Introduction This guide walks you through migrating an existing Tomcat application to AWS ECS Fargate — covering everything from session management and DB migration to Auto Scaling, with a production-ready setup in mind. Who this is for Developers migrating a Tomcat app to AWS Engineers new to ECS Fargate Final Architecture Internet │ ALB (port 80/443) │ ECS Fargate ├─ ElastiCache (Redis) ← session store └─ RDS (PostgreSQL) ← persistent data Enter fullscreen mode Exit fullscreen mode STEP 1: Create Security Groups Create dedicated security groups for ALB, ECS, Redis, and RDS. Following the principle of least privilege, only allow what is strictly necessary.…