Prometheus bootstrap internals

Prometheus is a system and service monitoring system. It collects metrics from configured targets at given intervals, evaluates rule expressions, displays the results, and can trigger alerts if some condition is observed to be true.

This series of articles try to dig deeply into Prometheus internals to help readers understand Prometheus well. The dig is based on Prometheus v2.18.1.

Tip: For more information about Prometheus, please visit here.

Actors

Prometheus starts up from cmd/prometheus/main.go. Inside main function, It prepares a group of actors (functions) and runs them concurrently. Actors include:

• Actor that handles application termination.
• Actor that manages scrape discovery.
• Actor that manages notification discovery.
• Actor that manages scrape.
• Actor that handles reloading configuration.
• Actor that handles initial configuration loading. After loading, It executes a list of ApplyConfig functions to initialize other actors. reloadReady channel will also be closed to notify other actors to proceed.
• Actor that manages rules.
• Actor that handles TSDB.
• Actor that handles web requests.
• Actor that sends notifications.