CloudFormation Drift and ChangeSets

Drift in CloudFormation

CloudFormation can be used to create all kinds of AWS infrastructure. But what happens if we change the infrastructure created by CloudFormation manually (via the AWS Management Console or CLI)?

The new infrastructure won’t be in line with the CloudFormation template. This change is called drift. The term drift in IaC means the actual infrastructure configuration doesn’t match the configuration defined by the code. This is usually because of unwanted manual changes to the infrastructure. For example, we create a t2.micro EC2 instance using CloudFormation, but we use CLI or the AWS Management Console to change the instance type to t2.small.

So, how do we detect drift in AWS? CloudFormation has a feature to detect drift in infrastructure.