This document introduces Prometheus, an open-source monitoring system that allows instrumentation of everything including RPCs, interfaces, business logic, and logs. It provides client libraries that make instrumentation easy across many languages. The Prometheus server can handle over a million time series in one instance with no dependencies. It offers dashboards, expression queries, alerts and integrates with many systems. Time series have structured labels allowing flexible aggregation and complex math for rules and alerts. Prometheus costs less than $.001 per time series per month and is developed by SoundCloud, Boxever and Docker with an active community.