Prometheus Monitoring Software For OpenMetrics And Kubernetes
Prometheus scrapes endpoints, stores metrics in time-series database & can run on various platforms incl Windows, Linux, Kubernetes. It's part of CNCF ecosystem & has automatic service discovery for K8s workloads.
Prometheus itself is monitoring software. It runs as a long-running service that scrapes endpoints (which you configure as scrape targets) and stores the metrics in a time-series database. Those endpoints are expected to provide metrics in the format you have mentioned, which has become known as the 'OpenMetrics' format. The OpenMetrics format started as just a Prometheus thing, but it's become popular enough that many other monitoring tools will happily also scrape or 'understand' OpenMetrics formatted metrics. Prometheus can run on pretty much anything because it's a Go program it just run...