GSP155

Overview

In this hands-on lab you learn how to set up a Layer 7 (L7) application load balancer on Compute Engine virtual machines (VMs). L7 load balancers can understand HTTP(S) protocols, allowing them to make routing decisions based on parameters like URL, headers, cookies, and the content of the request. This allows for improved application performance and responsiveness.

There are several ways you can load balance on Google Cloud. This lab takes you through the setup of the following load balancers:

• Application Load Balancer

You are encouraged to type the commands yourself, which can help you learn the core concepts. Many labs include a code block that contains the required commands. You can easily copy and paste the commands from the code block into the appropriate places during the lab.

Objectives

In this lab, you learn how to perform the following tasks:

• Configure the default region and zone for your resources.
• Create an Application Load Balancer.
• Test the traffic to your insances.

Setup and requirements

Before you click the Start Lab button

Read these instructions. Labs are timed and you cannot pause them. The timer, which starts when you click Start Lab, shows how long Google Cloud resources are made available to you.

This hands-on lab lets you do the lab activities in a real cloud environment, not in a simulation or demo environment. It does so by giving you new, temporary credentials you use to sign in and access Google Cloud for the duration of the lab.

To complete this lab, you need:

• Access to a standard internet browser (Chrome browser recommended).

Note: Use an Incognito (recommended) or private browser window to run this lab. This prevents conflicts between your personal account and the student account, which may cause extra charges incurred to your personal account.

• Time to complete the lab—remember, once you start, you cannot pause a lab.

Note: Use only the student account for this lab. If you use a different Google Cloud account, you may incur charges to that account.

How to start your lab and sign in to the Google Cloud console

1. Click the Start Lab button. If you need to pay for the lab, a dialog opens for you to select your payment method. On the left is the Lab Details pane with the following:

   • The Open Google Cloud console button
   • Time remaining
   • The temporary credentials that you must use for this lab
   • Other information, if needed, to step through this lab

2. Click Open Google Cloud console (or right-click and select Open Link in Incognito Window if you are running the Chrome browser).

   The lab spins up resources, and then opens another tab that shows the Sign in page.

   Tip: Arrange the tabs in separate windows, side-by-side.

   Note: If you see the Choose an account dialog, click Use Another Account.

3. If necessary, copy the Username below and paste it into the Sign in dialog.

   {{{user_0.username | "Username"}}}

   You can also find the Username in the Lab Details pane.

4. Click Next.

5. Copy the Password below and paste it into the Welcome dialog.

   {{{user_0.password | "Password"}}}

   You can also find the Password in the Lab Details pane.

6. Click Next.

   Important: You must use the credentials the lab provides you. Do not use your Google Cloud account credentials. Note: Using your own Google Cloud account for this lab may incur extra charges.

7. Click through the subsequent pages:

   • Accept the terms and conditions.
   • Do not add recovery options or two-factor authentication (because this is a temporary account).
   • Do not sign up for free trials.

After a few moments, the Google Cloud console opens in this tab.

Note: To access Google Cloud products and services, click the Navigation menu or type the service or product name in the Search field.

Activate Cloud Shell

Cloud Shell is a virtual machine that is loaded with development tools. It offers a persistent 5GB home directory and runs on the Google Cloud. Cloud Shell provides command-line access to your Google Cloud resources.

1. Click Activate Cloud Shell at the top of the Google Cloud console.

2. Click through the following windows:

   • Continue through the Cloud Shell information window.
   • Authorize Cloud Shell to use your credentials to make Google Cloud API calls.

When you are connected, you are already authenticated, and the project is set to your Project_ID, . The output contains a line that declares the Project_ID for this session:

Your Cloud Platform project in this session is set to {{{project_0.project_id | "PROJECT_ID"}}}

gcloud is the command-line tool for Google Cloud. It comes pre-installed on Cloud Shell and supports tab-completion.

3. (Optional) You can list the active account name with this command:

gcloud auth list

4. Click Authorize.

Output:

ACTIVE: * ACCOUNT: {{{user_0.username | "ACCOUNT"}}} To set the active account, run: $ gcloud config set account `ACCOUNT`

5. (Optional) You can list the project ID with this command:

gcloud config list project

Output:

[core] project = {{{project_0.project_id | "PROJECT_ID"}}} Note: For full documentation of gcloud, in Google Cloud, refer to the gcloud CLI overview guide.

