Application Load Balancer (ALB)

Application Load Balancer (ALB) is part of AWS Elastic Load Balancing and operates at layer 7 (HTTP/HTTPS). It evaluates incoming requests and distributes them to appropriate targets such as EC2, Lambda, or IP addresses based on content-aware listener rules. ALB supports modern web application patterns like microservices, REST APIs, and serverless apps, offering flexibility and scalability with centralized traffic control.

This lesson examines how we define routing logic with ALB, which is crucial for building microservice-aware infrastructure. We’ll learn how listener rules work, how to configure them based on hostnames and paths, and how they directly support application modularity and CI/CD practices. These skills reflect real tasks covered in the DVA-C02 exam, particularly under the development and deployment domains: configuring scalable request routing, securing traffic paths, and applying architectural patterns using target groups and routing rules.

ALB listener rules

ALB uses listener rules to control how requests are routed. These rules define conditions such as host headers, path patterns, or query parameters that determine which target group a request should be sent to. ...