You have deployed a set of web servers in VPC along with an Amazon S3 bucket using AWS CloudFormation. Critical Project documents are uploaded in the S3 bucket. A new version for a web application is released & this needs to apply to this Stack using the AWS CloudFormation template. You need to ensure all critical Documents in the existing S3 bucket are intact while AWS CloudFormation creates a replacement resource & delete old resources. Which of the following can be used to meet this requirement?

Answer options:

A.Use UpdateReplacePolicy as Snapshot with Resource Attribute in AWS CloudFormation.
B.Use DeletionPolicy as Snapshot with Resource Attribute in AWS CloudFormation.
C.Use DeletionPolicy as Retain with Resource Attribute in AWS CloudFormation.
D.Use UpdateReplacePolicy as Retain with Resource Attribute in AWS CloudFormation.

Correct Answer: D
 AWS CloudFormation template attributes can be used to retain or backup resources before deletion of stack. UpdateReplacePolicy Attribute is used to retain / backup resources during the stack update process. DeletionPolicy attribute is used to retain /backup of resource before stack is deleted. Stack is being updated in the above case,so to retain the old resource, the UpdateReplacePolicy attribute needs to be specified.
Option A is incorrect as the Amazon S3 bucket does not support snapshot & you need to use UpdateReplacePolicy with retain.
Option B & C is incorrect as DeletionPolicy Resource Attribute is used when a resource is being deleted & not when a Resource is updated.
For more information on using Resource Attributes for AWS CloudFormation, refer to the following URL-
https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-attribute-updatereplacepolicy.html