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Prometheus

by Prometheus Authors / Cloud Native Computing Foundation · Application

Pull-based metrics monitoring system and time-series database with the PromQL query language, service discovery and the Alertmanager component

Apache-2.0 licenseOpen sourceFreeSelf-hostedSelf-hostable
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Checked Nov 2, 2026

Overview

Prometheus is an open-source monitoring system and time-series database, a graduated project of the Cloud Native Computing Foundation licensed under Apache-2.0. It periodically scrapes HTTP endpoints that expose metrics in a simple text format, stores the samples in a local time-series store keyed by metric name and labels, and lets operators query and aggregate them with PromQL. Alerting rules written in PromQL feed the separate Alertmanager, which groups, silences and routes notifications.

Targets are found through static configuration or service discovery for Kubernetes, cloud providers, Consul and DNS. Hundreds of exporters translate existing systems (hosts via node_exporter, databases, web servers, hardware) into Prometheus metrics, and client libraries instrument applications directly. Grafana is the usual front end for dashboards.

Each server stores data locally and is designed to run independently; long-term or highly available storage is delegated to remote-write backends such as Mimir, Thanos or Cortex. Prometheus is not meant for logs, traces or high-cardinality event data, and retention on a single node is bounded by local disk.

Capabilities

  • Pull-based scraping of metrics endpoints with service discovery
  • Multi-dimensional data model with labels and PromQL querying
  • Local time-series storage with remote-write to long-term backends
  • Alerting rules and Alertmanager routing, grouping and silencing
  • Exporter ecosystem and client libraries for instrumenting code
  • Built-in expression browser and HTTP API

Typical workflows

  1. Monitor hosts in a cluster with node_exporter and alert on resource pressure
  2. Instrument a web service and track request latency percentiles
  3. Feed Grafana dashboards from one or more Prometheus servers

Strengths

  • Simple operational model with a single binary and local storage
  • CNCF graduated with a very large exporter ecosystem
  • Expressive query language for time series

Limitations

  • Single-node storage without clustering; HA and long retention need remote backends
  • Not suited for logs, traces or high-cardinality events
  • Pull model requires network reachability to targets or a push gateway

Prerequisites

  • Targets exposing metrics (exporters or instrumented apps)
  • Local disk for the time-series database

Who it is for

  • Operations and SRE teams
  • Developers instrumenting services
  • Kubernetes operators

Alternatives & comparison

Grafana is the visualization layer typically placed on top of Prometheus rather than a replacement. Uptime Kuma provides black-box availability checks without a metrics model. Columnar databases such as ClickHouse can store metrics at larger scale but lack Prometheus' scraping, discovery and alerting conventions.

  • ClickHouse

    Open-source columnar OLAP database server for fast aggregations over billions of rows, with MergeTree storage, SQL and a managed ClickHouse Cloud

    Open sourceOpen source
  • Grafana

    Dashboarding and alerting platform that visualizes metrics, logs and traces from Prometheus, SQL databases and dozens of other data sources

    MixedOpen source
  • Uptime Kuma

    Self-hosted uptime monitor with HTTP, TCP, DNS, ping and keyword checks, many notification channels and public status pages

    Open sourceOpen source
Compare Prometheus with its alternatives →

Sources & verification

Primary sources consulted for this record. Claims are tied to the fields each source supports; the automated link checker re-verifies every URL on a schedule.

Confidence
High
Reviewed
Nov 1, 2026
Links
Broken · Nov 2, 2026

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