nixos-build-vms 8 NixOS nixos-build-vms build a network of virtual machines from a network of NixOS configurations nixos-deploy-network --use-backdoor --show-trace --no-out-link --help network.nix This command builds a network of QEMU-KVM virtual machines of a Nix expression specifying a network of NixOS machines. The virtual network can be started by executing the bin/run-vms shell script that is generated by this command. By default, a result symlink is produced that points to the generated virtual network. This command also provides the --use-backdoor option, which spawns UNIX domain sockets in the current working directory by using the socat command. This allows users to remotely script a generated virtual machine. A network Nix expression has the following structure: { test1 = {pkgs, config, ...}: { services.openssh.enable = true; nixpkgs.system = "i686-linux"; deployment.hostname = "test1.example.net"; # Other NixOS options }; test2 = {pkgs, config, ...}: { services.openssh.enable = true; services.httpd.enable = true; environment.systemPackages = [ pkgs.lynx ]; nixpkgs.system = "x86_64-linux"; deployment.hostname = "test2.example.net"; # Other NixOS options }; } Each attribute in the expression represents a machine in the network (e.g. test1 and test2) referring to a function defining a NixOS configuration. In each NixOS configuration, two attributes have a special meaning. The deployment.hostname specifies the hostname of the system which is used by ssh to perform remote deployment operations. The nixpkgs.system attribute can be used to specify an architecture for the target machine, such as i686-linux which builds a 32-bit NixOS configuration. Omitting this property will build the configuration for the same architecture as the host system. This command accepts the following options: --use-backdoor Indicates that the backdoor must be enabled so that the VMs can be accessed through a UNIX domain socket. The UNIX domain sockets are created in the current working directory. --show-trace Shows a trace of the output. --no-out-link Do not create a 'result' symlink. -h, --help Shows the usage of this command to the user. NIXOS Path to the NixOS source tree. Defaults to /etc/nixos/nixos. NIXPKGS_ALL Path to the Nixpkgs source tree. Defaults to /etc/nixos/nixpkgs.