Proxmox on NixOS

This project is a port of the Proxmox Hypervisor on NixOS.

⚠️ Proxmox-NixOS is still experimental and we do not advise running it on production machines. Do it at your own risk and only if you are ready to fix issues by yourself.

🚦 Supported features

Proxmox-NixOS has been tested on real hardware with most basic features of Proxmox (booting VMs, user management, etc), more involved setups (clusters, HA, etc) are still under development and testing.

While we export other architectures for convenience of the user, we only support x86_64-linux for now;

🗃️ Cache

Some Proxmox packages have a quite power intensive build process. We make a cache available to download directly the artifacts:

• address: https://cache.saumon.network/proxmox-nixos
• public key: proxmox-nixos:nveXDuVVhFDRFx8Dn19f1WDEaNRJjPrF2CPD2D+m1ys=

🚀 Quick start

With npins

Add proxmox-nixos as a dependency of your npins project.

$ npins add github SaumonNet proxmox-nixos -b main
[INFO ] Adding 'proxmox-nixos' …
    repository: https://github.com/SaumonNet/proxmox-nixos.git
    branch: main
    revision: ...
    url: https://github.com/saumonnet/proxmox-nixos/archive/$revision.tar.gz
    hash: ...

Below is a fragment of a NixOS configuration that enables Proxmox VE.

# file: configuration.nix
{ pkgs, lib, ... }:
let
    sources = import ./npins;
    proxmox-nixos = import sources.proxmox-nixos;
in
{
  imports = [ proxmox-nixos.nixosModules.proxmox-ve ];
  services.proxmox-ve.enable = true;
  nixpkgs.overlays = [
    proxmox-nixos.overlays.x86_64-linux
  ];
  # The rest of your configuration...
}

With Flakes

Below is a fragment of a NixOS configuration that enables Proxmox VE.

{
  description = "A flake with Proxmox VE enabled";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    proxmox-nixos.url = "github:SaumonNet/proxmox-nixos";
  };

  outputs = { self, nixpkgs, proxmox-nixos, ...}: {
    nixosConfigurations = {
      yourHost = nixpkgs.lib.nixosSystem rec {
        system = "x86_64-linux";
        modules = [

          proxmox-nixos.nixosModules.proxmox-ve

          ({ pkgs, lib, ... }: {
            services.proxmox-ve.enable = true;
            nixpkgs.overlays = [
              proxmox-nixos.overlays.${system}
            ];

            # The rest of your configuration...
          })
        ];
      };
    };
  };
}

⚠️ Do not override the nixpkgs-stable input of the flake, as the only tested and supported version of Proxmox-NixOS is with the upstream stable NixOS release.

🌐 Networking

To get internet in your VMs, you need to add a network device to the VM, connected to a bridge. To get this working, follow this 2 steps:

1. Create the bridge in System->Network->Create->Linux Bridge. This operation has no effect on your system and is just a quirk for Proxmox to know the existence of your bridge.
2. Configure your networking through NixOS configuration so that the bridge you created in the Proxmox web interface actually exists!

Example NixOS networking configurations

Any kind of advanced networking configuration is possible through the usual NixOS options, but here are basic examples that can get you started:

With systemd-networkd

systemd.network.networks."10-lan" = {
    matchConfig.Name = [ "ens18" ];
    networkConfig = {
    Bridge = "vmbr0";
    };
};

systemd.network.netdevs."vmbr0" = {
    netdevConfig = {
        Name = "vmbr0";
        Kind = "bridge";
    };
};

systemd.network.networks."10-lan-bridge" = {
    matchConfig.Name = "vmbr0";
    networkConfig = {
    IPv6AcceptRA = true;
    DHCP = "ipv4";
    };
    linkConfig.RequiredForOnline = "routable";
};

With scripted networking

networking.bridges.vmbr0.interfaces = [ "ens18" ];
networking.interfaces.vmbr0.useDHCP = lib.mkDefault true;

🧱 Declarative VMs

Using the module virtualisation.proxmox

This solution is available even for the admin of a particular VM with only a restricted API access to the Proxmox Hypervisor.

The utility nixmoxer allows one to bootstrap NixOS virtual machines on an existing Proxmox hypervisor, using the API.

First, configure the virtual machine settings using the options of the NixOS module virtualisation.proxmox of your nixosConfigurations.myvm:

# myvm.nix
{ config, ... }:

{
  imports = [ ./disko.nix ];

  networking.hostName = "myvm";

  virtualisation.proxmox = {
    node = "myproxmoxnode";
    iso = <derivation for your iso>;
    vmid = 101;
    memory = 4096;
    cores = 4;
    sockets = 2;
    net = [
      {
        model = "virtio";
        bridge = "vmbr0";
      }
    ];
    scsi = [ { file = "local:16"; } ]; # This will create a 16GB volume in 'local'
  };

  # The rest of your configuration...
}

You can find an exhaustive list of options in modules/declarative-vms/options.nix, or in the official documentation of the Proxmox API.

Then configure the access to the Proxmox API:

# nixmoxer.conf
host=192.168.0.3
user=root
password=<password>
verify_ssl=0

Now you can bootstrap myvm using nixmoxer:

$ nix run github:SaumonNet/proxmox-nixos#nixmoxer -- [--flake] myvm

nixmoxer will setup the VM on the Proxmox node and attach the specified iso. Instead of specified an iso, setting autoInstall = true; will automatically generate an iso that will automatically install the configuration to the VM being bootstrapped.

⚠️ nixmoxer shall only be used for the initial bootstraping of a VM, the NixOS VM can be rebuilt with usual tools like nixos-rebuild, colmena, etc. Changes to the virtualisation.proxmox options after the boostraping have no impact.

Using the module services.proxmox-ve.vms

This solution is only available for the admin of a Proxmox Hypervisor on NixOS.

This configuration will create two VMs on a Proxmox-NixOS Hypervisor. Then you can attach an iso and configuration your VMs as usual.

# configuration.nix
{
  services.proxmox-ve = {
    enable = true;
    vms = {
      myvm1 = {
        vmid = 100;
        memory = 4096;
        cores = 4;
        sockets = 2;
        kvm = false;
        net = [
          {
            model = "virtio";
            bridge = "vmbr0";
          }
        ];
        scsi = [ { file = "local:16"; } ];
      };
      myvm2 = {
        vmid = 101;
        memory = 8192;
        cores = 2;
        sockets = 2;
        scsi = [ { file = "local:32"; } ];
      };
    };
  };

  # The rest of your configuration...
}

You can find an exhaustive list of options in modules/declarative-vms/options.nix, or in the official documentation of the Proxmox API.

⚠️ The current limitation is that if for instance VM myvm1 has already been initialised, subsequent changes to the configuration in services.proxmox-ve.vms.myvm1 will have no impact.

Note

Truly declarative configuration of virtual machines is very difficult with Proxmox-NixOS because there is essentially 2 sources of truth (the NixOS configuration and the Proxmox web interface) that have to be reconciliated. If you want truly declarative VMs configurations we recommend the amazing project microvms.nix.

🚧 Roadmap

• Support for clusters / HA with Ceph
• More coverage of NixOS tests
• Proxmox backup server

🔧 Maintainance

Most packages are regularly and automatically updated thanks to a modified version of the nixpkgs-update bot, whose logs are available here.

📬 Help / Discussions

There is a matrix room for discussions about Proxmox-NixOS.

Thanks

This project has received support from NLNet.