Deprecate in favor of native Fedora Nix package (F44 Change)

[alexandre-hallaine]

Fedora 44 introduces nix as an official package, providing a managed path for both multi-user (daemon) and single-user/rootless setups. This upstream integration makes the manual bind-mount and script-based approach of nix-toolbox redundant for Fedora users.

I suggest deprecating this project or pivoting to a wrapper around the official packages:

• Fedora Change: https://fedoraproject.org/wiki/Changes/Nix_package_tool
• Package Source: https://src.fedoraproject.org/rpms/nix

The official nix-core package now supports rootless operation compatible with rpm-ostree environments without requiring custom Containerfile logic.

[lpchaim]

Just gave this a try on the latest bazzite build out of curiosity and nix-core doesn't work out of the box FWIW, still glad this is now a thing though and it's probably a matter of time

Installed nix-core

sudo rpm-ostree install nix-core

Rebooted, tried to run home-manager as a test, nix refuses to run due to the fact /home is a symlink to /var/home

> nix run github.com:nix-community/home-manager -- --help
warning: '/nix/var/nix' does not exist, so Nix will use '/home/lpchaim/.local/share/nix/root' as a chroot store
error: the path '"/home"' is a symlink; this is not allowed for the Nix store and its parent directories

[alexandre-hallaine]

This works well inside a toolbox (tested on a fresh Fedora 43 image):

sudo dnf install nix --exclude nix-daemon
sudo usermod -aG nixbld $USER

(Exit and re-enter the toolbox for the group change to apply).

[thrix]

@alexandre-hallaine thanks for the suggestion, I am aware of the change. I will try it out and if works we can definitely use that. I want to add support also for some other toolbox variants for other distros, so there it still might be useful to fallback to the current way of installing nix.

There are some other things I want to share with the project around home manager and some best practices to use it to manage home and parts of Fedora Atomic Desktop system software using home manager (my primary usage).

[thrix]

Just gave this a try on the latest bazzite build out of curiosity and nix-core doesn't work out of the box FWIW, still glad this is now a thing though and it's probably a matter of time

Installed nix-core

sudo rpm-ostree install nix-core
Rebooted, tried to run home-manager as a test, nix refuses to run due to the fact /home is a symlink to /var/home

nix run github.com:nix-community/home-manager -- --help
warning: '/nix/var/nix' does not exist, so Nix will use '/home/lpchaim/.local/share/nix/root' as a chroot store
error: the path '"/home"' is a symlink; this is not allowed for the Nix store and its parent directories

@lpchaim thanks, that issue is known, you need to workaround via:

https://github.com/thrix/nix-toolbox/blob/main/nix.sh#L15

[thrix]

One more thing I realized is that by installing nix from fedora packages the only thing it will replace is nix installation itself. The bind mount is used to have a persistant nix store when you need to recreate the nix toolbox container. So yeah, this project will live on even with that change.

[thrix]

@lpchaim some other tools might not like it, but it is usally a bug:

https://gitlab.com/gitlab-org/cli/-/merge_requests/2795

Actually, this is the only tool I had to fix and I am using this setup for 2 years or so.

[juhp]

One more thing I realized is that by installing nix from fedora packages the only thing it will replace is nix installation itself. The bind mount is used to have a persistant nix store when you need to recreate the nix toolbox container. So yeah, this project will live on even with that change.

Well the /nix bind mount will be coming to Fedora too, I just didn't have enough time to ship it yet - I think it is already in my copr repo - and didn't want to risk complicating the F44 Change at the time.

---

Another case in point is that newer nix (2.32+) will not build on older fedora/epel, that may be another argument for using the official fedora nix or nix-core package at least.

[thrix]

Ack, I will try it out soon. Thx for the feedback @juhp

[zeitue]

Will the changes in Fedora 44 mean the Nix package manager will work on Fedora SilverBlue?

[juhp]

Will the changes in Fedora 44 mean the Nix package manager will work on Fedora SilverBlue?

That may be off-topic here, but if you are asking about /nix then currently no - it is still non-trivial to add the bind mount directory in SB - I think it is easier in bootc based images though. Just layering nix-core works fine though.

[alexandregv]

In case this helps someone passing by, I got /nix to work on Silverblue 44 using a custom image built with BlueBuild. Then the nix and nix-daemon packages work fine.

Bind-mount unit: github.com/alexandregv/bluebuild-images/files/systemd/system/nix.mount
Nix setup: github.com/alexandregv/bluebuild-images/recipes/modules/nix.yaml
Full recipe: github.com/alexandregv/bluebuild-images/recipes/silverblue-cosmic-nix.yaml

Of course it's a bit heavy to build and maintain a custom image, so nix-toolbox might still be useful for this case.

[thrix]

@alexandregv btw I use also bluebuild :) https://github.com/thrix/workstation, but yeah, for nix usage I prefer this project, for obvious reasons :)