Lesson 15 / 26

Elastic Load Balancer at a Glance

Q: You need to route requests to different backend services based on the URL path. Which fits best?

Application Load Balancer. ALB understands HTTP and can route based on path, host, or headers.

Spreading traffic across instances so no single server is overwhelmed.

What an ELB does

An Elastic Load Balancer (ELB) sits in front of your EC2 instances and distributes incoming traffic across healthy ones, so no single instance is overloaded.

ALB, NLB in brief

Application Load Balancer (ALB) understands HTTP — routes by path/host, great for web apps. Network Load Balancer (NLB) works at the TCP layer — extremely fast, for raw throughput.

Pair it with Auto Scaling

An ELB alone doesn't add servers. Pair it with an Auto Scaling Group so the fleet grows and shrinks with demand, and the load balancer routes to whatever's currently healthy.

Quick check: You need to route requests to different backend services based on the URL path. Which fits best?

Network Load Balancer
Application Load Balancer
Security Group

Answer

Application Load Balancer — ALB understands HTTP and can route based on path, host, or headers.