features/src/nix/README.md

Nix Package Manager (nix)

Installs the Nix package manager and optionally a set of packages.

Example Usage

"features": {
    "ghcr.io/devcontainers/features/nix:1": {}
}

Options

Options Id	Description	Type	Default Value
version	Version of Nix to install.	string	latest
multiUser	Perform a multi-user install (instead of single user)	boolean	true
packages	Optional comma separated list of Nix packages to install in profile.	string	-
flakeUri	Optional URI to a Nix Flake to install in profile.	string	-
extraNixConfig	Optional comma separated list of extra lines to add to /etc/nix/nix.conf.	string	-

OS Support

This Feature should work on recent versions of Debian/Ubuntu, RedHat Enterprise Linux, Fedora, RockyLinux, and Alpine Linux.

Location of Flakes

Currently flakeUri works best with a remote URI (e.g., github:nixos/nixpkgs/nixpkgs-unstable#hello) as local files need to be in the image.

Proposed support for lifecycle hooks in Features (#60) would allow for expressions files or Flakes to exist in the source tree to be automatically installed on initial container startup, but today you will have to manually add the appropriate install command to postCreateCommand to your devcontainer.json instead.

Multi-user vs. single-user installs

This Dev Container Feature supports two installation models for Nix: multi-user and single user. Multi-user is the default, but each has pros and cons.

Installation Model	Pros	Cons
Multi-User	Nix can be used with any user including root. Also still works if the UID or GID of any user is updated.	Only works with Nix 2.11 and up due to a Nix installer limitation. Container must run either: run as root (but remoteUser in devcontainer.json can be non-root), or includes sudo with the remoteUser being configured to use it. Note that automated start of the nix-daemon requires passwordless sudo if the container itself (e.g., containerUser) is not running as root. Manual startup using sudo can require a password, however (more next).
Single-User	Does not require the container to run as root or sudo to be included in the image.	Only works with the user specified in the remoteUser property or an auto-detected user. If this user's UID/GID is updated, that user will no longer be able to work with Nix. This is primarily a consideration when running on Linux where the UID/GID is sync'd to the local user.

Manually starting the Nix daemon

If you have sudo in your base image, but have a password set so automatic startup is not possible, you can manually start the Nix daemon by running the following command in a terminal:

sudo /usr/local/share/nix-entrypoint.sh

This same command can be used to restart the daemon if it has stopped for some reason. Logs are available at /tmp/nix-daemon.log.

OS Support

This Feature should work on recent versions of Debian/Ubuntu-based distributions with the apt package manager installed.

bash is required to execute the install.sh script.

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Note: This file was auto-generated from the devcontainer-feature.json. Add additional notes to a NOTES.md.