Rudimentary AWS Setup [with Terraform]

This repository contains a Terraform script to instantiate a minimally-functional AWS infrastructure as follows:

• VPC
  • Public Subnet
    • Bastion/NAT host
  • Private Subnet
    • Empty/Sample EC2 instance

1. Routing tables to facilitate communication between various constituents of the infrastructure and The Internet. Routing tables enabling intra-VPC traffic exist by default and require no explicit creation.

2. The public subnet is accessible form the WWW via an Internet Gateway, private one is not; because there's no route from it to the Internet Gateway.

3. All subnets can "dial-out" to WWW.

   • Public subnet through the Internet Gateway.
   • Private subnet through the Bastion/NAT, which in turn connects to the WWW through the Internet Gateway.

4. Bastion/NAT host has a public IP and is wrapped in a security group which accepts SSH (port 22) connections from The Intenet, any connection from the VPC (all subnets), and allows all traffic out.

5. Empty EC2 instance is wrapped in a security group accepting SSH connections from the public subnet, any connection from its own subnet, and allows all outbound traffic.

Non-standard CIDR 222.33.0.0/16 is chosen to limit confusion, as every VPC tutorial inexplicably uses 10.0.0.0/16. Ample comments are provided inline.

Network Diagram

The setup is concisely illustrated below. Outbound traffic is not shown for the sake of brevity.

Installation

• Create a key pair on AWS:
  • EC2 > Key Pairs > Create Key Pair
• Edit variables.tf: insert the name of the aforemade key pair.
• Install Terraform
• cd [ whatever folder has main.tf and variables.tf ]
• terraform plan
• terraform apply