[Nix-dev] nixos-rebuild without Internet

[James Cook]

On 24 June 2017 at 22:52, Maximilian Bosch <maximilian at mbosch.me> wrote:
> Hey guys,
>
> I'm using a NixOS setup on my developer machine. For WLAN networks I use the
> `networking.wireless` option as it allows me a declarative/reproducible
> setup of the networks I use on a daily basis.
>
> Unfortunately I'm facing from time to time the following issue: whenever I
> try to add a new network (and no connection is available ATM) I have a
> problem running `nixos-rebuild` as the rebuild usually causes a lot of other
> operations and some of them require a connection to the internet (e.g. for
> [re]downloads).
>
> However this is quite bad when I need a new network, but the rebuild fails.
> I currently solve it using several tricks, but in the end I'd like to now if
> there's some kind of tool to do a "partial-rebuild" on a NixOS machine
> (although it might break the reproducability as the expressions wouln'dt be
> 100%-deterministic anymore) or if I have to live with this issue.
>
> Thanks and have a nice Sunday,
>
> Maximilian

Hi Maximilian,

If you only make a configuration change like reconfiguring a network
interface, I'd expect nixos-rebuild to work without a network.

If you update your nixpkgs version (e.g. nix-channel --update or git
pull or passing --upgrade to nixos-rebuild) that could mean the next
build requires a network connection. Could that be it?

Or is it trying to access the binary cache? If so, there's surely some
way to disable that so it builds everything locally.

James