This lesson instructs the student on CloudFormation Drift Detection. CloudFormation Stack Drift occurs when the resources in a stack have drifted from their original creation template. This can become a major problem and Drift Detection can be used to identify this problem. After the problem is identified, the lesson covers the steps that can be taken to bring the CloudFormation stack back into synch with the original template. Stack updates can be used to bring the stack back in to synch and should be used in most cases to update the stack at any time.