driftStatus 
  Status of the StackSet's actual configuration compared to its expected template and parameter configuration.
- DRIFTED: One or more of the stack instances belonging to the StackSet differs from the expected template and parameter configuration. A stack instance is considered to have drifted if one or more of the resources in the associated stack have drifted.
- NOT_CHECKED: CloudFormation hasn't checked the StackSet for drift.
- IN_SYNC: All the stack instances belonging to the StackSet match the expected template and parameter configuration.
- UNKNOWN: This value is reserved for future use.