Nix: Weird installation issue

[winks]

Just trying to install on Ubuntu 18.04. Somehow my system curl can just download the file, but then some part of the installer can't resolve the host name?

$ bash <(curl https://nixos.org/nix/install)                                                          -127-
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  2472  100  2472    0     0  10519      0 --:--:-- --:--:-- --:--:-- 10519
downloading Nix 2.1.3 binary tarball for x86_64-linux from 'https://nixos.org/releases/nix/nix-2.1.3/nix-2.1.3-x86_64-linux.tar.bz2' to '/tmp/nix-binary-tarball-unpack.WVAREBHpg0'...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 21.2M  100 21.2M    0     0  3390k      0  0:00:06  0:00:06 --:--:-- 3603k
Note: a multi-user installation is possible. See https://nixos.org/nix/manual/#sect-multi-user-installation
performing a single-user installation of Nix...
directory /nix does not exist; creating it by running 'mkdir -m 0755 /nix && chown florian /nix' using sudo
[sudo] password for florian: 
copying Nix to /nix/store................................
initialising Nix database...
Nix: creating /home/florian/.nix-profile
installing 'nix-2.1.3'
building '/nix/store/9jddl2a8j1igdq3ml4lw8m2609ri0m89-user-environment.drv'...
created 6 symlinks in user environment
warning: unable to download 'https://nixos.org/channels/nixpkgs-unstable': Couldn't resolve host name (6); retrying in 340 ms
warning: unable to download 'https://nixos.org/channels/nixpkgs-unstable': Couldn't resolve host name (6); retrying in 652 ms
warning: unable to download 'https://nixos.org/channels/nixpkgs-unstable': Couldn't resolve host name (6); retrying in 1072 ms
warning: unable to download 'https://nixos.org/channels/nixpkgs-unstable': Couldn't resolve host name (6); retrying in 2240 ms
error: unable to download 'https://nixos.org/channels/nixpkgs-unstable': Couldn't resolve host name (6)
$ host nixos.org                                                                                      -127-
nixos.org has address 54.217.220.47
nixos.org mail is handled by 10 mx00.udag.de.
nixos.org mail is handled by 20 mx01.udag.de.

[winks]

Ok, it seems to have installed just fine - the same error when running ~/.nix-profile/bin/nix-channel --update.

[edolstra]

What's the contents of your /etc/nsswitch.conf? There may be some NSS modules there that Nix's Glibc doesn't have access to.

[Zopieux]

@winks Had the same issue, Googled to find #687, solution on my distro (Arch):

$ systemctl start nscd

[winks]

@edolstra

passwd:         compat systemd
group:          compat systemd
shadow:         compat
gshadow:        files

#hosts:          files mdns4_minimal [NOTFOUND=return] resolve [!UNAVAIL=return] dns
hosts:          files resolve mdns4_minimal [NOTFOUND=return] [!UNAVAIL=return] dns
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis

And yes, putting dns before resolve works, but I don't see this as a solution, see below.

@Zopieux thanks, but I don't have nscd and I don't plan on installing it just for nixpkgs.

Also this worked on 16.04 ootb, so I do think it's not an other-OS problem per se, if one assumes that nixpkgs is supposed to work on other distros, and name resolution in general works. I can't believe this would be the only application on my machine that doesn't work without nscd.