* Fancy-fy the README a bit

* Ensure GH doesn't make flake URLs poorly formatted

2023-03-16 17:08:27 +00:00

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The Determinate Nix Installer

nix-installer is an opinionated alternative to the official Nix install scripts.

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

The nix-installer tool is ready to use in a number of environments:

Platform	Multi User	`root` only	Maturity
Linux (x86_64 & aarch64)	✓ (via systemd)	✓	Stable
MacOS (x86_64 & aarch64)	✓		Stable (See note)
Valve Steam Deck (SteamOS)	✓		Stable
WSL2 (x86_64 & aarch64)	✓ (via systemd)	✓	Stable
Podman Linux Containers	✓ (via systemd)	✓	Stable
Docker Containers		✓	Stable
Linux (i686)	✓ (via systemd)	✓	Unstable

Note

On MacOS only, removing users and/or groups may fail if there are no users who are logged in graphically.

Installation Differences

Differing from the current official Nix installer scripts:

In nix.conf:
- the nix-command and flakes features are enabled
- bash-prompt-prefix is set
- auto-optimise-store is set to true
- extra-nix-path is set to nixpkgs=flake:nixpkgs
an installation receipt (for uninstalling) is stored at /nix/receipt.json as well as a copy of the install binary at /nix/nix-installer
nix-channel --update is not run, ~/.nix-channels is not provisioned
NIX_SSL_CERT_FILE is set in the various shell profiles if the ssl-cert-file argument is used.

Motivations

The current Nix install 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

Note

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
          A planner for Linux installs
  steam-deck
          A planner suitable for the Valve Steam Deck running SteamOS
  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 --help
A planner for Linux installs

Usage: nix-installer install linux [OPTIONS]

Options:
# ...
      --nix-build-group-name <NIX_BUILD_GROUP_NAME>
          The Nix build group name
          
          [env: NIX_INSTALLER_NIX_BUILD_GROUP_NAME=]
          [default: nixbld]

      --nix-build-group-id <NIX_BUILD_GROUP_ID>
          The Nix build group GID
          
          [env: NIX_INSTALLER_NIX_BUILD_GROUP_ID=]
          [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_GROUP_NAME=nixbuilder sh -s -- install linux-multi --nix-build-group-id 4000
# Or...
$ NIX_BUILD_GROUP_NAME=nixbuilder ./nix-installer install linux-multi --nix-build-group-id 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
    - name: Run `nix build`
      run: nix build .

Without systemd (Linux only)

Warning

When --init none is used, only root or users who can elevate to root privileges can run Nix:
sudo -i nix run nixpkgs#hello

If you don't use systemd, you can still install Nix by explicitly specifying the linux plan and --init none:

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install linux --init none

In a container

In Docker/Podman containers or WSL2 instances where an init (like systemd) is not present, pass --init none.

Warning

When --init none is used, only root or users who can elevate to root privileges can run Nix:
sudo -i nix run nixpkgs#hello

For Docker containers (without an init):

# Dockerfile
FROM ubuntu:latest
RUN apt update -y
RUN apt install curl -y
COPY nix-installer /nix-installer
RUN /nix-installer install linux --init none --no-confirm
ENV PATH="${PATH}:/nix/var/nix/profiles/default/bin"
RUN nix run nixpkgs#hello

Podman containers require sandbox = false in your Nix.conf.

For podman containers without an init:

# Dockerfile
FROM ubuntu:latest
RUN apt update -y
RUN apt install curl -y
COPY nix-installer /nix-installer
RUN /nix-installer install linux --extra-conf "sandbox = false" --init none --no-confirm
ENV PATH="${PATH}:/nix/var/nix/profiles/default/bin"
RUN nix run nixpkgs#hello

For Podman containers with a systemd init:

# Dockerfile
FROM ubuntu:latest
RUN apt update -y
RUN apt install curl systemd -y
COPY nix-installer /nix-installer
RUN /nix-installer install linux --extra-conf "sandbox = false" --no-start-daemon --no-confirm
ENV PATH="${PATH}:/nix/var/nix/profiles/default/bin"
RUN nix run nixpkgs#hello
CMD [ "/usr/sbin/init" ]

In WSL2

If systemd is enabled it's possible to install Nix as normal using the command at the top of this document:

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

If systemd is not enabled, pass --init none at the end of the command:

Warning

When --init none is used, only root or users who can elevate to root privileges can run Nix:
sudo -i nix run nixpkgs#hello

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install linux --init none

Skip confirmation

If you'd like to bypass the confirmation step, you can apply the --no-confirm flag:

curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install --no-confirm

This is especially useful when using the installer in non-interactive scripts.

