mobile-nixos-cfg | A personal Mobile NixOS adventure

The original post https://nixos.wiki/wiki/Distributed_build. Here we teach the Host PC's nixos to use the Pinephone as a remote build agent. Not sure, but it seems that it works faster than host-based build using qemu which also works by default.
Determine, which user runs builds on the Host PC. In our case, since we are using build daemon of NixOS, the user is root.
Setup the passwordless SSH loging from the Host PC's root user to the pinephone. Add the root's public SSH keys to the root@pinephone (done in the example.nix) Rebuild and switch the Pinephone's configuration with sh script/build-switch-toplevel.sh Add the pinephone-builder section into the /root/.ssh/config of the Host.
Add the following snippet to the Host PC's configuration: { config, pkgs, ... }: { nix.buildMachines = [ { hostName = "pinephone-builder"; sshUser = "root"; systems = ["aarch64-linux"]; maxJobs = 1; speedFactor = 2; mandatoryFeatures = [ ]; } ] ; nix.distributedBuilds = true; }
Test the config with (host) $ sudo nix ping-store --store ssh://pinephone-builder && echo ok ok
Now the distributed aarch builder should work on the Pinephone natively. Test with (host) $ vim modules/nixpkgs/pkgs/tools/misc/mc/default.nix ... edit smth to force rebuilding (TODO: how to --check distributed build?) (host) $ sh script/build-mobile-nixos.sh -j0 -A pkgs.mc
Watch the host's log and the pinephone's htop.