # add external ip to fetch packages
    }
  }
  disk {
    source_image = "debian-cloud/debian-12"
    auto_delete  = true
    boot         = true
  }

  # install nginx and serve a simple web page
  metadata = {
    startup-script = <<-EOF1
      #! /bin/bash
      set -euo pipefail

      export DEBIAN_FRONTEND=noninteractive
      apt-get update
      apt-get install -y nginx-light jq

      NAME=$(curl -H "Metadata-Flavor: Google" "http://metadata.google.internal/computeMetadata/v1/instance/hostname")
      IP=$(curl -H "Metadata-Flavor: Google" "http://metadata.google.internal/computeMetadata/v1/instance/network-interfaces/0/ip")
      METADATA=$(curl -f -H "Metadata-Flavor: Google" "http://metadata.google.internal/computeMetadata/v1/instance/attributes/?recursive=True" | jq 'del(.["startup-script"])')

      cat <<EOF > /var/www/html/index.html
      <pre>
      Name: $NAME
      IP: $IP
      Metadata: $METADATA
      </pre>
      EOF
    EOF1
  }
  lifecycle {
    create_before_destroy = true
  }
}

# health check
resource "google_compute_health_check" "default" {
  name     = "l7-xlb-hc"
  provider = google-beta
  http_health_check {
    port_specification = "USE_SERVING_PORT"
  }
}

# MIG
resource "google_compute_instance_group_manager" "default" {
  name     = "l7-xlb-mig1"
  provider = google-beta
  zone     = "us-central1-c"
  named_port {
    name = "http"
    port = 8080
  }
  version {
    instance_template = google_compute_instance_template.default.id
    name              = "primary"
  }
  base_instance_name = "vm"
  target_size        = 2
}

# allow access from health check ranges
resource "google_compute_firewall" "default" {
  name          = "l7-xlb-fw-allow-hc"
  provider      = google-beta
  direction     = "INGRESS"
  network       = google_compute_network.default.id
  source_ranges = ["130.211.0.0/22", "35.191.0.0/16"]
  allow {
    protocol = "tcp"
  }
  target_tags = ["allow-health-check"]
}

External Application Load Balancer with a backend bucket and MIGs

You can use a Terraform module to bring up an external HTTPS load balancer with Compute Engine backends plus static assets being served from a Cloud Storage bucket.

This module creates multiple Terraform resources, including a VPC network and subnetworks, a Cloud Storage bucket and object, Cloud Routers, a self-signed SSL certificate, all of the necessary load balancer components, and backend instance groups. For more information, download or clone the repository and run the terraform plan command in the /terraform-google-lb-http/examples/multi-backend-multi-mig-bucket-https-lb directory.

For more information about this example and to learn how to run it, see the README in GitHub.

module "gce-lb-https" {
  source  = "terraform-google-modules/lb-http/google"
  version = "~> 12.0"
  name    = var.network_name
  project = var.project
  target_tags = [
    "${var.network_name}-group1",
    module.cloud-nat-group1.router_name,
    "${var.network_name}-group2",
    module.cloud-nat-group2.router_name,
    "${var.network_name}-group3",
    module.cloud-nat-group3.router_name
  ]
  firewall_networks = [google_compute_network.default.self_link]
  url_map           = google_compute_url_map.ml-bkd-ml-mig-bckt-s-lb.self_link
  create_url_map    = false
  ssl               = true
  private_key       = tls_private_key.example.private_key_pem
  certificate       = tls_self_signed_cert.example.cert_pem

  backends = {
    default = {
      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = local.health_check
      log_config = {
        enable      = true
        sample_rate = 1.0
      }
      groups = [
        {
          group = module.mig1.instance_group
        },
        {
          group = module.mig2.instance_group
        },
        {
          group = module.mig3.instance_group
        },
      ]

      iap_config = {
        enable = false
      }
    }

    mig1 = {
      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = local.health_check
      log_config = {
        enable      = true
        sample_rate = 1.0
      }
      groups = [
        {
          group = module.mig1.instance_group
        },
      ]

      iap_config = {
        enable = false
      }
    }

    mig2 = {
      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = local.health_check
      log_config = {
        enable      = true
        sample_rate = 1.0
      }
      groups = [
        {
          group = module.mig2.instance_group
        },
      ]

      iap_config = {
        enable = false
      }
    }

    mig3 = {
      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = local.health_check
      log_config = {
        enable      = true
        sample_rate = 1.0
      }
      groups = [
        {
          group = module.mig3.instance_group
        },
      ]

      iap_config = {
        enable = false
      }
    }
  }
}

resource "google_compute_url_map" "ml-bkd-ml-mig-bckt-s-lb" {
  // note that this is the name of the load balancer
  name            = var.network_name
  default_service = module.gce-lb-https.backend_services["default"].self_link

  host_rule {
    hosts        = ["*"]
    path_matcher = "allpaths"
  }

  path_matcher {
    name            = "allpaths"
    default_service = module.gce-lb-https.backend_services["default"].self_link

    path_rule {
      paths = [
        "/group1",
        "/group1/*"
      ]
      service = module.gce-lb-https.backend_services["mig1"].self_link
    }

    path_rule {
      paths = [
        "/group2",
        "/group2/*"
      ]
      service = module.gce-lb-https.backend_services["mig2"].self_link
    }

    path_rule {
      paths = [
        "/group3",
        "/group3/*"
      ]
      service = module.gce-lb-https.backend_services["mig3"].self_link
    }

    path_rule {
      paths = [
        "/assets",
        "/assets/*"
      ]
      service = google_compute_backend_bucket.assets.self_link
    }
  }
}

resource "google_compute_backend_bucket" "assets" {
  name        = random_id.assets-bucket.hex
  description = "Contains static resources for example app"
  bucket_name = google_storage_bucket.assets.name
  enable_cdn  = true
}

resource "google_storage_bucket" "assets" {
  name     = random_id.assets-bucket.hex
  location = "US"

