To understand and work with AWS-generated and custom metrics, it is important to understand a few basic concepts and terminologies used with Amazon CloudWatch.
CloudWatch namespaces are containers in which metrics for different applications are stored. It is a mechanism to isolate metrics of different applications from each other. Namespaces ensure that an application's metrics, as well as respective statistical data, are not accidentally mixed up with any other application's metrics. All the AWS services that use CloudWatch to register their metrics use a unique namespace. A namespace name begins with AWS/ and is generally followed by the application name. If you create a custom application and need to store metrics in CloudWatch, you must specify a unique namespace as a container to store custom metrics. Namespace can be defined at the time of creating the metrics. The namespace name can be a string of up to 256 characters including (A-Z, a-z, 0-9...