如何使用terraform对google计算实例进行负载均衡？

provider "google" {
  project = "your-project-id"
  region  = "us-central1"
}

resource "google_compute_instance" "example_instance" {
  name         = "example-instance"
  machine_type = "n1-standard-1"
  zone         = "us-central1-a"
  # ...
}

resource "google_compute_backend_service" "example_backend_service" {
  name        = "example-backend-service"
  protocol    = "HTTP"
  port_name   = "http"
  timeout_sec = 10

  backend {
    group = google_compute_instance_group.example_group.self_link
  }
}

resource "google_compute_url_map" "example_url_map" {
  name        = "example-url-map"
  default_service = google_compute_backend_service.example_backend_service.self_link

  host_rule {
    hosts = ["example.com"]
    path_matcher = "allpaths"
  }

  path_matcher {
    name = "allpaths"
    default_service = google_compute_backend_service.example_backend_service.self_link
  }
}

resource "google_compute_instance_group" "example_group" {
  name        = "example-group"
  zone        = "us-central1-a"
  instances   = [google_compute_instance.example_instance.self_link]
}

resource "google_compute_global_forwarding_rule" "example_forwarding_rule" {
  name       = "example-forwarding-rule"
  target     = google_compute_backend_service.example_backend_service.self_link
  port_range = "80"
}