Prometheus

Prometheus is an open-source systems monitoring and alerting toolkit originally built at SoundCloud and now a graduated Cloud Native Computing Foundation (CNCF) project. It collects and stores metrics as time-series data, identified by metric names and key-value label pairs, using a pull-based model. It ships with PromQL, a powerful query language for slicing and aggregating that data, along with a built-in Alertmanager for routing notifications.

Prometheus has become the de facto standard for metrics collection in cloud-native and Kubernetes environments, making it a near-universal requirement in SRE and DevOps roles. Companies operating microservices at scale rely on it for observability, capacity planning, and incident response. As AI/ML workloads move into production on Kubernetes, Prometheus is increasingly used to monitor GPU utilization, model-serving latency, and pipeline health.