Remove IFD from cluster.nix

[rcouto]

Hello and thanks for this great project!

I noticed a considerable slowdown on the evaluation time of my flake after importing proxmox-nixos, and realized it is triggering the package building of the default proxmox-ve. I observed that by running with --option allow-import-from-derivation false , the IFD culprit is cluster.nix in the line below

https://github.com/SaumonNet/proxmox-nixos/blob/main/modules/proxmox-ve/cluster.nix#L36

Is there any chance of adjusting this module so that IFD is not triggered? Thanks!

Output of my nix eval without IFD:

error:
       … while evaluating the attribute 'optionalValue.value'
         at /nix/store/hv1dx0bah4m1mw2asfrg29wl17by9ngd-source/lib/modules.nix:1256:5:
         1255|
         1256|     optionalValue = if isDefined then { value = mergedValue; } else { };
             |     ^
         1257|   };

       … while evaluating a branch condition
         at /nix/store/hv1dx0bah4m1mw2asfrg29wl17by9ngd-source/lib/modules.nix:1256:21:
         1255|
         1256|     optionalValue = if isDefined then { value = mergedValue; } else { };
             |                     ^
         1257|   };

       … while evaluating definitions from `/nix/store/r3i0h1671yjfr8xzldmvbyffyrmx2y0m-source/modules/transposition.nix':

       … while evaluating definitions from `/nix/store/q0l2dxn7krwf4zz3b7zyh1fmnajpjc12-source/modules/checks/nixosconfigurations.nix, via option perSystem':

       … while evaluating the option `system.build.toplevel':

       … while evaluating definitions from `/nix/store/hv1dx0bah4m1mw2asfrg29wl17by9ngd-source/nixos/modules/system/activation/top-level.nix':

       … while evaluating the option `warnings':

       … while evaluating definitions from `/nix/store/hv1dx0bah4m1mw2asfrg29wl17by9ngd-source/nixos/modules/system/boot/systemd.nix':

       … while evaluating the option `systemd.services.pve-cluster.serviceConfig':

       … while evaluating definitions from `/nix/store/8w0rzdi9lcim89lzkmwl2b80bwgh1ckk-source/modules/proxmox-ve/cluster.nix':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: cannot build '/nix/store/9s4n86ickbmb14v5chadacb8wlaglcaz-pve-qemu-839b53b.drv^out' during evaluation because the option 'allow-import-from-derivation' is disabled

PS: IFD (Import from derivation) documentation - https://nix.dev/manual/nix/2.26/language/import-from-derivation