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Werk #20127: Add support for running the Relay on Windows

Component Relay
Title Add support for running the Relay on Windows
Date Jun 18, 2026
Level Prominent Change
Class New Feature
Compatibility Compatible - no manual interaction needed
Checkmk versions & editions
3.0.0b1
Not yet released
Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT
2.5.0p10
Not yet released
Checkmk Ultimate, Checkmk Cloud, Checkmk Ultimate MT

You can now run a Checkmk Relay on a Windows host. A dedicated Windows installer is provided, and adding a Windows relay is guided by a new wizard in Setup.

What this means

Until now the Relay ran on Linux only. With this release you can also deploy a Relay on Windows. On Windows the relay runs inside a dedicated Ubuntu 24.04 WSL2 distribution that the installer sets up for you - from the site's point of view the relay registers and behaves like any other relay.

Adding a Windows relay

In Setup, when adding a relay, select a Windows operating system (Windows Server 2022 or Windows Server 2025). The wizard then guides you through three steps:

  1. Download the Windows installer from the Relay setup wizard, which is shipped with your site.
  2. Make sure WSL2 is enabled on the target host.
  3. Run the installer, which registers the relay with your site.

The installer can be run interactively - a dialog collects the relay name, the relay image tag, the target site host (and optional port), the site name, and the authentication (token or user/password) - or silently via msiexec properties for unattended deployment.

Prerequisites

  • A supported Windows version with WSL2 (Windows Server 2022 or 2025)
  • WSL2 enabled on the host
  • Administrator rights on the target host: the installer writes under Program Files, imports a WSL distribution, and registers a scheduled task

Good to know

  • The relay engine updates automatically, just like on Linux: it checks the site version and pulls the matching relay container image from Docker Hub inside the WSL2 distribution.
  • The Windows installation stack itself (the MSI and its WSL2 distribution) does not support in-place upgrades yet. To move to a newer installer, uninstall the existing one and install the new one.
  • After a reboot, the relay comes back up automatically. The installer registers a scheduled task that starts the relay at machine boot, so no interactive logon is required - this also works on headless servers.

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