AWS Certified SysOps Administrator Practice Exam

What issue might cause an S3 bucket deletion to fail when it appears empty?

1. There are IAM policies preventing deletion

2. The S3 bucket is being replicated in another region

3. Versioning is enabled and delete markers exist

4. All files have been archived to Glacier

The correct answer is: Versioning is enabled and delete markers exist

When considering the deletion of an S3 bucket, it's important to understand how versioning affects the contents of the bucket. When versioning is enabled on an S3 bucket, every object has its own unique version, including delete markers which indicate that an object was deleted. Even if a bucket appears empty in terms of visible objects, the existence of a delete marker means that the object is not truly gone; it's simply marked as deleted. Therefore, when you attempt to delete the bucket, if there are any objects associated with delete markers due to versioning, the deletion will fail. The bucket needs to be emptied completely, which includes removing all versions and delete markers before it can be successfully deleted. This mechanism ensures that objects are not permanently lost without explicit action, which can safeguard against accidental deletions. In contrast, while IAM policies could potentially restrict deletion actions and replication could impose limits under certain conditions, they do not directly relate to the visibility of the S3 bucket's contents. Archiving to Glacier does not prevent the deletion of the bucket, as only the metadata might be affected, not the bucket itself. Thus, versioning and the presence of delete markers present the most direct challenge when trying to delete a seemingly empty bucket.