nixos-config/pkgs/firecracker-vm/default.nix

{ callPackage
, firecracker
, writeShellApplication
, writeText
}:

let
  kernel = callPackage ./kernel.nix { };
  rootfs = callPackage ./rootfs.nix { };

  vmconfig = writeText "vmconfig.json" (builtins.toJSON {
    boot-source = {
      kernel_image_path = "${kernel}/vmlinux";
      boot_args = "panic=1 console=ttyS0 ro";
    };
    drives = [
      {
        drive_id = "rootfs";
        path_on_host = rootfs;
        is_root_device = true;
        is_read_only = true;
      }
    ];
    machine-config.vcpu_count = 2;
    machine-config.mem_size_mib = 1024;
    network-interfaces = [ ];
  });

in
writeShellApplication {
  name = "firecracker-vm";
  text = "${firecracker}/bin/firecracker --no-api --config-file ${vmconfig}";
  derivationArgs.passthru = { inherit kernel rootfs; };
}