How to Setup HTTP Load balancer in Google Cloud (GCP)



                                             HTTP Load Balancer

Create an HTTP load balancer

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 HTTP load balancer.

Create the load balancer template:

gcloud compute instance-templates create lb-backend-template \
   --region=us-central1 \
   --network=default \
   --subnet=default \
   --tags=allow-health-check \
   --image-family=debian-9 \
   --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" \"
     echo "Page served from: $vm_hostname" | \
     tee /var/www/html/index.html
     systemctl restart apache2'

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=us-central1-a

Create the fw-allow-health-check firewall rule. This is an ingress rule that allows traffic from the Google Cloud health checking systems ( and This lab uses the target tag allow-health-check to identify the VMs.

gcloud compute firewall-rules create fw-allow-health-check \
    --network=default \
    --action=allow \
    --direction=ingress \
    --source-ranges=, \
    --target-tags=allow-health-check \

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 \

Note the IPv4 address that was reserved:

gcloud compute addresses describe lb-ipv4-1 \
    --format="get(address)" \

Create a healthcheck for the load balancer:

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

Create a backend service:

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

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=us-central1-a \

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

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

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

    gcloud compute forwarding-rules create http-content-rule \
        --global \
        --target-http-proxy=http-lb-proxy \

Share on Google Plus

About Ashadullah Shawon

I am Ashadullah Shawon. I am a Software Engineer. I studied Computer Science and Engineering (CSE) at RUET. I Like To Share Knowledge. Learn More: Click Here
    Blogger Comment
    Facebook Comment


Post a Comment