Article · Wikipedia archive · Last revised May 28, 2026

Checkmk

Checkmk is a monitoring platform for hybrid IT environments and applications, developed in Python and C++. Originally released in 2009 as an extension to Nagios, it has since evolved into a standalone system that integrates infrastructure monitoring with application-level metrics. The software is developed by Checkmk GmbH, headquartered in Munich, Germany.

Last revised
May 28, 2026
Read time
≈ 5 min
Length
1,082 w
Citations
24
Source
Wikipedia ↗
Checkmk
DevelopersCheckmk GmbH (headquartered in Munich, Germany; previously tribe29 GmbH and Mathias Kettner GmbH)
Initial release2008 (2008)
Stable release
2.5.0 / April 28, 2026 (2026-04-28)
Written inPython, C++
Operating systemLinux
Available inEnglish (UI)
TypeIT infrastructure monitoring, Observability
LicenseGNU GPL v2 and other open-source licenses; Checkmk Enterprise License1
Websitecheckmk.com
Repository

Checkmk (pronounced /ˈtʃɛkˌɛmˈkeɪ/; CHECK-em-kay) is a monitoring platform for hybrid IT environments and applications, developed in Python and C++. Originally released in 2009 as an extension to Nagios, it has since evolved into a standalone system that integrates infrastructure monitoring with application-level metrics. The software is developed by Checkmk GmbH (formerly tribe29), headquartered in Munich, Germany.23 4 5

History

Checkmk was developed in 2008 by Mathias Kettner in Munich, Germany.2 It was developed as an extension for the Nagios monitoring system to provide alternative configuration and performance capabilities.67 The initial version, then styled as Check_MK, was released in April 2009 under the GNU General Public License (GPL).

In 2019, the developing company, Mathias Kettner GmbH, rebranded as tribe29 GmbH and changed the product name to Checkmk.8 In April 2023, the company was renamed Checkmk GmbH9. In February 2025, the company announced a strategic investment from the growth equity firm PSG Equity.1011 In April 2026, version 2.5 was released.12

Checkmk has been documented in academic research on monitoring large-scale IT systems in Germany13.

Editions

In March 2026, the software nomenclature was updated. Checkmk is distributed under an Open-core model in several editions:

  • Checkmk Community: An open-source edition (GPLv2) based on the Nagios core.
  • Checkmk Pro: A commercial edition that replaces the Nagios core with the Checkmk Micro Core (CMC). This edition introduces administrative tools such as the "Agent Bakery" for automated configuration management, as well as reporting modules for Service Level Agreements (SLA) and capacity planning. It includes native connectors for Kubernetes and public cloud APIs (AWS, Azure, GCP).
  • Checkmk Ultimate: A commercial edition building upon Checkmk Pro with additional features for dynamic infrastructure and Kubernetes. Technical additions include a push-based agent communication mode, a dedicated data backend for OpenTelemetry, and a relay unit for outbound-only monitoring of remote sites. A variant of this edition is available for managed services providers (MSPs), providing logical data separation and multi-tenant management capabilities.
  • Checkmk Cloud: A Software as a Service (SaaS) edition managed and hosted by Checkmk GmbH, offering the functional scope of Checkmk Ultimate through a subscription-based delivery model.14

Functionality

Checkmk provides monitoring for servers, networks, and applications. Its features include:

  • Alerting and notification: Systems for escalating alerts via email, SMS, messaging platforms, and ITSM tools. Checkmk Cloud features AI-powered troubleshooting, which uses generative AI to analyze alert data and provide natural language explanations of root causes.
  • Visualization: Dashboards and time-series graphing with support for exporting metrics to Grafana and Prometheus.
  • Business intelligence (BI): A module for mapping application dependencies and monitoring multi-component systems.
  • Synthetic monitoring: Integration with the Robot Framework and Playwright for automated user-experience testing.
  • Inventory and logs: Hardware and software asset tracking alongside event management via log analysis.
  • Reporting: Tools for capacity planning, availability reporting, and SLA analysis.

Architecture and technology

Checkmk employs a rule-based configuration system where parameters are defined through rules that are applied to hosts based on tags or group memberships.

