That's expected by `build-remote` and makes sure that errors are
correctly forwarded to the user. For instance, let's say that the
host-key of `example.org` is unknown and
nix-build ../nixpkgs -A hello -j0 --builders 'ssh-ng://example.org'
is issued, then you get the following output:
cannot build on 'ssh-ng://example.org?&': error: failed to start SSH connection to 'example.org'
Failed to find a machine for remote build!
derivation: yh46gakxq3kchrbihwxvpn5bmadcw90b-hello-2.12.1.drv
required (system, features): (x86_64-linux, [])
2 available machines:
[...]
The relevant information (`Host key verification failed`) ends up in the
daemon's log, but that's not very obvious considering that the daemon
isn't very chatty normally.
This can be fixed - the same way as its done for legacy-ssh - by passing
fd 4 to the SSH wrapper. Now you'd get the following error:
cannot build on 'ssh-ng://example.org': error: failed to start SSH connection to 'example.org': Host key verification failed.
Failed to find a machine for remote build!
[...]
...and now it's clear what's wrong.
Please note that this is won't end up in the derivation's log.
For previous discussion about this change see
https://github.com/NixOS/nix/pull/7659.
Change-Id: I5790856dbf58e53ea3e63238b015ea06c347cf92
without these changes the tests will very repeatably (although not very
reliably) wedge in our runs. the ssh command starts, opens a sessions,
does something, the session closes again, but the test does not move on.
adding *just* the redirect and not the unit waits is not sufficient
either, it needs both. this feels like a bug in the nixos testing
framework somewhere, but digging that far is not in the cards right now.
Change-Id: Idab577b83a36cc4899bb5ffbb3d9adc04e83e51c
Include phase reporting in log file for ssh-ng builds
(cherry picked from commit b1e7d7cad625095656fff05ac4aedeb12135110a)
Change-Id: I4076669b0ba160412f7c628ca9113f9abbc8c303
Maximilian Bosch
eldritch horrors