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CloudFormation

Links: 102 AWS DVA Index

  • CloudFormation is a declarative way of outlining your AWS Infrastructure, for any resources (most of them are supported).
  • CloudFormation is free.
  • Cost
    • Each resources within the stack is tagged with an identifier so you can easily see how much a stack costs you.
    • You can estimate the costs of your resources using the CloudFormation template.
  • Separation of concern: create many stacks for many apps, and many layers.

How CloudFormation works

  • Templates have to be uploaded in S3 and then referenced in CloudFormation
CloudFormation references a template from Amazon S3, no matter what. If you upload the template from the AWS console, it gets uploaded to Amazon S3 behind the scenes, and CloudFormation references that template from there.
  • Template is the yml file.
  • To update a template, we can't edit previous ones we have to re upload a new version of the template to AWS.
    • CloudFormation will figure out the changes between the old and the new template and make the required changes to the infrastructure.
  • Stacks are identified by a name.
We can have multiple templates inside stack. For example templates referencing each other for better separation of concerns.
  • Deleting a stack deletes every single artifact that was created by CloudFormation.
  • If replacement is true then the resource will be terminated and a new one will be created.
Templates are just the instruction. To delete the resources you delete the stack.
Every resource, creation and updation has to happen via CloudFormation.

Last updated: 2022-05-18