Your team needs to create CloudFormation stacks for multiple web applications. There are some common AWS resources that are used by most applications such as security groups. These resources are not frequently modified after being created. You want to manage these common AWS resources separately and other application stacks can easily reuse them when needed. How would you achieve this requirement?

Answer options:

A.Use a CloudFormation stack to create these resources and export the output values. Other CloudFormation stacks can import the resources through the Fn::ImportValue function.
B.Use a CloudFormation stack to include these commonly used resources and export the output values. Other CloudFormation stacks can import the resources through the Fn::GetAttr function.
C.Launch a CloudFormation stack to include the common resources and the stack is nested within other application CloudFormation stacks using the AWS::CloudFormation::Stack resource.
D.Use a CloudFormation stack to manage the common resources. In the AWS Console, choose “Import resources into stack” for other CloudFormation stacks to reuse its AWS resources.

Correct Answer – A
Option A is CORRECT because after a stack exports its output values, other stacks can import them through the Fn::ImportValue function. This method is useful when certain AWS resources in a stack are frequently used by other stacks.
Option B is incorrect because Fn::GetAttr is not the correct function to import the exported values from other stacks. Fn::ImportValue should be used.
Option C is incorrect because nested stacks are suitable when you want to use a single stack to manage all the resources. In this question, the information is shared between different stacks so the stack should export its values for others to use.
Option D is incorrect because “Import resources into stack” is used for moving resources between CloudFormation stacks. It is not suitable to be used here.
Reference:
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-stack-exports.html,
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-stack-imports.html