Classic Load Balancer
- What it is
- The original AWS load balancer (2009), now previous generation. Also called ELB v1.
- Operates at both Layer 4 and Layer 7, but does neither as well as its replacements.
- Why it is deprecated in practice
- No content-based routing (no path or host rules).
- No dynamic port mapping — one container per host, so it does not suit ECS/EKS.
- Requires one load balancer per application instead of one with routing rules; more expensive at scale.
- No target groups, no Lambda targets, no gRPC/HTTP2, no WAF integration.
- Where it still appears
- Legacy EC2-Classic era workloads that have not migrated.
- AWS retired EC2-Classic in 2022; migrate CLBs to Application Load Balancer (ALB) or Network Load Balancer (NLB).
- Exam rule
- If a question offers Classic Load Balancer as an option for a new architecture, it is the wrong answer.
- See also
- load balancers for the family overview.