Okay, so I’ve been diving deep into AWS these days and today I wanted to talk about something that confused me A LOT in the beginning - Load Balancers. There are four types of Load Balancers in AWS, and at first, they all looked the same to me. But once I understood their layers and use cases, it all started to make sense.
This blog is my attempt to explain all four AWS Load Balancers in the easiest way possible - with visuals, analogies, and beginner-friendly terms. If you're also exploring cloud and DevOps like me, this will help you get a grip.
1.Classic Load Balancer (CLB) -- The Oldie But Goldie
This one’s been around for a while. It’s like that old Nokia phone - reliable, simple, but not really built for today’s advanced apps.
Features:
Supports both Layer 4 (TCP) and Layer 7 (HTTP/HTTPS)
Routes requests to EC2 instances
Lacks support for advanced routing (like path-based or host-based routing)
No container support or modern monitoring tools
#When to Use?
Only when you have some legacy systems running, or migrating old workloads. For anything modern, you’ll probably want to use ALB or NLB.
My thoughts: It still works, but not my go-to choice anymore.
2.Application Load Balancer (ALB) -- The Smart One 🧠
This is the modern HTTP/HTTPS load balancer. It's clever, context-aware, and knows how to handle different types of web traffic. Works on Layer 7 of the OSI model.
Features:
Smart routing: Supports path-based and host-based routing
Works great with containers and microservices (like ECS, Fargate)
Supports WebSockets and HTTP/2
Advanced monitoring with CloudWatch metrics
Integrated with AWS WAF for security
When to Use?
Whenever you want flexibility in routing traffic. Perfect for apps with multiple services like /login, /dashboard, /cart, etc.
My thoughts: Super helpful in modern architectures. I use this whenever I need custom rules or work with containers.
3.Network Load Balancer (NLB) -- The Speed Demon ⚡
This one’s all about speed and performance. NLB operates on Layer 4 (Transport Layer) and is designed to handle millions of requests per second with ultra-low latency.
Features:
Extremely fast and highly scalable
Supports TCP, UDP, and TLS traffic
Can handle volatile traffic spikes
You can assign Elastic IPs
Preserves the source IP for backend services
When to Use?
Real-time apps like financial systems, multiplayer games, or IoT workloads that need fast, reliable connections.
My thoughts: If speed is your top priority, this is your guy. But it’s not smart like ALB — it just forwards traffic.
4.Gateway Load Balancer (GWLB) -- The Security Guy 🔐
This one’s different. It’s not for routing user requests to your app - it's for routing traffic through security appliances like firewalls, intrusion prevention systems, etc.
Works on Layer 3 (Network Layer).
Features:
Integrates with third-party security appliances
Simplifies insertion of security services
Used in inline inspection of traffic
Deploy once, scale across multiple VPCs
When to Use?
When you want to add deep security inspection into your network flow. Great for enterprise-level setups.
My thoughts: Not for everyone, but if you're building something large-scale or security-heavy, it's a must-have.
Wrapping Up
That’s my take on AWS Load Balancers! I tried to keep it as simple and as "me" as possible.
If you're just starting in AWS, don't worry if this feels like too much. Save this, come back to it when you actually use them - trust me, it all starts to make sense once you do it hands-on.
If you liked this breakdown or learned something new, drop a like or comment. I'm learning and sharing as I go - let's connect and grow together!!!!
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