Amazon CloudWatch is monitoring and management service for applications and IT infrastructure. Natively integrated with 70+ AWS services, this monitoring service helps you obtain system-wide visibility into resource utilization, application performance, and operational health for your AWS Cloud infrastructure.
It can collect and track metrics in real time, and can send off notifications or automatically make changes via pre-defined triggers with CloudWatch alarms.
You can access the service and the operational reports using the AWS Console, CLI, API, or SDKs.
It employs a pay-as-you-go model, so you only pay for what you use, with no up-front commitment or minimum fee.