Martin Messer · 1 min read
FOSDEM 2026 Talk: Declarative VMs with NixOS
Have you ever felt the need for a virtual machine in your NixOS server environment? Watch our FOSDEM talk to learn how to run VMs declaratively on CTRL-OS.
Have you ever felt the need for a virtual machine in your NixOS server environment? Maybe the functionality you want is not available in NixOS? Maybe there’s a custom OS image for a service you want to provide? Maybe you just want to securely isolate your workload?
Watch our FOSDEM talk about the Declarative VM module in CTRL-OS below.
NixOS promises reproducible and declarative systems, but for VMs it just wasn’t there yet. To close this gap we built the ctrl-os.vms NixOS module, a solution to define generic virtual machines directly in your NixOS configuration. It works just like virtualisation.oci-containers, but for VMs instead of containers. 20 lines of Nix make it possible to run any Linux distribution you want as a VM on your NixOS host. To put a cherry on top you can use cloud-init, from our NixOS configuration to configure your guests declaratively, too! ctrl-os.vms is part of the ctrl-os-modules repository.
Check out the code on GitHub: https://github.com/cyberus-ctrl-os/ctrl-os-modules or watch the video below.