CloudFormation cannot delete an S3 bucket that contains objects. When the developers attempt to delete temporary stacks, the delete operation fails if the associated S3 bucket still has objects. Because the bucket name is derived from the stack name, failed deletions can also prevent re-creation of stacks with the same names until the bucket is manually emptied and deleted. This causes friction for development and continuous integration workflows.
To resolve this, the solution must ensure that, during stack deletion, all objects are removed from the S3 bucket so that CloudFormation can delete the bucket successfully. CloudFormation does not natively support automatic deletion of bucket contents. However, CloudFormation custom resources can be used to perform custom actions during stack lifecycle events.
Option A proposes associating a Lambda function with a CloudFormation custom resource. The custom resource can be invoked during stack deletion to list and delete all objects (and object versions if versioning is enabled) in the specified bucket. Once the bucket is emptied by the Lambda function, the standard CloudFormation deletion process can successfully delete the bucket resource.
In addition to emptying the bucket, the IAM role used by CloudFormation must have permissions to delete objects in the bucket. If CloudFormation uses an execution role that lacks s3:DeleteObject (and potentially s3:ListBucket) permissions, the bucket-cleanup Lambda function or CloudFormation itself would not be able to remove objects. Option D ensures that CloudFormation operations are invoked by a role that has s3:DeleteObject permissions on bucket objects, enabling the custom resource to perform the deletions.
Option B is incorrect because, although DeletionPolicy can be set to Delete, there is no such capability as CAPABILITY_DELETE_NONEMPTY in CloudFormation, and DeletionPolicy alone does not override the S3 service requirement that buckets must be empty before deletion.
Option C’s Retain DeletionPolicy leaves the bucket behind when the stack is deleted. While an external AWS Config rule could clean up stale buckets, it complicates the design and does not directly solve the problem of re-creating stacks with the same bucket name in a predictable, immediate way.
Option E configures a bucket policy to grant s3:DeleteObject permissions, but this is not sufficient alone. CloudFormation still must assume a role with the appropriate permissions. Bucket policy and IAM role permissions must both be considered, but the key action to resolve the deletion failure is to explicitly empty the bucket through a custom resource, as in option A, and ensure the execution role has delete permissions, as in option D.
Therefore, implementing a Lambda-backed custom resource to empty the S3 bucket during stack deletion (option A) and ensuring the CloudFormation execution role has s3:DeleteObject permissions (option D) resolves the deletion errors and allows developers to delete and recreate stacks freely.
[References:AWS documentation on CloudFormation behavior with S3 bucket deletion and the requirement that buckets must be empty before deletion.AWS documentation on CloudFormation custom resources and Lambda-backed custom resources for performing custom actions during stack operations.]
