MicroVM integration

This module wraps around microvm.nix to easily populate common microvm options on both host and guest.

To get started with microvm.nix some configuration is normally required on the host running the VMs; particularly for networking.

Host configuration

The following host configuration adds a bridge called microvm which attachs vm* tap devices to the bridge.

Module Options Reference for provision.virt.microvm.host

provision.virt.microvm.host = {
  enable = true;
  network = {
    nat.enable = true;
    basic = {
      enable = true;
      # name = "microvm"; # change bridge name
      # ipv4Subnet = "10.213.0.1/24"; # change internal IPv4 range
      # ipv6Prefix = "fd12:3456:789a::"; # change internal IPv6 range
    };
  };
};

Guest Configuration

There are more options provided for configuring the guest side of the microvms. Many options are mirrored from microvm’s options and are passed through to microvm, if set.

Module Options Reference for provision.virt.microvm.guest

Basic

The following options are core / basic options that you would set for every microvm:

microvm.guest.enable = true;
provision.virt.microvm.guest = {
  enable = true;
  # machineid = "deadbeaf"; # optionally set machine-id of guest
  vcpu = 2;
  mem = 1000;
  hypervisor = "cloud-hypervisor";
};

Network

Add a single basic interface to guest VM. The n field must be unique per microvm on host if you want to attach to the default host microvm bridge.

This is a bit unideal, future solutions will be provided.

provision.virt.microvm.guest = {
  network.base = {
    enable = true;
    # n = 1;
  };
};

Volumes and Shares

A unified option is provided to configure both microvm.shares and microvm.volumes under mounts.

provision.virt.microvm.guest = {
  mounts.cni = {
    enable = true;
    mountpoint = "/var/lib/cni"; # mountpoint in guest
    volume.size = 1000; # by default, a mount is a volume
  };
  mounts.persist = {
    enable = true;
    mountpoint = "/persist";
    share.enable = true; # use as a share
    # share.proto = "9p"; # change share protocol, default: `virtiofs`
  };
};

Nix Store

You may want to share your host nix store to reduce the image size of the microvm. If you want to use nix within the VM, you can enable the writableStoreOverlay.

provision.virt.microvm.guest.store.readonly.enable = true;

provision.virt.microvm.guest = {
  store.readwrite = {
    enable = true;
    size = 5000; # 5 GB writable nix store within guest VM
  };
};

ToDo

Add impermanence integration
Reduce default enabled shared in guest module (move to profiles)

provision-nix Documentation