Install NIX Package Manager on Alpine Linux

• alpine 3.17.1 x86-64
• linux 6.1.8-lts w/zfs
• edge, testing apk repos enabled

apk add sudo
apk add shadow
apk add bash

• pkg sudo is needed; aliasing /usr/bin/doas does not work
• pkg shadow provides groupadd and related tools, needed by nix install script
• the install script might not behave with ash so install bash

Alpine does not use systemd. Copy this file to /etc/init.d/nix-daemon and make it executable. I copied this script from the testing package in the alpine package repository.

#!/sbin/openrc-run
description="Nix multi-user support daemon"

command="/usr/sbin/nix-daemon"
command_background="yes"
pidfile="/run/$RC_SVCNAME.pid"

For some reason, the multi-user install does not install the nix-daemon binary in a system directory, instead it gets installed here:

/root/.nix-profile/bin/nix-daemon

I chose to copy this binary to /usr/sbin which seems to work.

Enable and start the service:

# run as root or sudo
chmod a+rx /etc/init.d/nix-daemon
cp /root/.nix-profile/bin/nix-daemon /usr/sbin
rc-update  add nix-daemon
rc-service nix-daemon start

At this point, you should make sure that your userid has been added to the nixblk group. Also we need to open up the permissions on the nix-daemon socket so nixbld group members can communicate with the daemon.

Follow the instructions the script emits - run it as root the first time:

# nix installer should have emitted this text:
#   Alright! We're done!
#   Try it! Open a new terminal, and type:
#   nix-shell -p nix-info --run "nix-info -m"

The output should look something similar to the following:

• system: `"x86<sub>64</sub>-linux"`
• host os: `Linux 6.1.8-0-lts, Alpine Linux, noversion, nobuild`
• multi-user?: `yes`
• sandbox: `yes`
• version: `nix-env (Nix) 2.13.1`
• channels(root): `"nixpkgs"`
• nixpkgs: `/root/.nix-defexpr/channels/nixpkgs`

Now, before we try running nix as non-root user, let's add ourselves to the nixblk group and reboot. This will ensure our userid is in the nixbld group and that all running shells have picked it up. Rebooting after this will also test that our service starts correctly on a fresh boot.

sudo adduser YOURUSERID nixbld
reboot (or do a safe shutdown however you usually do it)

Now, let's try the first steps documentation from https://nixos.org/guides/ad-hoc-developer-environments.html as our default user.

$ hello
The program ‘hello’ is currently not installed.

$ nix-shell -p hello

[nix-shell:~]$ hello
Hello, world!

[nix-shell:~]$ exit
exit

$ hello
The program ‘hello’ is currently not installed.

Now we can try running a real application inside of nix-shell and then we will install it so it's available outside of the nix-shell application.

You can create your own nix.conf file in ~/.config/nix/nix.conf. This file can contain a variety of settings. Here are some things I learned.

I tried to use flakes but I got an error. The error said that I needed to enable an experimental option. Specifically:

$ nix run nixpkgs#hello
error: experimental Nix feature 'nix-command' is disabled; use '--extra-experimental-features nix-command' to override

n The error message and fix is for re-running the command using the CLI.

To solve this via your personal ~/.config/nix/nix.conf file, you can add this line:

extra-experimental-features = nix-command

Note that in the config file, you do not need the prefix dashes and you need to add an '=' sign. Also, there must be whitespace before and after the equals sign.

In this example, I needed to add both 'nix-command' and 'flakes' to my nix.config file which can be done over multiple lines:

extra-experimental-features = nix-command
extra-experimental-features = flakes

or combined with two or more entries, space separated, on the right hand side of the assignment as user @NobbZ said above. However, they cannot be in quotes in the config file. The following also worked for me.

extra-experimental-features = nix-command flakes