Observability · Flashcard
Prometheus starts with no exporters. What can you query already?
- AIts own prometheus_* metrics — the server scrapes itself
- BNothing at all — the TSDB stays empty until a target is added
- CHost metrics — the server collects CPU and memory by itself
- DOnly up — the one series the server maintains without targets
Why this is the answer
A default Prometheus scrapes its own /metrics endpoint, so prometheus_tsdb_*, prometheus_http_* and the rest are queryable immediately — which is how you check that the server is healthy before anything else exists. The TSDB is therefore not empty, host metrics need node_exporter as a separate process, and up is one of many series rather than the only one.
Official docs