nixos-rebuild: Ask for admin privileges

[AMDphreak]

Issue description

nixos-rebuild should ask for elevated privileges.

citing this: VSCode does not build (declarative installation) #55790

Additionally, it appears that you've used nixos-rebuild without sudo which is probably why you got the permission error.

[matthewbauer]

I think only nixos-rebuild switch needs root priveleges.

[vcunat]

Right, I commonly build my system without root privileges with nixos-rebuild build, and then I use boot or switch with sudo. Adding --upgrade would also require sudo.

[AMDphreak]

I think only nixos-rebuild switch needs root priveleges.

Good catch. I wasn't aware. I've been doing all commands as root.

[aaronjanse]

Prompting the user for the sudo password at the beginning can save time. Think of how installing Windows would (at least used) take a while due to blocking dialogs showing up while the user is off doing another task (since the install takes a while).

On the other hand, the user may want to run as superuser only what's necessary, for security reasons. I don't know if this is a legitimate concern once the entire the nixos-rebuild process is taken into account.

[aaronjanse]

Relevant: https://discourse.nixos.org/t/error-on-nixos-rebuild-with-an-empty-configuration-file/1555

[AMDphreak]

@aaronjanse It does so much more. Requesting root is an essential user experience change. Linux land is filled with unhelpful error messages. This habit has to be fixed.

[domenkozar]

Relevant: https://github.com/hercules-ci/ghcide-nix/issues/14#issuecomment-542912692

[domenkozar]

Seems like the consensus is to improve the error message based on #57333 (comment)

[stale]

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[bobvanderlinden]

It seems there is a conscious decision to not automatically run sudo, but make it explicit.

It is possible to run sudo automatically when using --use-remote-sudo:

$ nixos-rebuild --use-remote-sudo boot

Should the user be informed about this option when they run into permission errors?

[con-f-use]

The problem with that nixos-rebuild --use-remote-sudo is broken (see #118655)

[rgri]

Curious if there are any favourite workarounds people are using for this. I suppose I will just end up using a deployment tool, but my scale is reallly small, so if I could deploy using just nixos-rebuild I'd be very happy with that.