Multi-AZ three-tier web app

Public web tier, private app tier, managed database — highly available.

Requirements

Edge / DNS

Route 53 alias to ALB Single Elastic IP on one EC2 S3 static website only

Load balancing

Application Load Balancer (multi-AZ) NLB in one AZ only No load balancer — clients hit instances

Compute

Auto Scaling groups across AZs One large EC2 in a public subnet Lambda only (no containers/VMs needed)

Database

RDS Multi-AZ in private subnets RDS in a public subnet with open SG MySQL on a single EC2