Merge pull request hashicorp#2914 from TimeIncOSS/google-cloud-2-tier-example

google: Add an example of a two-tier app

Author: catsby

examples/google-two-tier/.gitignore

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+terraform.tfvars

examples/google-two-tier/README.md

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+# Basic Two-Tier Architecture in Google Cloud
+
+This provides a template for running a simple two-tier architecture on Google Cloud.
+The premise is that you have stateless app servers running behind
+a load balancer serving traffic.
+
+To simplify the example, this intentionally ignores deploying and
+getting your application onto the servers. However, you could do so either via
+[startup script](http://terraform.io/docs/providers/google/r/compute_instance.html#metadata_startup_script) or
+[provisioners](https://www.terraform.io/docs/provisioners/) and a configuration
+management tool, or by pre-baking configured images with
+[Packer](https://packer.io/docs/builders/googlecompute.html).
+
+After you run `terraform apply` on this configuration, it will
+automatically output the public IP address of the load balancer.
+After your instance registers, the LB should respond with a simple header:
+
+```html
+<h1>Welcome to instance 0</h1>
+```
+
+The index may differ once you increase `count` of `google_compute_instance`
+(i.e. provision more instances).
+
+To run, configure your Google Cloud provider as described in
+
+https://www.terraform.io/docs/providers/google/index.html
+
+Run with a command like this:
+
+```
+terraform apply \
+	-var="region=us-central1" \
+	-var="region_zone=us-central1-f" \
+	-var="project_name=my-project-id-123" \
+	-var="account_file_path=~/.gcloud/Terraform.json" \
+	-var="public_key_path=~/.ssh/gcloud_id_rsa.pub" \
+	-var="private_key_path=~/.ssh/gcloud_id_rsa"
+```

examples/google-two-tier/main.tf

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+# See https://cloud.google.com/compute/docs/load-balancing/network/example
+
+provider "google" {
+    region = "${var.region}"
+    project = "${var.project_name}"
+    account_file = "${file(var.account_file_path)}"
+}
+
+resource "google_compute_http_health_check" "default" {
+    name = "tf-www-basic-check"
+    request_path = "/"
+    check_interval_sec = 1
+    healthy_threshold = 1
+    unhealthy_threshold = 10
+    timeout_sec = 1
+}
+
+resource "google_compute_target_pool" "default" {
+    name = "tf-www-target-pool"
+    instances = ["${google_compute_instance.www.*.self_link}"]
+    health_checks = ["${google_compute_http_health_check.default.name}"]
+}
+
+resource "google_compute_forwarding_rule" "default" {
+    name = "tf-www-forwarding-rule"
+    target = "${google_compute_target_pool.default.self_link}"
+    port_range = "80"
+}
+
+resource "google_compute_instance" "www" {
+    count = 3
+
+    name = "tf-www-${count.index}"
+    machine_type = "n1-standard-1"
+    zone = "${var.region_zone}"
+    tags = ["www-node"]
+
+    disk {
+        image = "ubuntu-os-cloud/ubuntu-1204-precise-v20150625"
+    }
+
+    network_interface {
+        network = "default"
+        access_config {
+            # Ephemeral
+        }
+    }
+
+    metadata {
+        sshKeys = "ubuntu:${file("~/.ssh/gcloud_id_rsa.pub")}"
+        startup-script = <<SCRIPT
+apt-get -y update
+apt-get -y install nginx
+HOSTNAME=$(hostname | tr -d "\n")
+IP=$(curl -s -H "Metadata-Flavor:Google" http://metadata/computeMetadata/v1/instance/network-interfaces/0/ip)
+echo "Welcome to ${count.index} - $HOSTNAME ($IP)" > /usr/share/nginx/www/index.html
+service nginx start
+SCRIPT
+    }
+
+    service_account {
+        scopes = ["https://www.googleapis.com/auth/compute.readonly"]
+    }
+}
+
+resource "google_compute_firewall" "default" {
+    name = "tf-www-firewall"
+    network = "default"
+
+    allow {
+        protocol = "tcp"
+        ports = ["80"]
+    }
+
+    source_ranges = ["0.0.0.0/0"]
+    target_tags = ["www-node"]
+}

examples/google-two-tier/output.tf

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+output "pool_public_ip" {
+    value = "${google_compute_forwarding_rule.default.ip_address}"
+}
+
+output "instance_ips" {
+	value = "${join(" ", google_compute_instance.www.*.network_interface.0.access_config.0.nat_ip)}"
+}

examples/google-two-tier/terraform.tfvars.example

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+region = "us-central1"
+region_zone = "us-central1-a"
+project_name = "my-project-id-123"
+account_file_path = "~/.gcloud/Terraform.json"
+public_key_path = "~/.ssh/gcloud_id_rsa.pub"
+private_key_path = "~/.ssh/gcloud_id_rsa"

examples/google-two-tier/variables.tf

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+variable "region" {
+	default = "us-central1"
+}
+
+variable "region_zone" {
+	default = "us-central1-f"
+}
+
+variable "project_name" {
+	description = "The ID of the Google Cloud project"
+}
+
+variable "account_file_path" {
+	description = "Path to the JSON file used to describe your account credentials"
+}