Hi. It seems mainstream NixOS is heading toward using nixpkgs.lib.nixosSystem, and standard ways of defining nixos hosts in a flake.nix: https://nixos.wiki/wiki/Flakes#Using_nix_flakes_with_NixOS

Any thoughts on integrating with that world with colmena? I'm keen to keep my configuration as close to "mainstream" as I can, while using remote deploys (some of my hosts are definitely too weak to build themselves).

It seems mainstream NixOS is getting remote deploys too: nixos-rebuild --flake .#mymachine --target-host mymachine-hostname --build-host localhost switch

In reply to @n0emis:noemis.me
Is there a easy way to acces the merged nixos-config, e.g. to build a vm with it (via nixos-rebuild build-vm or something like it)?

Could we have a CLI argument or environment variable to override the deployment.targetUser? Useful in cases where the remote user isn't the same, but someone else might need to use a different username to deploy, so setting it in the Nix configuration isn't helpful.

so i use colmena exec to reboot all the machines in my hive, and it always exits with an error because it's not able to call nix(?); says it exits with an error code of 255

why would it be trying to run nix? and is it trying to do it on the remote machine which is probably down by the time it tries to run it...?

In reply to @winterqt:nixos.dev

so i use colmena exec to reboot all the machines in my hive, and it always exits with an error because it's not able to call nix(?); says it exits with an error code of 255

why would it be trying to run nix? and is it trying to do it on the remote machine which is probably down by the time it tries to run it...?

In reply to @zhaofeng:zhaofeng.li
Oh right, I should change the error message from "Nix exited with error code" to "Child process exited with error code." It's misleading in this case.

In reply to @winterqt:nixos.dev
would the child process be ssh in this case?

If you use a flake of colmena and do inputs.nixpkgs.follows = "nixpkgs";, it fails to build:

error: builder for '/nix/store/2sikwzzkkzggxi7snbml0sc7sv4wkzn2-nix-eval-jobs-0.0.1-colmena.drv' failed with exit code 1;
       last 10 log lines:
       > unpacking source archive /nix/store/wndp1lpb7g9gs3fmh4pjmqw80pjiw606-source
       > source root is source
       > patching sources
       > applying patch /nix/store/mgnkwc0sbk8x3jn4x7gny013mp4gsvfh-1e0f309fefc9b2d597f8475a74c82ce29c189152.patch
       > patching file src/nix-eval-jobs.cc
       > Hunk #2 FAILED at 37.
       > Hunk #3 succeeded at 96 with fuzz 1 (offset -7 lines).
       > Hunk #4 succeeded at 235 (offset -14 lines).
       > Hunk #5 succeeded at 288 (offset -14 lines).
       > 1 out of 5 hunks FAILED -- saving rejects to file src/nix-eval-jobs.cc.rej
       For full logs, run 'nix log /nix/store/2sikwzzkkzggxi7snbml0sc7sv4wkzn2-nix-eval-jobs-0.0.1-colmena.drv'.

In general, I like to run my systems on stable nixpkgs as much as possible.

This fixes apply-local not detecting the system as NixOS due to the changes in the format of the os-release file.

Details on the changes made to the os-release file can be found in the following commit https://github.com/NixOS/nixpkgs/commit/bae181d3f0f453d9a23cf5e899c2cb0f96e91fef.

I'm new to Rust so let me know if I've missed anything, thanks!

In reply to @winterqt:nixos.dev
unstable manual is 404ing 😕
was it moved to 0.3 (instead of unstable)?

A plan or diff-current-to-next command would be useful to have.

We can get something pretty close already by combining colmena and nix-diff:

$ colmena build --on laptop
[INFO ] Using configuration: ./deployment.nix
[INFO ] Enumerating nodes...
[INFO ] Selected 1 out of 5 hosts.
       ✅ 11s All done!
laptop ✅ 10s Evaluated laptop
laptop ✅ 1s Built "/nix/store/r829pyjngqxmn7k1j9j39w3rcaarg2d1-nixos-system-laptop-21.11pre-git"

$ nix-diff --color always --character-oriented /var/run/current-system /nix/store/r829pyjngqxmn7k1j9j39w3rcaarg2d1-nixos-system-laptop-21.11pre-git | less -R

There are a few problems with the above:

• nix-diff is a separate package to install,
• the diff isn't great (the full diff contains the entirety of options.xml and is 26MB in size); that said, i think that if we diffed just a few specific things like system-path, that would be useful,
• the diff requires the previous system derivation to be available locally.

If you're interested in a feature like this, I'd be up for rewriting nix-diff as a rust library and trying to integrate it into colmena.