Prometheus

Prometheus is the open-source standard for systems monitoring and alerting (built on a high-performance multi-dimensional data model).

Prometheus delivers precise observability through a pull-based architecture and its powerful PromQL query language. It handles millions of time-series metrics by indexing data via key-value pairs (labels), allowing operators to slice performance data by service, instance, or data center. The ecosystem includes the Alertmanager for notification routing and the Node Exporter for hardware-level telemetry. Since joining the CNCF in 2016 as the second hosted project after Kubernetes, it has become the default stack for cloud-native infrastructure monitoring.

https://prometheus.io