Nix: how to correctly install Nix on ArchLinux

[k2s]

situation:

• clean ArchLinux installation
• installation of Nix from AUR package https://aur.archlinux.org/cgit/aur.git/tree/PKGBUILD?h=nix

./configure --prefix=/usr \
              --libexecdir="/usr/lib/$pkgname" \
              --sysconfdir=/etc \
              --enable-gc
make
make install

• replacing /etc/profile.d/nix.sh with current version provided in pull request #452
• intentionally NOT installing https://aur.archlinux.org/packages/nix-multiuser
• no /etc/nix/nix.conf file

expected:

• out of box working Nix (nix-env, nix-channel, etc.) under root account
• not usable Nix under user accounts

current result:

• logging in as root first time will initialize Nix for root
• but running nix-env will print error message:

warning: the group ‘nixbld’ specified in ‘build-users-group’ does not exist
building path(s) ‘/nix/store/n2i7g8pmylm2wbxz2hl1fvyfz3ay7vcp-user-environment’
error: the group ‘nixbld’ specified in ‘build-users-group’ does not exist

• logging in as regular user will always print messages:

mkdir: cannot create directory ‘/nix/var/nix/profiles/per-user/k2s’: Permission denied
stat: cannot stat '/nix/var/nix/profiles/per-user/k2s': No such file or directory
Nix: WARNING: bad ownership on /nix/var/nix/profiles/per-user/k2s, should be 1000
mkdir: cannot create directory ‘/nix/var/nix/gcroots/per-user/k2s’: Permission denied
stat: cannot stat '/nix/var/nix/gcroots/per-user/k2s': No such file or directory
Nix: WARNING: bad ownership on /nix/var/nix/gcroots/per-user/k2s, should be 1000
/usr/lib/prezto/modules/fasd/init.zsh:32: permission denied: /usr/lib/prezto/modules/fasd/cache.zsh

I would like to fix Nix installation on ArchLinux, but need to understand:

1. should latest version of Nix be installed always with multiuser in mind ?
2. build-users-group=nixbld seams to be now default setting (had to be added manually before), should it be somehow cleared in /etc/nix/nix.conf or should it be always created in OS package ?
3. Nix install will not chmod 1777 /nix/var/nix/{profiles,gcroots}/per-user. Should ArchLinux package always apply this or should nix-profile.sh.in be changed to handle such situation (handle non-multiuser setup) ?

[wmertens]

Looks like nix is assuming things about nixbld when running as root?

Not sure how to fix atm…

[k2s]

1. reading edolstra reaction tells me, that Nix installation should support booth, single and multi, user setup
2. If Nix relays now on nixbld group, I will create it in ArchLinux package. But would like to get some "authoritative" answer from Nix development team
3. same issue was discovered by test so I would propose that @wmertens script should test if /nix/var/nix/{profiles,gcroots}/per-user was made writable

[wmertens]

I think it would be a good idea to provide the nixbld group. The script doesn't need to test if that dir is writeable, in normal operation you simply get an error message, nothing more.

[roper79]

Any progress here, please?

[domenkozar]

cc @edolstra, this one is very unpleasant.

[chrissound]

Yeah not too sure if I'm encountering the same problem but:

 ✘ chris@archamd  ~  nix-env -q
error: creating directory ‘/nix’: Permission denied
 ✘ chris@archamd  ~  sudo nix-env -q
warning: the group ‘nixbld’ specified in ‘build-users-group’ does not exist
 chris@archamd  ~  group
 ✘ chris@archamd  ~  sudo nix-env -i                                                                                                                                                         
warning: the group ‘nixbld’ specified in ‘build-users-group’ does not exist
error: getting information about ‘/root/.nix-defexpr’: No such file or directory
 ✘ chris@archamd  ~  sudo nix-env -i vim
warning: the group ‘nixbld’ specified in ‘build-users-group’ does not exist
error: getting information about ‘/root/.nix-defexpr’: No such file or directory

[ghost]

I'm also having the same issues as @chrissound, unable to use nix on Archlinux because of this.

[chrissound]

Just tried this again and I'm still having issues:

nix-env -q        
error: Nix database directory ‘/nix/var/nix/db’ is not writable: Permission denied

sudo nix-env -q
warning: the group ‘nixbld’ specified in ‘build-users-group’ does not exist

[joachifm]

I've been using nix on arch linux for a long time. I use sysusers.d and tmpfiles.d to intialize stuff + the bootstrap tarball, works really well here ...
EDIT: that is to say, I don't know that there's really an issue with arch linux per se

[chrissound]

@joachifm what are sysusers.d and tmpfiles.d? I don't see any mention of those on http://nixos.org/nix/manual/ could you point me to any resources?

[joachifm]

@chrissound sorry, I was referring to systemd-{sysusers,tmpfiles}, a convenient method of initializing the requisite users and directory structure for nix.

[Cutuchiqueno]

@joachifm can you elaborate on the exact steps you took to get nix working with using your approach?

[joachifm]

@Cutuchiqueno I think this is a pretty good writeup https://gist.github.com/expipiplus1/e571ce88c608a1e83547c918591b149f.

[chrissound]

Just to confirm I got it working with the link provided. Thank you @joachifm

The AUR package (https://aur.archlinux.org/packages/nix/) would need to be updated to include those instructions in the PKGBUILD file. I had to mkdir /nix chown chris:chris /nix.

[mrkgnao]

@expipiplus1's instructions work for me too.

[steve-chavez]

Thanks to the pointer by kyrias, I managed to make nix work in ArchLinux with:

sudo pacman -S rsync
bash <(curl https://nixos.org/nix/install) --daemon
# After finishing the installer there's this message:
# Before Nix will work in your existing shells, you'll need to close
# them and open them again. Other than that, you should be ready to go.

# Try it! Open a new terminal, and type:

#  $ nix-shell -p nix-info --run "nix-info -m"

# But the nix commands were not added to my PATH, did a:
source /etc/profile.d/nix.sh
# and all working good now, added that to my .bashrc as well

[bew]

Fresh new user here, I did the same as @steve-chavez (https://github.com/NixOS/nix/issues/879#issuecomment-410904367), it worked well!

I guess this issue can be closed?

[joshleeb]

Want to second @bew and @steve-chavez - following the steps in #879r410904367 (on a fresh Arch install) worked perfectly!!

[masterdezign]

See also this article https://wiki.archlinux.org/index.php/Nix