21.05 nixos-install process does not work with environment.systemPackages

[samuela]

Describe the bug
https://github.com/samuela/nixos-up is a simple, completely automated install process for NixOS. The process works wonderfully with the 20.09 installer ISO, but something in the 21.05 ISO has broken it as reported here (samuela/nixos-up#9). I've also been able to reproduce the issue.

I've consulted the NixOS manual, and the installation instructions do not seem to have changed between versions, which suggests to me that this is a regression.

To Reproduce
Either via nixos-up:

1. Set up a new virtual machine (both VMWare Fusion and VirtualBox are confirmed to have the issue)
2. Insert the 21.05 minimal installer ISO into the virtual CD drive.
3. Boot into the installer.
4. Run sudo nix-shell https://github.com/samuela/nixos-up/archive/main.tar.gz.
5. Note that the nixos-install step fails.

Alternatively,

1. Create GPT partition table: parted /dev/XXX -- mklabel gpt
2. Create boot partition with first 512MiB: parted /dev/XXX -- mkpart ESP fat32 1MiB 512MiB
3. Set the partition as bootable: parted /dev/XXX -- set 1 esp on
4. Create root partition after the boot partition: parted /dev/XXX -- mkpart primary 512MiB 100%
5. Format boot partition: mkfs.fat -F 32 -n boot /dev/XXX1
6. Format root partition: mkfs.ext4 -L nixos /dev/XXX2
7. mount /dev/disk/by-label/nixos /mnt
8. mkdir -p /mnt/boot
9. mount /dev/disk/by-label/boot /mnt/boot
10. nixos-generate-config --root /mnt
11. nixos-install --no-root-passwd

Expected behavior
The install to be successful.

Screenshots
https://user-images.githubusercontent.com/10327/120901852-14673e00-c5f2-11eb-845f-2ad18ec268ef.png

Additional context
Add any other context about the problem here.

Notify maintainers

Metadata
Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute:
# a list of nixos modules affected by the problem
module:

[samuela]

Update: I've narrowed it down to the following line of /mnt/etc/nixos/configuration.nix:

environment.systemPackages = with pkgs; [ home-manager ];

Without this one line everything builds fine, with it nixos-install fails. But this seems like an entirely innocuous setting. Why would this brick the build?

[mudrii]

I am not 100% sure but before running nixos-install try to refresh channel nix-channel --update

[samuela]

Unfortunately that doesn't make a difference for me. I ran nix-channel --update and sudo nix-channel --update, but nixos-install is still failing in the same way.

[samuela]

Oddly enough, nix-env -iA nixos.home-manager runs without issue when booting from the ISO.

[gcv]

Home-manager breaks when installed in any way other than with its own dedicated channel. I just ran into this problem: nix-community/home-manager#1267

Could it be related?

[samuela]

Interesting, I'm not sure if that's related but it is at least another data point to suggest that nixos-up should install home-manager some other way. I'm a bit concerned that home-manger is pushing so many people towards the channel installation. My understanding is that channels are known to be suboptimal and are on the way out. I wish it wasn't the recommended home-manager installation method.

[samuela]

Possible dup of #126141.

[gcv]

Possibly-related Discourse link: https://discourse.nixos.org/t/21-05-not-installing/13547

[stale]

I marked this as stale due to inactivity. → More info

[Artturin]

nix has been updated for a long time