Architecture

Question 1

explain how prometheus gathers info from the app

Answer 1

Prometheus server make a request to the app (scrape) to /metrics endpoint and gets in response Sample Data

Question 1

what is PromQL?

Answer 1

language to query time series in Prometheus, for example avg(satori_query_failure_total{site=”olxua”})

Question 2

What is Service Discovery?

Answer 2

Prometheus can find our services by itself, no configuration needed

Question 3

What is Push Gateway?

Answer 3

used for short running jobs, for example cron-jobs: they can push metrics to PushGateway and later Prometheus can scrape it as it would the normal http service

Question 4

What is Alert Manager?

Answer 4

Prometheus can send alerts to Alerts Manager which will send a human understandable notification on email, pagerDuty, slack etc.

Question 5

explain prometheus architecture in general

Answer 5

short-lived jobs push metrics to PushGateway -> Prometheus pull metrics from PushGateway and from jobs (my apps and services) and 3rd party exporters (e.q. sql), prometheus finds my apps and services via Service Discovery, Prometheus sends alerts to AlertManager which push notification to slack; Grafana, API clients and Prometheus web UI collect Prometheus metrics using PromQL language