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Creating Virtual Machines Inside DaDesktop with Virt Manager

Introduction

When planning a course, it can be handy to spin up a virtual server inside DaDesktop, and possibly a couple of client machines as well, whether using a single OS or a mix of Windows and Linux.

You can run Nested VMs using either Virt Manager or VirtualBox—combining VirtualBox with Vagrant if you're on Linux, or VirtualBox alone if your DaDesktop runs Windows 10.

DD Machines Nested Virt

After thorough testing, we recommend Virt Manager as the better choice, since VirtualBox has a few known bugs that make it less ideal for this setup; for now, we advise against using VirtualBox in this way.

VirtManager leverages the libvirt library to offer virtual machine management. Its desktop GUI lets you create, delete, and oversee multiple VMs. While it’s mainly built for KVM virtual machines, it also works with other hypervisors like Xen and LXC.

Virt Manager integrates smoothly with Vagrant—just run: 

apt install vagrant-libvirt

Keep in mind that fewer Vagrant boxes are packaged for libvirt/kvm than for VirtualBox, but you can easily convert them for libvirt, as explained here:

https://medium.com/@gamunu/use-vagrant-with-libvirt-unsupported-boxes-12e719d71e8e
 

The interface provides an overview of all VMs, including their status, CPU usage, a live performance graph for running machines, and resource utilisation stats.

If you're new to Virt Manager, you'll find it quite like VirtualBox, though with some key differences explained below.

For a solid walkthrough on using virt‑manager on Ubuntu Linux, check out this guide: https://www.debugpoint.com/virt-manager/

 

Why use Virt Manager over VirtualBox?

Advantages
  1. Performance is significantly better – Virt Manager employs VirtIO drivers for storage, networking, and graphics, resulting in far superior speed. virtio drivers are KVM’s paravirtualized device drivers, and they’re available for both Linux and Windows guests on KVM hosts. The virtio package handles block devices (storage), network interfaces, and graphics. Since these drivers are open source, they’re simple to install if your Linux distribution doesn’t already include them.
  2. A wider range of configuration choices
  3. Pairs nicely with Vagrant
  4. Certain components of VirtualBox aren’t fully open source
  5. Virt Manager doesn’t require kernel module recompiles after a kernel upgrade, unlike VirtualBox.
  6. VirtualBox occasionally breaks when a kernel upgrade is needed.
Disadvantages
  1. It might be argued that VirtualBox has a shallower learning curve.
  2. Configuring 'Host networking' (as opposed to NAT) is easier with VirtualBox; that said, NAT covers most networking needs easily on both platforms.
  3. VirtualBox runs on many operating systems, while Virt Manager is Linux-only.


Overall, for hosting servers inside a DaDesktop machine, we lean towards Virt Manager.

 

Installation

Since libvirt is constantly evolving, stick with the latest non‑LTS Ubuntu or Debian release.

Here’s a quick overview of installing KVM and virt‑manager, but for your specific DaDesktop OS, do follow a current guide. One good resource: https://www.debugpoint.com/virt-manager/ 

sudo apt install virt-manager

sudo adduser student libvirt
sudo systemctl restart libvirtd

Restart the DaDesktop machine, then launch Virt Manager from the Applications menu.

 

Configuration

  1. Importing or converting virtual machines – it’s straightforward to build VMs from scratch to match your OS and specs, but for more complex setups you may want to import an existing server or appliance image. Many are supplied as VMDK files, which Virt Manager can sometimes add directly, though not always clearly in the current version. VirtualBox images can’t be directly imported into Virt Manager, but they can be exported to an open format like OVF, which Virt Manager handles smoothly. Alternatives include VMware Converter (if available) or Virt‑V2V (see https://www.redhat.com/en/blog/importing-vms-kvm-virt-v2v). Qemu‑convert is another excellent open‑source tool for converting between virtual machine formats.
    To convert VirtualBox VMs to the KVM format follow this guide: https://ostechnix.com/how-to-migrate-virtualbox-vms-into-kvm-vms-in-linux/

  2. Recently, a feature was added to effortlessly upload files from your local machine into your DaDesktop environment.

    If that doesn’t suit, you can fall back on cloud storage services like Google Drive or Microsoft 365, and then log into them from within DaDesktop.

  3. When importing VMs from other formats, you’ll often need to switch the graphics or disk driver type. Virt Manager shines here because of its excellent VirtIO driver support. These fully virtualised, open‑source drivers offer far better performance than native disk, network, or graphics drivers and are available for almost every OS—including strong support for Windows 10 guests. If your guest supports them, VirtIO drivers are usually the top choice for compatibility and speed under Virt Manager (KVM). https://wiki.archlinux.org/title/Libvirt
  4. Optimal VM settings for Virt Manager — VirtIO drivers are built into nearly all modern open‑source server OSes and are simple to install on Windows. While virtio is generally your best bet, other driver types might be needed in edge cases. For networking, NAT satisfies most use cases; only complex setups demand bridged host networking, which can be trickier to configure.
    A handy introductory reference is https://wiki.manjaro.org/index.php?title=Virt-manager
    Running Windows takes a few extra steps: you’ll need to slipstream the VirtIO drivers so the Windows 10 ISO can boot.
    As for disk formats, .raw files deliver the fastest speeds unless you need snapshots—then qcow2 format is better, albeit a touch slower.
  5. Even though Wayland handles display management well in many scenarios, we still recommend sticking with X11 for the time being. Still, it might be worth experimenting with Wayland in your own setup, as distributions are steadily improving Wayland support.
  6. Skip KSM—it does work in nested setups and with Virt Manager, but it makes practically no difference in real‑world usage.
  7. Tech Support is on hand if you need help converting disk images for Virt Manager or setting up Virt Manager for your DaDesktop courses.

  8. So where do disk image files live on the filesystem? By default, Virt Manager stores them in the following location, though you can configure an alternative path if you prefer: 

    /var/lib/libvirt/images