Infrastructure as Code with CloudFormation

Clicking through the console to create resources is slow, error-prone, and impossible to reproduce reliably.

Infrastructure as Code (IaC) defines your infrastructure in files you can version, review, and deploy repeatedly.

AWS CloudFormation provisions AWS resources from a declarative template. You describe the desired end state and CloudFormation figures out how to create it.

Key terms:

• A template is a YAML or JSON file describing resources
• A stack is a deployed instance of a template
• Updating the template updates the stack

This template creates a single S3 bucket.

Parameters make templates reusable by accepting input at deploy time, like an environment name or instance size.

Outputs export useful values from a stack, such as a bucket name or endpoint URL, so other stacks or operators can reference them.

Create or update a stack from the CLI.

A change set previews exactly what an update will add, modify, or delete before you apply it — a safety net against accidental data loss.

If a stack update fails partway, CloudFormation rolls back to the last known good state, so you are never left with half-broken infrastructure.

Drift detection tells you when someone changed a resource manually outside CloudFormation, so you can bring reality back in line with the template.

In a pipeline, CodePipeline can deploy CloudFormation stacks automatically on every commit, making infrastructure changes follow the same review-and-deploy flow as your application code.

Test your IaC knowledge.

You learned Infrastructure as Code:

• Templates declare resources; stacks deploy them
• Parameters and outputs make templates reusable
• Change sets preview updates safely
• Drift detection and rollback keep infrastructure consistent

IaC makes your infrastructure repeatable, reviewable, and version-controlled.