nixos-install unstable 16.03pre69762 fails

[ghost]

installing from unstable nixos machine to /mnt; nixos-install fails:

/nix/store/ycl4b69q5k43z0cnyyl8dw4w52jid3na-stage-1-init.sh.drv
/nix/store/rhga7k8yismf8fr4acp8cra5zmgfvc4x-initrd.drv
/nix/store/ylz62ka1qap5jnvf58f4i5ynq7hbcd6g-users-groups.json.drv
/nix/store/rrg5li911g26s76k3rkcksxzypxh93k6-nixos-system-nixos-16.03pre69762.e916273.drv
these paths will be fetched (0.00 MiB download, 8.32 MiB unpacked):
/nix/store/8ignm13qyb4npb00y01yj6szj9zhhj62-libXt-1.1.5
/nix/store/azadkmfzykwb8h1y007831zwd8vbz2li-libXmu-1.1.2
/nix/store/gsc42mc0vqfpl8d078zm07jy5xva7r4w-libX11-1.6.3
/nix/store/r3xv21sfbky2pi0x8gypidal63m057f7-libxcb-1.11.1
/nix/store/r457i29jhs433sgj7dnv02a2jrf2j0qz-dbus-tools-1.8.20
/nix/store/w7rkbg3vsvbpcw6zfy5dahlrf41wp3js-xauth-1.0.9
/nix/store/wncmry3c49vgkg7y4c72s1khwzkzhggq-libXext-1.3.3
building path(s) ‘/nix/store/0r3h90h24qdb7jaqyyxd63k5fh3d1clk-users-groups.json’
while setting up the build environment: executing ‘/nix/store/xag5ayq906w9zhlxs8wayv4kvpiyqphq-bash-4.3-p42/bin/bash’: Permission denied
builder for ‘/nix/store/ylz62ka1qap5jnvf58f4i5ynq7hbcd6g-users-groups.json.drv’ failed with exit code 1
cannot build derivation ‘/nix/store/rrg5li911g26s76k3rkcksxzypxh93k6-nixos-system-nixos-16.03pre69762.e916273.drv’: 1 dependencies couldn't be built
error: build of ‘/nix/store/rrg5li911g26s76k3rkcksxzypxh93k6-nixos-system-nixos-16.03pre69762.e916273.drv’ failed

[ghost]

I can run /nix/store/xag5ayq906w9zhlxs8wayv4kvpiyqphq-bash-4.3-p42/bin/bash without problems so the rights are fine. DerivationGoal::runChild method has 378 lines so it is not clear what should I be focusing on.

[rnhmjoj]

It fails for me too on generating users-groups.json but for another reason. It says that the directory /run/users does not exist but in fact it's right there.

[elitak]

(POTENTIAL WORKAROUND)

I was running into this problem on every nix+nixpkgs version combo I tried. Sometimes it would be on a different "audit" derivation instead. The cause turned out to be that I was running nixos-install targeting a bind-mount. As soon as I switched to a loopback-mounted ext4.img, everything ran fine. I guess nixos-install has some weird mount-related internals that get broken by bind-type mounts. Another error I ran into under similar circumstances complained about something like "unshare" not working.

I really think nixos-install should support bind-mounts and even no mounts at all (just point it to an empty directory) or at least have good documentation as to why they can't be supported and give better error messages.

[elitak]

I had a lot of trouble trying to get any more details out of nixos-install trace log and gave up.

To reproduce:
Deploy a fresh ubuntu/debian vm and run basically theses steps, but instead of loopback mounting an ext4 image, just bindmount (or no mount) the target directory:
https://gist.github.com/elitak/996e3b3c54c07409c8f2

[domenkozar]

Are these errors still present?

[rnhmjoj]

It has never happened again for me but possibly mine was a different issue. I don't know about the others.

[elitak]

I tried briefly to reproduce, but failed. It's no longer blocking me anyway.

[domenkozar]

Please reopen if issue persists :)