Metrics

Just as distributed traces do, metrics provide information about the state of a running system to developers and operators. The data collected via metrics can be aggregated over time to identify trends and patterns in applications graphed through various tools and visualizations. The term metrics has a broad range of applications as they can capture low-level system metrics such as CPU cycles, or higher-level details such as the number of blue sweaters sold today. These examples would be helpful to different groups in an organization.

Additionally, metrics are critical to monitoring the health of an application and deciding when an on-call engineer should be alerted. They form the basis of service level indicators (SLIs) (https://en.wikipedia.org/wiki/Service_level_indicator) that measure the performance of an application. These indicators are then used to set service level objectives (SLOs) (https://en.wikipedia.org/wiki/Service-level_objective) that organizations use to...