In reply to @cw:kernelpanic.cafe
How can I deploy to a host with no internet access (or working name resolution)? Builds fail when the remote host tries to download from the the nixos cache. I'd like to still be able to use the cache but download it from the build machine instead of target host if that's reasonable.

In reply to @zhaofeng:zhaofeng.li
--no-substitutes which will probably be renamed in the future (https://github.com/zhaofengli/colmena/issues/59)

syntaxerror ✅ 4m Activation successful

Thank you very much!

In reply to @buckley310:matrix.org
I just disable the binary caches in the configs of machines with no internet. Less typing

In reply to @winterqt:nixos.dev
So when using buildOnTarget, what decides if the drv should be built and copied on the host or built on the target? I know most do the latter, but things such as a source folder (from a flake input) have definitely gotten copied before, so...

When I run colmena build --on some-host, colmena will be stuck in the "Evaluating" step and seemingly never ends. When I run colmena build --on some-host -v (note the added -v argument), the same build continues normally and finishes within one minute.

Example output:

# Time 00:25:20 
$ colmena build --on some-host
warning: Git tree '/path/to/my/nixos-config' is dirty
[INFO ] Using flake: git+file:///path/to/my/nixos-config
[INFO ] Enumerating nodes...
warning: Git tree '/path/to/my/nixos-config' is dirty
warning: Git tree '/path/to/my/nixos-config' is dirty
warning: Git tree '/path/to/my/nixos-config' is dirty
[INFO ] Selected 1 out of 13 hosts.
                🕓 54s 1 running
# I pressed Ctrl-C after ~1min, but it will run forever if I didn't do that

# Time 00:26:19
$ colmena build --on some-host -v
warning: Git tree '/path/to/my/nixos-config' is dirty
[INFO ] Using flake: git+file:///path/to/my/nixos-config
[INFO ] Enumerating nodes...
warning: Git tree '/path/to/my/nixos-config' is dirty
warning: Git tree '/path/to/my/nixos-config' is dirty
warning: Git tree '/path/to/my/nixos-config' is dirty
[INFO ] Selected 1 out of 13 hosts.
some-host | Evaluating some-host
some-host | warning: Git tree '/path/to/my/nixos-config' is dirty
some-host | Evaluated some-host
some-host | Building some-host
some-host | /nix/store/xl1n3k4vbd8aa20kgs6nx10wyyzmbiij-nixos-system-some-host-22.05pre-git
some-host | Built "/nix/store/xl1n3k4vbd8aa20kgs6nx10wyyzmbiij-nixos-system-some-host-22.05pre-git"
          | All done!
# Time 00:26:36, the same job is done in 20 seconds

When colmena is stuck, it seems to be waiting for a defunct nix-store process:

$ ps -aux
# ...
lantian   811648  0.1  0.0 1225260 6016 pts/1    S<l+ 00:25   0:00 colmena build --on some-host
lantian   847160  0.0  0.0      0     0 pts/1    Z<+  00:25   0:00 [nix-store] <defunct>

Bisect shows this issue is introduced in https://github.com/zhaofengli/colmena/commit/26b2203da9a8a0f7913c61de3343430da66579b5.

I'm on latest nixos-unstable, and here's my nix-info report:

 - system: `"x86_64-linux"`
 - host os: `Linux 5.16.13-xanmod1-lantian, NixOS, 22.05 (Quokka)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.8.0pre20220311_d532269`
 - nixpkgs: `/etc/nix/inputs/nixpkgs`

In reply to @winterqt:nixos.dev
I wish there was a way we could parallelize the derivation copy step for buildOnTarget, this takes ages on large upgrades >.<

In reply to @zhaofeng:zhaofeng.li
I looked at it, and it appears that Nix used to be able to copy paths in parallel, but it's disabled for some reason: https://discourse.nixos.org/t/speed-up-nix-copy/15884/5

Nixops has the convenient --exclude option that allows deploying every node except the given ones. This would be nice to have in colmena as well, particularly in combination with the tags feature.