KVM builds supported on nixbuild.net

Posted on October 1, 2021 by Rickard Nilsson

Less than two weeks ago, we announced support for ARM builds on nixbuild.net. Today we are excited to announce another early access feature — support for builds that use KVM!

KVM support is something that almost no public CI/CD provider offers, so we are very happy to be able to make this available to our users.

For NixOS users and developers, this is especially valuable since it makes it possible to run integration tests based on the powerful testing framework found in nixpkgs/NixOS.

KVM builds are currently in an Early Access phase. If you want to try it out, contact us at [email protected]. Anyone is free to request access, but there might be waiting time depending on interest. During Early Access, KVM builds are priced and handled exactly as standard builds. The final pricing and price model for builds that require KVM has not been settled yet.

So far KVM builds are only supported on x86_64-linux, not on ARM.


Once you’ve gained access to running KVM builds, configuring your Nix client is simple. You just need to mark your eu.nixbuild.net remote builder with the kvm system feature. And if you want to run NixOS integration tests you’ll need the nixos-test feature too. For more detailed configuration descriptions see the documentation.

KVM builds in GitHub Actions

The nixbuild.net GitHub Action has been updated to support KVM builds too. If you’ve been granted access to KVM builds, all you have to do is to make sure you use the latest release of nixbuild-action. No extra configuration is needed to run KVM builds, or NixOS integration tests, in GitHub Actions.