5.3.1 VPC Basics – CIDR & Subnets

5.3.1 VPC Basics – CIDR & Subnets

In this step, you create the VPC and subnets that host the AI Production Management System.

For this workshop, we use a VPC similar to your real environment:

  • VPC name: vpc-ims
  • CIDR block: 12.0.0.0/16
  • Availability Zones: ap-southeast-1a and ap-southeast-1b
  • Subnets:
    • Public-Subnet1 in ap-southeast-1a – 12.0.1.0/24
    • Public-Subnet2 in ap-southeast-1b – 12.0.2.0/24
    • Private-Subnet1 in ap-southeast-1a – 12.0.3.0/24
    • Private-Subnet2 in ap-southeast-1a – 12.0.4.0/24
    • Private-Subnet-5 in ap-southeast-1b – 12.0.5.0/24

Why this matters

  • Public subnets expose only the entry point (ALB / NAT Gateway) to the Internet.
  • Private subnets keep application containers and database isolated from direct public access.
  • Using two AZs improves availability of the frontend entry point and backend services.

Diagram: IMS VPC layout

IMS VPC with public and private subnets across AZs

Workshop tasks

  • Recreate or verify a VPC with CIDR 12.0.0.0/16 and the subnets above.
  • Tag subnets clearly (e.g., ims-public-1a, ims-public-1b, ims-private-1a, ims-private-1a-extra, ims-private-1b).
  • Attach the private subnets later to the ECS cluster and RDS subnet group.