Create a Load Balancer

A Load Balancer spreads incoming traffic across several servers so no one server carries everything and the loss of one does not take you down. You build it in layers: the load balancer itself, a listener, a pool of servers, and a health check.

Step 1 — Create the load balancer

1. Open Networking, then Load Balancers, and click Create Load Balancer.
2. Set:
   • Name: for example web-lb.
   • Subnet: the subnet your backend servers are on.
   • Availability Zone: match your servers' region.

Step 2 — Add a listener

The listener is what the load balancer listens for.

• Protocol and Port: for a website, HTTP on 80, or HTTPS on 443. For HTTPS, attach a certificate (see TLS Certificates).

Step 3 — Create a pool

The pool is the group of backend servers and how traffic is shared.

• Algorithm: Round Robin sends requests to each server in turn and suits most cases.

Step 4 — Add members

The members are the actual servers.

• Add each backend server and the port its application listens on (for example 80).

Step 5 — Add a health monitor

The health check quietly removes an unhealthy server from rotation until it recovers.

• Choose a type (an HTTP check on a health URL, or a simple TCP check) and the interval.

Finish

Give the load balancer a public IP and open the listener's port in your security rules. For real redundancy, put the backend servers in an anti-affinity Placement Group so they never share a host.