Chapter 3: Validation, Linting, and Deployment of the Stack

1. From 9,000 and above.
2. Linting is the process of evaluating the template against linter rules and is performed by cfn-lint. Validation is performed by CloudFormation and checks whether the template is valid and can be processed by CloudFormation.
3. There are several steps:

   (a) CloudFormation will check whether the stack exists or not.

   (b) CloudFormation will create a ChangeSet for a new or existing stack.

   (c) CloudFormation will execute the ChangeSet and listen to the stack events.

   (d) If there is a failure, CloudFormation rolls back the changes and informs the user about the issue.

4. No, ChangeSets must have unique names, otherwise you will get a 400 AlreadyExists error.
5. The name of the rule file and the rule class must be the same.
6. Just add the necessary change to the template or parameters and run the stack update.