Prometheus
Prometheus is an open-source systems monitoring and alerting toolkit that collects metrics from targets at specified intervals, stores them in a time-series database, and evaluates alert rules to trigger notifications.
Prometheus is a monitoring solution designed for cloud-native and containerized environments. It works by scraping metrics endpoints (HTTP interfaces) on monitored systems and applications, pulling structured data about CPU usage, memory, disk I/O, and application-specific performance indicators.
The collected metrics are stored in Prometheus's built-in time-series database with timestamps, allowing you to query historical data and visualize trends. You define alerting rules in configuration files; when conditions are met (e.g., CPU usage exceeds 90%), Prometheus sends alerts to external services like PagerDuty or Slack.
Example: A web server exports metrics via http://localhost:9090/metrics. Prometheus scrapes this endpoint every 15 seconds, stores the data, and can alert ops teams if response latency spikes above threshold.
Prometheus is commonly paired with Grafana for visualization dashboards and is a core component of modern observability stacks, especially in Kubernetes environments.