Set Up Network and HTTP Load Balancers
Set the default region and zone for all resources
- In Cloud Shell, set the default zone:
gcloud config set compute/zone us-central1-a
- Set the default region:
gcloud config set compute/region us-central
Create multiple web server instances
- Create three new virtual machines in your default zone and give them all the same tag. The code provided sets the zone toÂ
us-central1-a. 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 give each instance a unique home page.gcloud compute instances create www1 \ --image-family debian-9 \ --image-project debian-cloud \ --zone us-central1-a \ --tags network-lb-tag \ --metadata startup-script="#! /bin/bash sudo apt-get update sudo apt-get install apache2 -y sudo service apache2 restart echo '<!doctype html><html><body><h1>www1</h1></body></html>' | tee /var/www/html/index.html"gcloud compute instances create www2 \ --image-family debian-9 \ --image-project debian-cloud \ --zone us-central1-a \ --tags network-lb-tag \ --metadata startup-script="#! /bin/bash sudo apt-get update sudo apt-get install apache2 -y sudo service apache2 restart echo '<!doctype html><html><body><h1>www2</h1></body></html>' | tee /var/www/html/index.html"gcloud compute instances create www3 \ --image-family debian-9 \ --image-project debian-cloud \ --zone us-central1-a \ --tags network-lb-tag \ --metadata startup-script="#! /bin/bash sudo apt-get update sudo apt-get install apache2 -y sudo service apache2 restart echo '<!doctype html><html><body><h1>www3</h1></body></html>' | tee /var/www/html/index.html"
- 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.
- Run the following to list your instances. You’ll see their IP addresses in theÂ
EXTERNAL_IPcolumn:
gcloud compute instances list
- Verify that each instance is running withÂ
curl, replacing [IP_ADDRESS] with the IP address for each of your VMs:
curl http://[IP_ADDRESS]
Configure the load balancing service
- Create a static external IP address for your load balancer:
gcloud compute addresses create network-lb-ip-1 \ --region us-central1
- Add a legacy HTTP health check resource:
gcloud compute http-health-checks create basic-check
- Add a target pool in the same region as your instances. Run the following to create the target pool and use the health check, which is required for the service to function:
gcloud compute target-pools create www-pool \ --region us-central1 --http-health-check basic-check
- Add the instances to the pool:
gcloud compute target-pools add-instances www-pool \ --instances www1,www2,www3
- Add a forwarding rule:
gcloud compute forwarding-rules create www-rule \ --region us-central1 \ --ports 80 \ --address network-lb-ip-1 \ --target-pool www-pool
Sending traffic to your instances
- Enter the following command to view the external IP address of the www-rule forwarding rule used by the load balancer:
gcloud compute forwarding-rules describe www-rule --region us-central1
- Use curl command to access the external IP address, replacing IP_ADDRESS with an external IP address from the previous command:
while true; do curl -m1 IP_ADDRESS; done
Create an HTTP load balancer
- First, 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" \ 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. 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 (130.211.0.0/22and35.191.0.0/16). This lab uses the target tagallow-health-checkto identify the VMs.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
- 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
Note the IPv4 address that was reserved:
gcloud compute addresses describe lb-ipv4-1 \ --format="get(address)" \ --global
- Create a health check 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 \ --global
- 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 \ --global
- 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 \ --address=lb-ipv4-1\ --global \ --target-http-proxy=http-lb-proxy \ --ports=80
Tag:Google Cloud
