Amazon ECS – Load Balancer Integrations

Application Load Balancer (ALB)

• Works with EC2 and Fargate launch types.

• Supports path-based and host-based routing.

• Ideal for containerized apps on dynamic ports (ECS integrates with ALB target groups to register tasks automatically).

Network Load Balancer (NLB)

• Best for ultra-low latency, high throughput workloads.

• Required for certain AWS PrivateLink integrations.

• Can handle millions of requests per second.

Classic Load Balancer (CLB)

• Legacy option, not recommended.

• No Fargate support and lacks modern routing features.

Key Architecture Pattern

• The load balancer is public-facing (port 80/443).

• Distributes traffic across ECS tasks running in one or more ECS Services.

• ECS automatically registers/deregisters tasks in target groups based on health checks.