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Create AWS VPC Using Terraform | Easy Step-By-Step Guide

07 Oct 2024

This hands-on lab will walk you through how to set up a Virtual Private Cloud (VPC) on AWS using Terraform.

A Virtual Private Cloud is a foundational component for building your cloud infrastructure on AWS. VPCs provide network isolation, security, and control over your cloud resources. By the end of this tutorial, you’ll be able to create a secure and scalable VPC with public and private subnets, an Internet Gateway, and a NAT Gateway.

What is an AWS VPC?

Amazon Virtual Private Cloud (VPC) enables you to launch AWS resources in a logically isolated virtual network that you define. You have complete control over your virtual networking environment, including selection of your own IP address range, creation of subnets, and configuration of route tables and network gateways.

A well-designed VPC architecture is essential for:

Network isolation and security
Controlling inbound and outbound traffic
Segmenting resources based on function and security requirements
Enabling communication between AWS resources
Providing internet access where needed while keeping sensitive resources private

VPC Components Overview

A properly configured VPC consists of several key components that work together to provide a secure and functional network infrastructure:

Subnets: Subdivisions of your VPC’s IP address range where you can place groups of resources. Subnets can be public (accessible from the internet) or private (isolated from direct internet access).

Internet Gateway: Enables communication between resources in your VPC and the internet. Required for any resources that need to be publicly accessible.

NAT Gateway: Allows resources in private subnets to access the internet for updates and patches while preventing inbound internet connections. This maintains security while enabling necessary outbound connectivity.

Route Tables: Control how network traffic is directed within your VPC and to external networks.

Public vs. Private Infrastructure

A production-grade VPC typically separates resources into public and private subnets based on their accessibility requirements:

Public Infrastructure: Resources that need to be accessible from the internet, such as load balancers, bastion hosts, or web servers. These resources reside in public subnets with routes to an Internet Gateway.

Private Infrastructure: Backend resources like databases, application servers, and internal services that should not be directly accessible from the internet. These resources reside in private subnets and use NAT Gateways for outbound connectivity.

This separation implements defense-in-depth security principles by limiting the attack surface and protecting sensitive resources from direct internet exposure.

Security Best Practices

When designing your VPC architecture, consider these security best practices:

Use private subnets for all resources that don’t require direct internet access
Implement network access control lists (NACLs) for subnet-level traffic filtering
Use security groups for instance-level firewall rules
Enable VPC Flow Logs for network traffic monitoring and security analysis
Design with high availability by using multiple Availability Zones
Apply the principle of least privilege to all network configurations

Infrastructure as Code with Terraform

Using Terraform to provision your VPC infrastructure provides several advantages:

Repeatability and consistency across environments
Version control for infrastructure changes
Easy replication for development, staging, and production environments
Automated deployment and teardown
Clear documentation of infrastructure design through code