Show HN: Virby, a vfkit-based Linux builder for Nix-Darwin

Summary

Virby - Linux Builder for Nix-darwin Virby is a module for nix-darwin that configures a lightweight, vfkit-based linux VM as a remote build machine for nix, allowing linux packages to be built on macOS. This project is modeled after nix-rosetta-builder, which provides a similar service, using lima to manage the VM. Some parts of the code in this repository are directly borrowed and adapted from that project. Quick Start Add to your flake and enable: # flake.nix { inputs . virby = { url = "github:quinneden/virby-nix-darwin" ; inputs . nixpkgs . follows = "nixpkgs" ; } ; outputs = { virby , ... } : { darwinConfigurations . "myHost" = { modules = [ virby . darwinModules . default ] ; } ; } ; } # configuration.nix services . virby = { enable = true ; cores = 8 ; memory = "6GiB" ; diskSize = "100GiB" ; } ; Then rebuild: darwin-rebuild switch --flake .#myHost Key Features On-demand activation - VM starts only when builds are needed, shuts down after inactivity - VM starts only when builds are needed, shuts down after inactivity Rosetta support - Build x86_64-linux packages on Apple Silicon using Rosetta translation - Build x86_64-linux packages on Apple Silicon using Rosetta translation Secure by default - Host-only access via loopback (i.e. 127.0.0.1 ), with automatic ED25519 key generation - Host-only access via loopback (i.e. ), with automatic ED25519 key generation Fully configurable - Adjust VM resources and add custom NixOS modules Configuration Basic Settings Option Type Default Description enable bool false Enable the service cores int 8 CPU cores allocated to VM memory int/string 6144 Memory in MiB or string format (e.g. "6GiB") diskSize string "100GiB" VM disk size port int 31222 SSH port for VM access speedFactor int 1 Speed factor for Nix build machine Advanced Settings On-Demand Activation services . virby . onDemand = { enable = true ; ttl = 180 ; # Idle timeout in minutes } ; Rosetta Support (Apple Silicon only) services . virby . rosetta . enable = true ; ...