Today, we are announcing the availability of Amazon CloudWatch metrics for usage monitoring on AWS Config. AWS Config tracks changes made to supported resources and records them as configuration items (CIs), which are then delivered to an Amazon Simple Storage Service (Amazon S3) bucket. Amazon CloudWatch metrics is a monitoring service which provides data about the usage of your systems, including the ability to search, graph, and build alarms on metrics about AWS resources. With this release, you can now use Amazon CloudWatch metrics to verify your setup and understand your usage of AWS Config.
Source:: Amazon AWS