NixOS VM Cluster

This is a template for running a cluster of NixOS VMs using QEMU. This can be useful for testing distributed systems, your NixOS configurations, learning or just having fun.

This is simply a template, so I invite you to fork and modify it to your needs. To start the cluster, simply run:

$ git clone https://github.com/viperML/cluster
$ cd cluster

$ nix run -f ./default.nix run -L

default.nix configures the virtual machines, by linking together their networks. With this configuration, each machine is accesible from each other by their name, so you can simply do ping lab0 from lab1, etc.

You can also access each machine by SSH. We forward the SSH port from the VM to the host port 22220 + i, where i is the machine index (0, 1, 2, ...). The default user and password is nixos nixos, but you can add your own public key in modules/base.nix. The following command connects to lab0:

$ ssh -p 22220 -o StrictHostKeyChecking=no nixos@localhost

The QEMU machines run without any need of root privileges on the host system, using user-mode networking.

Usage as a library

$ npins init
$ npins add github viperML cluster -b main
$ tee default.nix <<EOF
let
  sources = import ./npins;
  pkgs = import sources.nixpkgs { };
in
import sources.cluster {
  inherit pkgs;
  machines = {
    lab1 = { };
    lab2 = { };
  };
}
EOF
$ nix run -f ./default.nix run -L