Installing and testing NixOS

NixOS

NixOS is a minimal and flexible Linux distribution which doesn’t use any of the existing package manager.

NixOS is a Linux distribution with a unique approach to package and configuration management. Built on top of the Nix package manager, it is completely declarative, makes upgrading systems reliable, and has many other advantages.

I wanted to test NixOS and see if it could be a candidate for a very minimal KVM hypervisor running just Qemu, libvirt and Apache CloudStack.

With this post I just wanted to share how you can quickly install NixOS inside a VirtualBox VM.

VirtualBox

On my desktop and laptop I usually use VirtualBox to quickly test something inside Virtual Machines. In this case I downloaded the NixOS minimal 64-bit ISO and created a VM:

  • 1024MB of memory
  • 8GB SATA disk
  • NixOS ISO attached

Installation

After you start the VM it will boot from the ISO. You will then find yourself in a root prompt saying just nixos.

The first step is to format your disk and mount it under /mnt.

parted /dev/sda mklabel msdos
parted /dev/sda mkpart primary 0% 100%
mkfs.xfs /dev/sda1
mount /dev/sda1 /mnt

If you have that done you can run:

nixos-generate-config

This will generate /mnt/etc/nixos/configuration.nix from where you can configure your OS.

This is what I used as my configuration:

{ config, pkgs, ... }:

{
  imports = [
      ./hardware-configuration.nix
    ];

  boot.loader.grub.enable = true;
  boot.loader.grub.version = 2;
  boot.loader.grub.device = "/dev/sda";

  boot.kernelPackages = pkgs.linuxPackages_4_1;

  time.timeZone = "Europe/Amsterdam";

  networking.firewall.enable = false;

  environment.systemPackages = with pkgs; [
    wget git screen ceph
  ];

  services.openssh.enable = true;
  services.openssh.permitRootLogin = "yes";

  virtualisation.libvirtd.enable = true;
  virtualisation.libvirtd.extraOptions = ["-l"];
  virtualisation.libvirtd.extraConfig = "listen_tls = 0\nlisten_tcp = 1";

  system.stateVersion = "15.09";
}

A minimal installation with just OpenSSH and libvirt installed.

Now you can actually install NixOS:

nixos-install

After a few minutes you will be prompted for a root-password and that’s it!

Reboot and you have a running NixOS installation 🙂

Published by

Wido den Hollander

I am the CTO at PCextreme B.V. and i will keep this blog just to post some interesting information about my daily work on Linux (and other) systems.