NixOS Install Basics: From ISO to First Boot

NixOS is a Linux distro built around the Nix package manager, where every system state — packages, services, users — is defined declaratively in configuration.nix. Atomic upgrades, rollback in seconds, reproducible across machines. The trade-off is the learning curve.

Prerequisites

• A VM or physical host with 2 vCPU, 4 GiB RAM, 20 GiB disk.
• nixos-minimal-x.yy-x86_64-linux.iso from nixos.org/download.
• UEFI recommended.

Step 1: Boot the ISO

Boot from USB/CD. You drop to a root shell with networking, ssh, and a curated tool set already in place.

sudo -i
loadkeys us

Confirm internet:

ping -c 2 nixos.org

For wifi:

systemctl start wpa_supplicant
wpa_cli                # then `add_network`, `set_network 0 ssid "..."`, etc.

Step 2: Partition (UEFI + ext4)

parted /dev/nvme0n1 -- mklabel gpt
parted /dev/nvme0n1 -- mkpart ESP fat32 1MiB 512MiB
parted /dev/nvme0n1 -- set 1 esp on
parted /dev/nvme0n1 -- mkpart primary 512MiB 100%

mkfs.fat -F32 -n boot /dev/nvme0n1p1
mkfs.ext4 -L nixos /dev/nvme0n1p2

mount /dev/disk/by-label/nixos /mnt
mkdir -p /mnt/boot
mount /dev/disk/by-label/boot /mnt/boot

Step 3: Generate the starting config

nixos-generate-config --root /mnt
ls /mnt/etc/nixos
# configuration.nix  hardware-configuration.nix

hardware-configuration.nix is auto-detected (CPU, disks, filesystems) — leave it alone. Edit configuration.nix:

nano /mnt/etc/nixos/configuration.nix

A minimal server-shaped config:

{ config, pkgs, ... }:
{
  imports = [ ./hardware-configuration.nix ];

  boot.loader.systemd-boot.enable = true;
  boot.loader.efi.canTouchEfiVariables = true;

  networking.hostName = "nixos-host";
  networking.networkmanager.enable = true;

  time.timeZone = "Asia/Riyadh";
  i18n.defaultLocale = "en_US.UTF-8";

  users.users.ops = {
    isNormalUser = true;
    extraGroups  = [ "wheel" "networkmanager" ];
    openssh.authorizedKeys.keys = [
      "ssh-ed25519 AAAA... your@workstation"
    ];
  };

  services.openssh = {
    enable = true;
    settings = {
      PermitRootLogin = "no";
      PasswordAuthentication = false;
    };
  };

  environment.systemPackages = with pkgs; [
    vim git htop curl tmux
  ];

  networking.firewall.allowedTCPPorts = [ 22 ];

  system.stateVersion = "24.05";
}

Step 4: Install

nixos-install

nixos-install builds the entire system from your config, copies it to /mnt, and asks for the root password at the end. This takes 10–20 minutes the first time.

When it finishes, reboot:

reboot

Remove the USB during POST.

Step 5: First boot and ssh in

Log in as root with the password you set, then passwd ops to set the operator's password, and verify ssh from your workstation:

ssh ops@nixos-host
sudo nixos-version

Verify

nixos-version
nixos-rebuild list-generations
systemctl --failed
journalctl -p err -b

Conclusion

A working NixOS host in two files (configuration.nix + hardware-configuration.nix) — every package, every user, every service explicit. The first install is slow because Nix is downloading a closure; subsequent rebuilds are fast.

Next steps

• Manage system state via configuration.nix declaratively.
• For more conventional distros see Install Debian 12 or Install Arch Linux.
• For container-shaped declarative deploys see Kubernetes k3s.