Monitoring cores

  • Nagios core: The open-source edition (Checkmk Community) uses the Nagios core to execute monitoring checks.15
  • Checkmk Micro Core (CMC): Included in commercial editions (Checkmk Pro, Checkmk Ultimate and Checkmk Cloud), the CMC is a proprietary engine written in C++. It allows for configuration changes without restarting the core process.16

Data collection and transport

Checkmk identifies monitorable components on a host via a service discovery mechanism.1718

  • Pull and push models: The software primarily uses a "pull" model, where the monitoring server queries the agent. Checkmk Ultimate and Checkmk Cloud also support a "push" model, where agents initiate the connection to the server.19
  • Checkmk Relay: Introduced for Checkmk Ultimate and Cloud, this container enables the monitoring of remote or segmented networks without requiring inbound firewall rules.12
  • Agent and agentless collection: Collection occurs via agents for Linux and Windows, or through protocols such as SNMP and WMI.20
  • OpenTelemetry: Checkmk Cloud and Checkmk Ultimate feature a native backend for the ingestion of OpenTelemetry (OTLP) metrics, enabling the monitoring of application-level Rate, Errors, and Duration (RED signals) alongside hardware health.21

Extensibility and integrations

Checkmk includes over 2,000 officially maintained integrations for hardware (servers, storage, networks), software (databases, web servers), and cloud platforms (AWS, Azure, GCP). Users can develop custom integrations using Python.

Deployment

Checkmk is distributed as native packages for major Linux distributions (Debian, Ubuntu, RHEL, SLES), as a Docker image, and as a pre-configured Virtual appliance.20

See also

See also

References

References

  1. "Checkmk EULA". Checkmk GmbH. Retrieved May 31, 2023.
  2. "Checkmk – our story". Checkmk GmbH. Retrieved May 31, 2023.
  3. "Monitoring von Servern und Workstations" (in German). IP-Insider. April 6, 2020. Retrieved September 29, 2025.
  4. "Monitoring von Webseiten, Mailkonten und Applikationen" (in German). IP-Insider. May 18, 2020. Retrieved September 29, 2025.
  5. "Wie funktioniert das Überwachen von Schnittstellen und Ports mit Checkmk?" (in German). IP-Insider. September 7, 2020. Retrieved September 29, 2025.
  6. Huber, Mathias (March 9, 2011). "Nagios-Erweiterung Check_mk in Version 1.1.10". Linux Magazine (in German). Retrieved November 27, 2015.
  7. Rieger, Götz (November 3, 2012). "Einfach mal Nagios – Netzwerk-Monitoring mit OMD und Check_MK". c't (in German). p. 190. Archived from the original on November 27, 2015. Retrieved November 27, 2015.
  8. Siering, Peter (May 31, 2017). "Monitoring-System Check_MK in frischer Version 1.4.0". Heise Online (in German). Retrieved May 31, 2017.
  9. "Tribe29 becomes Checkmk". Comparitech. April 14, 2023. Retrieved September 22, 2025.
  10. "PSG Equity Announces Strategic Investment in Checkmk". PSG Equity. February 2025.
  11. Joseph, Irien (February 26, 2025). "PSG to pump capital into Germany's Checkmk". PE Hub. Retrieved April 2, 2026.
  12. "Checkmk 2.5.0 Release Notes". Checkmk GmbH. April 28, 2026. Retrieved April 29, 2026.
  13. Michael, Kai; Schlenkrich, Oliver; Wirtz, Michael (2021). "Monitoring and Extending the Hochschulstart Admission System". Proceedings of the 2021 EasyChair Conference. EasyChair. Retrieved September 22, 2025.
  14. "Checkmk editions". Checkmk GmbH. Retrieved March 17, 2026.
  15. Kettner, Mathias. "The Checkmk micro core (CMC)". Retrieved December 5, 2018.
  16. "Checkmk Documentation: The Monitoring Core". Checkmk GmbH.
  17. "The HW/SW Inventory". Checkmk GmbH. Retrieved May 1, 2026.
  18. "Checkmk aktualisieren – vorsichtig!" (in German). IP-Insider. November 2, 2020. Retrieved September 29, 2025.
  19. "Monitoring basics". Checkmk GmbH. Retrieved September 22, 2025.
  20. "Download". Checkmk GmbH. Retrieved May 31, 2023.
  21. "Monitoring OpenTelemetry metrics". Checkmk Documentation. Retrieved April 29, 2026.
External links