Building a binary

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

Build a portable Linux binary on a system with Nix:

# to build a local copy
nix build -L ".#nix-installer-static"
# to build the remote main development branch
nix build -L "github:determinatesystems/nix-installer#nix-installer-static"
# for a specific version of the installer:
export NIX_INSTALLER_TAG="v0.5.0"
nix build -L "github:determinatesystems/nix-installer/$NIX_INSTALLER_TAG#nix-installer-static"

On Mac:

# to build a local copy
nix build -L ".#nix-installer"
# to build the remote main development branch
nix build -L "github:determinatesystems/nix-installer#nix-installer"
# for a specific version of the installer:
export NIX_INSTALLER_TAG="v0.5.0"
nix build -L "github:determinatesystems/nix-installer/$NIX_INSTALLER_TAG#nix-installer"

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

You can also add nix-installer to a system without Nix via cargo:

# to build and run a local copy
RUSTFLAGS="--cfg tokio_unstable" cargo run -- --help
# to build the remote main development branch
RUSTFLAGS="--cfg tokio_unstable" cargo install --git https://github.com/DeterminateSystems/nix-installer
nix-installer --help
# for a specific version of the installer:
export NIX_INSTALLER_TAG="v0.5.0"
RUSTFLAGS="--cfg tokio_unstable" cargo install --git https://github.com/DeterminateSystems/nix-installer --tag $NIX_INSTALLER_TAG
nix-installer --help

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

Note

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

Warning

Use as a library is still experimental, if you're using this, please let us know and we can make a path to stablization.

Add nix-installer to your dependencies:

cargo add nix-installer

If you are 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 as we utilize Tokio's process groups, which wrap stable std APIs, but are unstable due to it requiring an MSRV bump:

# .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

Quirks

While nix-installer tries to provide a comprehensive and unquirky experience, there are unfortunately some issues which may require manual intervention or operator choices.

Using MacOS remote SSH builders, Nix binaries are not on `$PATH`

When connecting to a Mac remote SSH builder users may sometimes see this error:

$ nix store ping --store "ssh://$USER@$HOST"
Store URL: ssh://$USER@$HOST
zsh:1: command not found: nix-store
error: cannot connect to '$USER@$HOST'

The way MacOS populates the PATH environment differs from other environments. (Some background)

There are two possible workarounds for this:

(Preferred) Update the remote builder URL to include the remote-program parameter pointing to nix-store. For example:
```
nix store ping --store "ssh://$USER@$HOST?remote-program=/nix/var/nix/profiles/default/bin/nix-store"
```
If you are unsure where the nix-store binary is located, run which nix-store on the remote.
Update /etc/zshenv on the remote so that zsh populates the Nix path for every shell, even those that are neither interactive or login:
```
# Nix
if [ -e '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh' ]; then
    . '/nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh'
fi
# End Nix
```
This strategy has some behavioral caveats, namely, `$PATH` may have unexpected contents

For example, if PATH gets unset then a script invoked, PATH may not be as empty as expected:
```
$ cat example.sh     
#! /bin/zsh
echo $PATH
$ PATH= ./example.sh 
/Users/ephemeraladmin/.nix-profile/bin:/nix/var/nix/profiles/default/bin:
```
This strategy results in Nix's paths being present on $PATH twice and may have a minor impact on performance.

Diagnostics

The goal of the Determinate Nix Installer is to successfully and correctly install Nix. The curl | sh pipeline and the installer collects a little bit of diagnostic information to help us make that true.

Here is a table of the diagnostic data we collect:

Field	Use
`version`	The version of the Determinate Nix Installer.
`planner`	The method of installing Nix (`linux`, `macos`, `steam-deck`)
`configured_settings`	The names of planner settings which were changed from their default. Does not include the values.
`os_name`	The running operating system.
`os_version`	The version of the operating system.
`triple`	The architecture/operating system/binary format of your system.
`is_ci`	Whether the installer is being used in CI (e.g. GitHub Actions).
`action`	Either `Install` or `Uninstall`.
`status`	One of `Success`, `Failure`, `Pending`, or `Cancelled`.
`failure_chain`	A high level description of what the failure was, if any. For example: `Command("diskutil")` if the command `diskutil list` failed.

To disable diagnostic reporting, set the diagnostics URL to an empty string by passing --diagnostic-endpoint="" or setting NIX_INSTALLER_DIAGNOSTIC_ENDPOINT="".

You can read the full privacy policy for Determinate Systems, the creators of the Determinate Nix Installer, here.

15 KiB Raw Blame History

The Determinate Nix Installer

Installation Differences

Motivations

Usage

Uninstalling

As a Github Action

Without systemd (Linux only)

In a container

In WSL2

Skip confirmation

Building a binary

As a library

Quirks

Using MacOS remote SSH builders, Nix binaries are not on $PATH

Diagnostics

15 KiB

Raw Blame History

Using MacOS remote SSH builders, Nix binaries are not on `$PATH`