  // delete bucket and contents on destroy.
  force_destroy = true
}

// The image object in Cloud Storage.
// Note that the path in the bucket matches the paths in the url map path rule above.
resource "google_storage_bucket_object" "image" {
  name         = "assets/gcp-logo.svg"
  content      = file("gcp-logo.svg")
  content_type = "image/svg+xml"
  bucket       = google_storage_bucket.assets.name
}

// Make object public readable.
resource "google_storage_object_acl" "image-acl" {
  bucket         = google_storage_bucket.assets.name
  object         = google_storage_bucket_object.image.name
  predefined_acl = "publicRead"
}

External Application Load Balancer with a Cloud Run backend

You can use a Terraform module to bring up an external HTTPS load balancer with a Cloud Run backend.

This module creates multiple Terraform resources, including a Cloud Run service, a self-signed SSL certificate, a URL map that sets up an HTTP-to-HTTPs redirect, all of the necessary load balancer components, and backend instance groups. For more information, download or clone the repository and run the terraform plan command in the /terraform-google-lb-http/examples/cloudrun directory.

For more information about this example and to learn how to run it, see the README in GitHub.

module "lb-http" {
  source  = "terraform-google-modules/lb-http/google//modules/serverless_negs"
  version = "~> 12.0"

  name    = var.lb_name
  project = var.project_id

  ssl                             = var.ssl
  managed_ssl_certificate_domains = [var.domain]
  https_redirect                  = var.ssl
  labels                          = { "example-label" = "cloud-run-example" }

  backends = {
    default = {
      description = null
      groups = [
        {
          group = google_compute_region_network_endpoint_group.serverless_neg.id
        }
      ]
      enable_cdn = false

      iap_config = {
        enable = false
      }
      log_config = {
        enable = false
      }
    }
  }
}

resource "google_compute_region_network_endpoint_group" "serverless_neg" {
  provider              = google-beta
  name                  = "serverless-neg"
  network_endpoint_type = "SERVERLESS"
  region                = var.region
  cloud_run {
    service = google_cloud_run_service.default.name
  }
}

resource "google_cloud_run_service" "default" {
  name     = "example"
  location = var.region
  project  = var.project_id

  template {
    spec {
      containers {
        image = "gcr.io/cloudrun/hello"
      }
    }
  }
  metadata {
    annotations = {
      # For valid annotation values and descriptions, see
      # https://cloud.google.com/sdk/gcloud/reference/run/deploy#--ingress
      "run.googleapis.com/ingress" = "all"
    }
  }
}

resource "google_cloud_run_service_iam_member" "public-access" {
  location = google_cloud_run_service.default.location
  project  = google_cloud_run_service.default.project
  service  = google_cloud_run_service.default.name
  role     = "roles/run.invoker"
  member   = "allUsers"
}

External Application Load Balancer with an HTTP-to-HTTPS redirect

You can use a Terraform module to bring up an external HTTPS load balancer with HTTP-to-HTTPS redirection.

This module creates multiple Terraform resources, including a VPC network and subnetwork, a self-signed SSL certificate, a Cloud Router, all of the necessary load balancer components, and a backend instance group. For more information, download or clone the repository and run the terraform plan command in the /terraform-google-lb-http/examples/https-redirect directory.

For more information about this example and to learn how to run it, see the README in GitHub.

module "gce-lb-http" {
  source            = "terraform-google-modules/lb-http/google"
  version           = "~> 12.0"
  name              = "ci-https-redirect"
  project           = var.project
  target_tags       = [var.network_name]
  firewall_networks = [google_compute_network.default.name]
  ssl               = true
  ssl_certificates  = [google_compute_ssl_certificate.example.self_link]
  https_redirect    = true

  backends = {
    default = {
      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = {
        request_path = "/"
        port         = 80
      }

      log_config = {
        enable = false
      }

      groups = [
        {
          group = module.mig.instance_group
        }
      ]
      iap_config = {
        enable = false
      }
    }
  }
}

External Application Load Balancer with Shared VPC

You can use a Terraform module to bring up an external Application Load Balancer in a Shared VPC setup.

This module creates multiple Terraform resources, including a VPC network and subnetwork, a Cloud Router, all of the necessary load balancer components, and a backend instance group. For more information, download or clone the repository and run the terraform plan command in the /terraform-google-lb-http/examples/shared-vpc directory.

For more information about this example and to learn how to run it, see the README in GitHub.

module "gce-lb-http" {
  source  = "terraform-google-modules/lb-http/google"
  version = "~> 12.0"

  name              = "group-http-lb"
  project           = var.service_project
  target_tags       = ["allow-shared-vpc-mig"]
  firewall_projects = [var.host_project]
  firewall_networks = [var.network]

  backends = {
    default = {
      protocol    = "HTTP"
      port        = 80
      port_name   = "http"
      timeout_sec = 10
      enable_cdn  = false

      health_check = {
        request_path = "/"
        port         = 80
      }

      log_config = {
        enable      = true
        sample_rate = 1.0
      }

      groups = [
        {
          group = module.mig.instance_group
        }
      ]

      iap_config = {
        enable = false
      }
    }
  }
}