CloudWatch Metrics, Namespaces, and Dimensions

Amazon CloudWatch is AWS's unified observability service that collects metrics, logs, and traces from your AWS resources and applications. It gives you a complete picture of your infrastructure health, enabling you to detect anomalies, set alarms, and automatically react to operational changes. CloudWatch is deeply integrated with almost every AWS service and is the primary monitoring tool tested in the SAA-C03 exam.

A CloudWatch metric is a time-ordered set of data points representing the value of a measurable aspect of a resource over time — for example, CPUUtilization for an EC2 instance measured every minute. Metrics are identified by their namespace, name, and dimensions. AWS publishes hundreds of built-in metrics automatically, and you can publish your own custom metrics from your application code or scripts.