====== Elastic Load Balancing (ELB) ======

**What it is:** A service that distributes incoming traffic across multiple targets (instances, IPs, containers).

**What it’s for:**
  * High availability and better performance.
  * Health checks and automatic routing away from unhealthy targets.

**Key ideas:**
  * Main types:
    * [[aws:network:elb:alb|ALB]] (Layer 7 HTTP/HTTPS)
    * [[aws:network:elb:nlb|NLB]] (Layer 4 TCP/UDP)
  * Integrates with ASG for scaling.

**Exam cues:**
  * “distribute traffic to multiple EC2 instances” → ELB.
  * “route based on URL path / host header” → ALB.

**Hard words:**
  * *distribute* /dɪˈstrɪbjuːt/: phân phối
  * *target* /ˈtɑːrɡɪt/: đích nhận traffic
  * *health check* /helθ tʃek/: kiểm tra sống