Building Load Balancers with Terraform for Scalable, Reliable Infrastructure

The servers are drowning in traffic. You need a gatekeeper that decides who goes where, instantly, without breaking. That gatekeeper is a load balancer. And in Terraform, you can build it fast, reproducible, and fault-tolerant.

A load balancer in Terraform is not just a resource. It’s a blueprint. You declare it once, commit it to version control, and it becomes part of your infrastructure state. No manual consoles. No click errors. Exact infrastructure, every time.

Terraform supports multiple load balancer types: AWS Application Load Balancer (ALB), Network Load Balancer (NLB), and Classic Load Balancer; Azure Load Balancer; Google Cloud HTTP(S) Load Balancer and TCP/SSL Proxy. The same workflow applies. Define resource blocks with provider-specific arguments. Plan. Apply. Done.

For AWS, an ALB in Terraform might look like this:

resource "aws_lb" "app" {
 name = "app-lb"
 internal = false
 load_balancer_type = "application"
 security_groups = [aws_security_group.lb.id]
 subnets = aws_subnet.public.*.id
}

resource "aws_lb_target_group" "app_tg" {
 name = "app-tg"
 port = 80
 protocol = "HTTP"
 vpc_id = aws_vpc.main.id
}

resource "aws_lb_listener" "front_end" {
 load_balancer_arn = aws_lb.app.arn
 port = 80
 protocol = "HTTP"

 default_action {
 type = "forward"
 target_group_arn = aws_lb_target_group.app_tg.arn
 }
}

This structure is simple to read and change. Variables can define ports, names, and scaling parameters. Modules let you reuse this load balancer code across projects, keeping every environment aligned while still allowing overrides.

Terraform state ensures the load balancer stays in sync with config files. If traffic grows, update instance counts or listener rules. Terraform compares the desired state to the current state, then applies only the changes needed.

Integrating a load balancer in Terraform gives you high availability. It distributes traffic evenly, isolates failures, and supports health checks tied to service instances. You can attach auto scaling groups or container services behind it, then reroute traffic in seconds.

Security is built in. Use security groups or firewalls to lock down access to certain CIDRs. Route traffic through HTTPS listeners with TLS certificates managed by AWS Certificate Manager, or the equivalent in Azure and GCP.

When combined with Infrastructure as Code, the load balancer becomes part of deployment pipelines. You can run terraform apply after each merge to main. That makes production updates consistent, traceable, and reversible.

Stop letting traffic bottlenecks wreck service quality. Build your load balancer in Terraform, commit it, and deploy it the same way every time. Check out hoop.dev to see it live in minutes.