NixOS 18.03 on this machine (but not on the other one) has an issue with systemd-udev-settle hanging until its 3-minute timeout, so I'm running 17.09 for now. But I want Nix 2.0.2 still (17.09 runs 1.11.6). No problem, just add this near the top of /etc/nixos/configuration.nix (> means pre-existing line):

- - - -
> { config, pkgs, ... }:

let pkgsUnstable = import (pkgs.fetchFromGitHub {
owner = "NixOS"; repo = "nixpkgs-channels";
rev = "6db7f92cc2af827e8b8b181bf5ed828a1d0f141d";
sha256 = "1hpgn22j35mgfyrrkgyg28fm4mzllk5wfv5mrrn29kiglqb462fr";
}) {};
in

> {
nixpkgs.config.packageOverrides = pkgs: {
inherit (pkgsUnstable) nix;
};

> imports =
- - - -
Run nixos-rebuild switch, then check /etc/systemd/system/nix-daemon.service:



$ grep ExecStart /etc/systemd/system/nix-daemon.service
ExecStart=@/nix/store/vdvla43ppjf6gfsi8nx1zmac7rwq72yd-nix-2.0.2/bin/nix-daemon nix-daemon --daemon

Excellent.

#nixos