A Beginner’s Guide to AWS Load Balancer: What, Why & How

When your website or application starts getting more traffic, it’s important to make sure it doesn’t slow down — or worse, crash. That’s where Load Balancers come in.

If you're using AWS, the Elastic Load Balancer (ELB) makes it super easy to distribute incoming traffic across multiple targets like EC2 instances, containers, and IPs.

Let’s break it down.

🚀 What is a Load Balancer?

A Load Balancer is like a traffic manager for your app. It receives incoming requests and distributes them across multiple servers so that no single server is overwhelmed.

This improves:

• Performance
• Scalability
• High Availability

☁️ What is AWS Elastic Load Balancing (ELB)?

AWS ELB automatically distributes incoming application traffic across multiple targets in one or more Availability Zones. It also performs health checks and only sends traffic to healthy targets.

🔍 Types of AWS Load Balancers

1) Application Load Balancer (ALB)

• Best for HTTP/HTTPS traffic.
• Supports routing based on path, hostname, or query string.
• Great for microservices and container-based apps (like ECS/EKS).

2) Network Load Balancer (NLB)

• Best for TCP, UDP, TLS traffic.
• Handles millions of requests per second with ultra-low latency.
• Ideal for high-performance applications like real-time gaming or IoT.

3) Gateway Load Balancer (GLB)

• Designed for deploying third-party virtual appliances (like firewalls).
• Automatically scales and ensures high availability for those appliances.

✅ When Should You Use AWS Load Balancer?

• Your app runs on multiple EC2 instances.
• You want zero downtime deployments.
• You need to scale traffic based on demand.
• You want to route traffic based on specific rules (e.g., /api goes to a different service).

🔧 How to Load Balance Your Website Using AWS

1. Launch EC2 Instances: Host your application on multiple EC2 instances across different availability zones.
2. Create a Target Group: This is where your EC2 instances live.
3. Create a Load Balancer: Choose ALB or NLB depending on your traffic type.
4. Attach the Target Group: The load balancer now knows where to send traffic.
5. Update DNS: Point your domain to the Load Balancer’s DNS name (provided by AWS).

That’s it — your traffic is now balanced! 🎉

🧠 Final Thoughts

Using a Load Balancer is essential once your application starts growing. AWS makes it beginner-friendly with Elastic Load Balancing, giving you options based on your needs — whether it's a web app, an API, or a custom network protocol.

Start small, experiment in your free tier, and explore how it improves reliability and performance.

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