[Nix-dev] nested child configurations - was: multiple full systemprofiles

[Mathijs Kwik]

On Thu, Feb 9, 2012 at 5:45 AM, Michael Raskin <7c6f434c at mail.ru> wrote:
>>What I would like:
>>- Give child-profiles some link back to their parent. If a real link
>>would give cyclic dependency issues, a text file with just the store
>>path is probably enough too.
>
> Unfortunately, this still means circular dependency. Store paths
> mentioned inside store elements always mean dependencies, and if you can
> go from a pth to itself via such mentions, you have found a dependency
> loop.
>
> What you should consider is using /nix/var/nix/profiles/system-*-link
>
> If I remember correctly, it is not affected by switches.

Cool, indeed, that's a better entry point than /var/nix/current-system.
I can low list and switch child profiles easily.

>
> While you are at that, I was always too lazy to add all children of
> top-3 (top n with n being parameter?) configurations in GRUB menu. If
> your use case would be helped by this idea, actually changing the script
> should be easy.

The current grub behavior is ok. I rarely boot into previous
configurations, only if I screw something up.
In that case, booting the default lean base profile is fine.
So just the most recent child entries suffice.

>
>
>>I can then just use helper scripts to list all available child-configs
>>(from the top-level configuration) and switch to them.
>>- Have "nixos-rebuild boot" print the path to the config it just built
>>Then I can switch to the new config's child variant myself, performing
>>a child-to-child jump.
>
> That can be done via
>
> nixos-rebuild pull && nix-build /etc/nixos/nixos -A system --no-out-link

That works. That doesn't update grub yet, so I need to
"switch-to-config boot" in the result directory, then switch-to-config
switch on its child.
So I guess that suffices for my goal.


Thanks,
Mathijs

>
>
>