CloudFormation Features: Part I

Nested stacks

Nested stacks are created as part of other stacks. We use the AWS::CloudFormation::Stack resource to create a nested stack.

As our infrastructure grows, it can become more and more difficult to maintain it in a single file. With the growing infrastructure, we’ll also find some repeated patterns. We can isolate these common components and create dedicated templates for them. These dedicated templates can then be used by other stacks to create resources.

For example, security groups are a resource that multiple resources, like RDS and EC2, will use. If our organization has a common configuration of security groups to use, then instead of using the same resource configuration in multiple files, we can create a dedicated security group template and use it to create a security group within other stacks.

Note: To update a nested stack, update the parent stack.