Nix Installer

nix-installer is an opinionated, experimental Nix installer.

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install

Status

nix-installer is pre-release and experimental. It is not ready for high reliability use! Please don't use it on a business critical machine!

Current and planned support:

• Multi-user Linux (aarch64 and x86_64) with systemd init, no SELinux
• Multi-user MacOS (aarch64 and x86_64)
  • Note: User deletion is currently unimplemented, you need to use a user with a secure token and dscl . -delete /Users/_nixbuild* where * is each user number.
• Valve Steam Deck
• Multi-user Linux (aarch64 and x86_64) with systemd init & SELinux
• Single-user Linux (aarch64 and x86_64)
• Others...

Installation Differences

Differing from the current official Nix installer scripts:

• Nix is installed with the nix-command and flakes features enabled in the nix.conf
• nix-installer stores an installation receipt (for uninstalling) at /nix/receipt.json as well as a copy of the install binary at /nix/nix-installer

Motivations

The current Nix installer scripts do an excellent job, however they are difficult to maintain. Subtle differences in the shell implementations, and certain characteristics of bash scripts make it difficult to make meaningful changes to the installer.

Our team wishes to experiment with the idea of an installer in a more structured language and see if this is a worthwhile alternative. Along the way, we are also exploring a few other ideas, such as:

• offering users a chance to review an accurate, calculated install plan
• having 'planners' which can create appropriate install plans
• keeping an installation receipt for uninstallation
• offering users with a failing install the chance to do a best-effort revert
• doing whatever tasks we can in parallel

So far, our explorations have been quite fruitful, so we wanted to share and keep exploring.

Usage

Install Nix with the default planner and options:

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install

Or, to download a platform specific Installer binary yourself:

$ curl -sL -o nix-installer https://install.determinate.systems/nix/nix-installer-x86_64-linux
$ chmod +x nix-installer

nix-installer will elevate itself if needed using sudo. If you use doas or please you may need to elevate nix-installer yourself.

nix-installer installs Nix by following a plan made by a planner. Review the available planners:

$ ./nix-installer install --help
Execute an install (possibly using an existing plan)

To pass custom options, select a planner, for example `nix-installer install linux-multi --help`

Usage: nix-installer install [OPTIONS] [PLAN]
       nix-installer install <COMMAND>

Commands:
  linux-multi
          A standard Linux multi-user install
  darwin-multi
          A standard MacOS (Darwin) multi-user install
  steam-deck
          A specialized install suitable for the Valve Steam Deck console
  help
          Print this message or the help of the given subcommand(s)
# ...

Planners have their own options and defaults, sharing most of them in common:

$ ./nix-installer install linux-multi --help
A standard Linux multi-user install

Usage: nix-installer install linux-multi [OPTIONS]

Options:
# ...
      --nix-build-user-count <NIX_BUILD_USER_COUNT>
          Number of build users to create
          
          [env: NIX_INSTALLER_NIX_BUILD_USER_COUNT=]
          [default: 32]

      --nix-build-user-id-base <NIX_BUILD_USER_ID_BASE>
          The Nix build user base UID (ascending)
          
          [env: NIX_INSTALLER_NIX_BUILD_USER_ID_BASE=]
          [default: 3000]
# ...

Planners can be configured via environment variable or command arguments:

$ curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | NIX_BUILD_USER_COUNT=4 sh -s -- install linux-multi --nix-build-user-id-base 4000
# Or...
$ NIX_BUILD_USER_COUNT=4 ./nix-installer install linux-multi --nix-build-user-id-base 4000

Uninstalling

You can remove a nix-installer-installed Nix by running

/nix/nix-installer uninstall

As a Github Action

You can use the nix-installer-action Github Action like so:

on:
  pull_request:
  push:
    branches: [main]

jobs:
  lints:
    name: Build
    runs-on: ubuntu-22.04
    steps:
    - uses: actions/checkout@v3
    - name: Install Nix
      uses: DeterminateSystems/nix-installer-action@main
      with:
        # Allow the installed Nix to make authenticated Github requests.
        # If you skip this, you will likely get rate limited.
        github-token: ${{ secrets.GITHUB_TOKEN }}
    - name: Run `nix build`
      run: nix build .

Building

Since you'll be using nix-installer to install Nix on systems without Nix, the default build is a static binary.

Build a portable binary on a system with Nix:

nix build -L github:determinatesystems/nix-installer#nix-installer-static

Then copy the result/bin/nix-installer to the machine you wish to run it on.

You can also add nix-installer to your system without having Nix:

RUSTFLAGS="--cfg tokio_unstable" cargo install nix-installer
nix-installer --help

To make this build portable, pass --target x86_64-unknown-linux-musl.

We currently require --cfg tokio_unstable as we utilize Tokio's process groups, which wrap stable std APIs, but are unstable due to it requiring an MSRV bump.

As a library

Add nix-installer to your dependencies:

cargo add nix-installer

Building a CLI? Check out the cli feature flag for clap integration.

You'll also need to edit your .cargo/config.toml to use tokio_unstable:

# .cargo/config.toml
[build]
rustflags=["--cfg", "tokio_unstable"]

Then it's possible to review the documentation:

cargo doc --open -p nix-installer

Documentation is also available via nix build:

nix build github:DeterminateSystems/nix-installer#nix-installer.doc
firefox result-doc/nix-installer/index.html