Task 1. Set the default region and zone for all resources

1. Set the default region:

   gcloud config set compute/region {{{project_0.default_region | Region}}}

2. In Cloud Shell, set the default zone:

   gcloud config set compute/zone {{{project_0.default_zone | Zone}}}

   Learn more about choosing zones and regions in Compute Engine's Regions and zones documentation.

Task 2. Create multiple web server instances

For this load balancing scenario, you create three Compute Engine VM instances and install Apache on them, then add a firewall rule that allows HTTP traffic to reach the instances.

The code provided sets the zone to . Setting the tags field lets you reference these instances all at once, such as with a firewall rule. These commands also install Apache on each instance and gives each instance a unique home page.

1. Create a virtual machine, www1, in your default zone using the following code:

   gcloud compute instances create www1 \ --zone={{{project_0.default_zone | Zone}}} \ --tags=network-lb-tag \ --machine-type=e2-small \ --image-family=debian-11 \ --image-project=debian-cloud \ --metadata=startup-script='#!/bin/bash apt-get update apt-get install apache2 -y service apache2 restart echo "

   Web Server: www1

   " | tee /var/www/html/index.html'

2. Create a virtual machine, www2, in your default zone using the following code:

   gcloud compute instances create www2 \ --zone={{{project_0.default_zone | Zone}}} \ --tags=network-lb-tag \ --machine-type=e2-small \ --image-family=debian-11 \ --image-project=debian-cloud \ --metadata=startup-script='#!/bin/bash apt-get update apt-get install apache2 -y service apache2 restart echo "

   Web Server: www2

   " | tee /var/www/html/index.html'

3. Create a virtual machine, www3, in your default zone.

   gcloud compute instances create www3 \ --zone={{{project_0.default_zone | Zone}}} \ --tags=network-lb-tag \ --machine-type=e2-small \ --image-family=debian-11 \ --image-project=debian-cloud \ --metadata=startup-script='#!/bin/bash apt-get update apt-get install apache2 -y service apache2 restart echo "

   Web Server: www3

   " | tee /var/www/html/index.html'

4. Create a firewall rule to allow external traffic to the VM instances:

   gcloud compute firewall-rules create www-firewall-network-lb \ --target-tags network-lb-tag --allow tcp:80

Now you need to get the external IP addresses of your instances and verify that they are running.

5. Run the following to list your instances. You'll see their IP addresses in the EXTERNAL_IP column:

   gcloud compute instances list

6. Verify that each instance is running with curl, replacing [IP_ADDRESS] with the external IP address for each of your VMs:

   curl http://[IP_ADDRESS]

   Click Check my progress to verify that you've created a group of web servers. Create multiple web server instances

Task 3. Create an Application Load Balancer

Application Load Balancing is implemented on Google Front End (GFE). GFEs are distributed globally and operate together using Google's global network and control plane. You can configure URL rules to route some URLs to one set of instances and route other URLs to other instances.

Requests are always routed to the instance group that is closest to the user, if that group has enough capacity and is appropriate for the request. If the closest group does not have enough capacity, the request is sent to the closest group that does have capacity.

To set up a load balancer with a Compute Engine backend, your VMs need to be in an instance group. The managed instance group provides VMs running the backend servers of an external application load balancer. For this lab, backends serve their own hostnames.

1. First, create the load balancer template:

   gcloud compute instance-templates create lb-backend-template \ --region={{{project_0.default_region | Region}}} \ --network=default \ --subnet=default \ --tags=allow-health-check \ --machine-type=e2-medium \ --image-family=debian-11 \ --image-project=debian-cloud \ --metadata=startup-script='#!/bin/bash apt-get update apt-get install apache2 -y a2ensite default-ssl a2enmod ssl vm_hostname="$(curl -H "Metadata-Flavor:Google" \ http://169.254.169.254/computeMetadata/v1/instance/name)" echo "Page served from: $vm_hostname" | \ tee /var/www/html/index.html systemctl restart apache2'

   Managed instance groups (MIGs) let you operate apps on multiple identical VMs. You can make your workloads scalable and highly available by taking advantage of automated MIG services, including: autoscaling, autohealing, regional (multiple zone) deployment, and automatic updating.

