What is CloudFormation?

AWS CloudFormation is a service that helps you automate the setup and management of your AWS resources (like EC2 instances, S3 buckets, RDS databases, etc.) in a consistent and repeatable manner. Think of it as a blueprint or recipe that tells AWS how to create and configure the things you need in the cloud.

You start by writing a template in either JSON or YAML format. This template is like a detailed instruction manual that describes all the AWS resources you want to create and how they should be configured.

Once your template is ready, you upload it to AWS CloudFormation. CloudFormation then reads your template and creates a "Stack" based on it. A Stack is essentially a collection of AWS resources that are created and managed as a single unit.

CloudFormation automatically provisions (sets up) all the resources defined in the template. It takes care of the order, dependencies, and relationships between the resources.

If you need to change or update your resources, you can modify the template and apply the changes. CloudFormation will update the Stack accordingly, without you needing to manually adjust the resources.

If something goes wrong during the creation or update process, CloudFormation can automatically rollback to the previous state, ensuring that your environment remains stable.