The cfn-init helper script reads template metadata from the AWS::CloudFormation::Init key and acts accordingly to: Fetch and parse metadata from CloudFormation. Install packages. Write files to disk. Enable/disable and start/stop services.

What is CloudFormation file?

A CloudFormation template is a JSON or YAML formatted text file. … txt . CloudFormation uses these templates as blueprints for building your AWS resources. For example, in a template, you can describe an Amazon EC2 instance, such as the instance type, the AMI ID, block device mappings, and its Amazon EC2 key pair name.

Why is CloudFormation used?

You can use CloudFormation to modify and update the resources in your existing stacks in a controlled and predictable way. By using templates to manage your stack changes, you have the ability to apply version control to your AWS infrastructure just as you do with the software running on it.