Application Load Balancer (ALB)

Overview

The Application Load Balancer operates at the request level (layer 7), routing traffic to targets (EC2 instances, containers, and IP addresses) based on the request’s content. You can load balance HTTP/HTTPS applications and use layer 7-specific features such as X-Forwarded-For headers.

It supports HTTPS termination between the clients and the load balancer. It also supports the management of SSL certificates through AWS IAM and AWS Certificate Manager for predefined security policies.

Server Name Indication (SNI) supports multiple secure websites using a single secure listener. With Server Name Indication, a client indicates the hostname to connect to.

IP addresses as targets allow for load balancing any application hosted in AWS or on-premises using IP addresses of the application backends as targets.

The image below provides an overview of the ALB.