Module 2: Infrastructure as Code

CloudFormation Templates vs. Scripting – Explained

CloudFormation Templates:

AWS CloudFormation is a service that allows you to define and provision AWS infrastructure using code, written in either JSON or YAML format. CloudFormation templates are declarative in nature, meaning you describe what resources you want (like EC2 instances, S3 buckets, IAM roles), and AWS handles how to create them in the correct order.

These templates are reusable, version-controlled, and make it easy to create consistent infrastructure across multiple environments (e.g., dev, test, and production). They’re especially useful for large-scale infrastructure automation and managing complex dependencies between services.

Scripting:

Scripting (usually done using Shell, Python, or PowerShell) is an imperative approach to automating cloud infrastructure. With scripts, you write a series of commands that execute step by step, controlling how the infrastructure should be provisioned or managed. Scripts can use AWS CLI or SDKs to interact with AWS services and are very flexible.

Scripting is good for quick tasks or custom automation that doesn’t require managing a lot of interdependent AWS resources.

Key Differences and Similarities:

• Differences:

  • CloudFormation is declarative (you describe the end state), whereas scripts are imperative (you define step-by-step instructions).
  • CloudFormation is tightly integrated with AWS and manages resource dependencies automatically, while scripts require manual handling of these.
  • Templates are better for infrastructure provisioning; scripts are more flexible and suitable for tasks like backups, deployments, and batch operations.

• Similarities:

  • Both are forms of Infrastructure as Code (IaC).
  • Both aim to automate and streamline cloud operations.
  • Both can be version controlled and reused.

When to Use CloudFormation:

Use CloudFormation templates when you need to define and manage a full stack of AWS infrastructure, especially when deploying consistent environments repeatedly. It’s ideal for production environments where stability, repeatability, and automation are critical. For example, setting up a VPC with subnets, EC2 instances, IAM roles, and RDS in a single automated process.

When to Use Scripts:

Use scripting when you want to automate specific tasks or when you’re working in a more dynamic, less structured environment. For example, if you want to start and stop EC2 instances on a schedule, perform a backup, or quickly test configurations, scripting is faster and more straightforward.