Prometheus basics

Topic: Monitoring basics

Prometheus scrapes metrics from targets on an interval. Store time series; query with PromQL. Use for metrics and alerting in many environments.

Intent: How-to

Quick answer

  • Install Prometheus. Add scrape configs for targets. Metrics exposed on HTTP. Scrape interval per job.
  • Query with PromQL. Rate, sum, by. Use in Grafana or Alertmanager. Recording rules for heavy queries.
  • Retention and storage. Alertmanager for routing. High availability with federation or Thanos.

Prerequisites

Steps

  1. Install and scrape

    Install Prometheus. Configure scrape_configs. Targets expose /metrics. Verify in UI.

  2. Query and alert

    PromQL in UI or Grafana. Define alert rules. Configure Alertmanager.

  3. Retention and HA

    Set retention. Use recording rules. Consider Thanos or federation for HA.

Summary

Install Prometheus. Scrape targets. Query with PromQL. Alert and retain.

Prerequisites

Steps

Step 1: Install and scrape

Install. Configure scrape. Verify.

Step 2: Query and alert

PromQL. Alert rules. Alertmanager.

Step 3: Retention and HA

Retention. Recording rules. HA if needed.

Verification

  • Targets scraped. Queries return data. Alerts configured.

Troubleshooting

No scrape — Check target URL and network. High cardinality — Limit labels.

Next steps

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