Building and Optimizing an Enterprise AWS Architecture with ALB, IAM, and VPC

Introduction

Enterprise environments demand reliability, security, and scalability. This post covers how to build an enterprise-grade AWS architecture and optimize it to control costs.

Implementation Steps

1. Create a VPC with Subnets
   • Use public subnets for load balancers, private subnets for EC2 and databases.
   • Add NAT gateways for outbound internet access from private subnets.
2. Set up EC2 Instances in Auto Scaling Group (ASG)
   • Configure ASG with minimum and maximum instance counts.
   • Use launch templates with the right instance types.
3. Deploy Application Load Balancer (ALB)
   • Route traffic to healthy EC2 instances.
   • Use HTTPS with ACM certificates for SSL.
4. Implement IAM Roles and Policies
   • Apply least privilege principles for security.
5. Configure RDS Multi-AZ or Aurora for High Availability

Cost Optimization Tips

• Monitor NAT Gateway Usage: NAT gateways are charged hourly + data processed. Use VPC endpoints to reduce data going through NAT.
• Use Savings Plans or Reserved Instances: Commit to steady usage to reduce EC2 and RDS costs.
• Tune Auto Scaling Policies: Avoid over-provisioning by scaling based on CPU, memory, or request count.
• Use CloudWatch Metrics and Alarms: Detect idle resources and scale down when possible.
• Consider Aurora Serverless: Pay only for what you use on the database layer.