2. Create a managed instance group based on the template:

   gcloud compute instance-groups managed create lb-backend-group \ --template=lb-backend-template --size=2 --zone={{{project_0.default_zone | Zone}}}

3. Create the fw-allow-health-check firewall rule.

   gcloud compute firewall-rules create fw-allow-health-check \ --network=default \ --action=allow \ --direction=ingress \ --source-ranges=130.211.0.0/22,35.191.0.0/16 \ --target-tags=allow-health-check \ --rules=tcp:80 Note: The ingress rule allows traffic from the Google Cloud health checking systems (130.211.0.0/22 and 35.191.0.0/16). This lab uses the target tag allow-health-check to identify the VMs

4. Now that the instances are up and running, set up a global static external IP address that your customers use to reach your load balancer:

   gcloud compute addresses create lb-ipv4-1 \ --ip-version=IPV4 \ --global

   Notice that the IPv4 address that was reserved:

   gcloud compute addresses describe lb-ipv4-1 \ --format="get(address)" \ --global Note: Save this IP address, as you need to refer to it later in this lab.

5. Create a health check for the load balancer (to ensure that only healthy backends are sent traffic):

   gcloud compute health-checks create http http-basic-check \ --port 80

6. Create a backend service:

   gcloud compute backend-services create web-backend-service \ --protocol=HTTP \ --port-name=http \ --health-checks=http-basic-check \ --global

7. Add your instance group as the backend to the backend service:

   gcloud compute backend-services add-backend web-backend-service \ --instance-group=lb-backend-group \ --instance-group-zone={{{project_0.default_zone | Zone}}} \ --global

8. Create a URL map to route the incoming requests to the default backend service:

   gcloud compute url-maps create web-map-http \ --default-service web-backend-service Note: URL map is a Google Cloud configuration resource used to route requests to backend services or backend buckets. For example, with an external Application Load Balancer, you can use a single URL map to route requests to different destinations based on the rules configured in the URL map:
   • Requests for https://example.com/video go to one backend service.
   • Requests for https://example.com/audio go to a different backend service.
   • Requests for https://example.com/images go to a Cloud Storage backend bucket.
   • Requests for any other host and path combination go to a default backend service.

9. Create a target HTTP proxy to route requests to your URL map:

   gcloud compute target-http-proxies create http-lb-proxy \ --url-map web-map-http

10. Create a global forwarding rule to route incoming requests to the proxy:

    gcloud compute forwarding-rules create http-content-rule \ --address=lb-ipv4-1\ --global \ --target-http-proxy=http-lb-proxy \ --ports=80

Note: A forwarding rule and its corresponding IP address represent the frontend configuration of a Google Cloud load balancer. Learn more about the general understanding of forwarding rules from the Forwarding rules overview guide.

Click Check my progress to verify that you've created an L7 Application Load Balancer. Create an Application Load Balancer

Task 4. Test traffic sent to your instances

1. On the Google Cloud console in the Search field type Load balancing, then choose Load balancing from the search results.

2. Click on the load balancer that you just created, web-map-http.

3. In the Backend section, click on the name of the backend and confirm that the VMs are Healthy. If they are not healthy, wait a few moments and try reloading the page.

4. When the VMs are healthy, test the load balancer using a web browser, going to http://IP_ADDRESS/, replacing IP_ADDRESS with the load balancer's IP address that you copied previously.

Note: This may take three to five minutes. If you do not connect, wait a minute, and then reload the browser.

Your browser should render a page with content showing the name of the instance that served the page, along with its zone (for example, Page served from: lb-backend-group-xxxx).

Click Check my progress to test traffic sent to your instances. Test the load balancer using a web browser

Congratulations!

In this lab, you have built an application load balancer and practiced using instance templates and managed instance groups to send traffic to web server instances.

Next steps / Learn more

Additional load balancer documentation:

• Set up a classic Application Load Balancer with a managed instance group backend
• External Application Load Balancer overview

Google Cloud provides health checking mechanisms that determine whether backend instances respond properly to traffic.

• Refer to the Creating health checks documentation.

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Manual Last Updated July 18, 2025

Lab Last Tested July 18, 2025

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