Until now, we have seen how we can create and use different AWS services such as EC2, S3, SQS, and so on using their respective APIs. Consider that you want to create a stack of different resources like a few EC2 instances and then create EBS volumes and attach them to the instances, then create S3 buckets, then create a database, and so on. AWS provides a way to create such a set of resources by allowing users to write a template that specifies the resources to be created. This template can be written using the JSON or YAML format and is called a CloudFormation template, and the Amazon service that parses and executes this template is called as the AWS CloudFormation service.

Thus, CloudFormation is a service that helps users to model and set up their AWS resources and create their cloud environment without spending much time on managing these resources and allows them to focus on the applications that run in AWS. For example, if you want to launch two EC2 instances in a specific order, the CloudFormation template can easily be configured to implement this order. So, when the template is executed, the EC2 instance will be created in the order specified in the template.