Prometheus is a monitoring software that runs as a long-running service, scraping endpoints and storing metrics in a time-series database. It's known for its OpenMetrics format, which has become popular among many other monitoring tools. Prometheus can run on various platforms, including Windows, Linux, Kubernetes, and more. It's well-suited for running on Kubernetes, offering automatic service discovery to monitor K8s workloads.

Source: https://dev.to/ibrahimsi/prometheus-how-its-work-457j