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Setting up virtual machines in DaDesktop via Virt Manager

Introduction

When you're putting together a training course, it’s often practical to run a virtualized server inside DaDesktop, and maybe a couple of client machines as well, using either the same operating system or a mix of Windows and Linux.

You can run Nested VMs through Virt Manager, or with VirtualBox (optionally combined with Vagrant) if you're on Linux, or simply VirtualBox when DaDesktop is running Windows 10.

DD Machines Nested Virt

After thorough testing, we recommend going with Virt Manager because VirtualBox presents a handful of bugs. For the time being, we don't advise using VirtualBox for this purpose.

VirtManager taps into the libvirt library to deliver VM management features. Its graphical interface lets you create, remove, and oversee several virtual machines. While it’s mainly geared towards KVM-based VMs, it can handle other hypervisors too, including Xen and LXC.

Virt Manager pairs nicely with Vagrant, — all it takes is a quick command:          

apt install vagrant-libvirt

Keep in mind that there are fewer Vagrant boxes out‑of‑the‑box for libvirt/KVM than for VirtualBox, but you can effortlessly convert them to suit libvirt, as demonstrated here :-

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

The interface gives a quick overview of all your VMs, showing their state, CPU usage, a live performance chart for running machines, and resource consumption numbers.

If you're new to Virt Manager, it feels a lot like VirtualBox but brings a handful of key distinctions, explained below.

For a thorough guide to virt-manager on Ubuntu, have a look at: https://www.debugpoint.com/virt-manager/

 

Why choose Virt Manager over VirtualBox?

Advantages
  1. Significantly better performance: Virt Manager leverages VirtIO drivers for storage, networking, and graphics, giving you a much snappier experience. Virtio drivers are KVM’s paravirtualized device drivers for both Linux and Windows guest VMs. They cover block storage, network controllers, and graphics. Being open source, they're easy to install if your Linux distribution doesn’t already include them.
  2. A wider range of configuration options
  3. Plays nicely with Vagrant
  4. VirtualBox includes some proprietary components
  5. Unlike VirtualBox, Virt Manager doesn't demand module recompiles each time there's a kernel update.
  6. VirtualBox can occasionally break after a kernel upgrade.
Disadvantages
  1. VirtualBox might have a gentler learning curve
  2. Setting up host networking instead of NAT is simpler in VirtualBox, though NAT comfortably handles most networking needs on both platforms.
  3. VirtualBox runs on multiple platforms, while Virt Manager is Linux‑only


Ultimately, for hosting servers inside a DaDesktop environment, we lean towards Virt Manager.

 

Installation

Since libvirt is constantly improving, it's best to stick with the newest non‑LTS release of Ubuntu or Debian.

To install KVM and virt‑manager, here are some quick pointers; however, we recommend following a current, detailed guide for your chosen DaDesktop OS. One such resource is this helpful walkthrough. 

sudo apt install virt-manager

sudo adduser student libvirt
sudo systemctl restart libvirtd

After rebooting the DaDesktop machine, launch Virt Manager from the Applications menu.

 

Configuration

  1. How do I import or convert virtual machines ? Although you can quickly spin up VMs tailored to your OS and specs, for more intricate configurations it’s often easier to import an existing virtual appliance or a pre‑configured server. These often come as VMDK images, which can be added straight into Virt Manager, though it might not be immediately obvious that this works with the current version. VirtualBox server images can’t be imported directly, but they can be exported to other formats like Open Virtualization Format (.OVF), which Virt Manager handles smoothly. Alternatively, if you have VMware Converter, or the virt‑v2v tool (see here), you can use that. Another excellent open‑source option is qemu‑convert, which easily converts between various virtual disk formats.
    To Convert from VirtualBox to Virt Manager KVM format follow these instructions: https://ostechnix.com/how-to-migrate-virtualbox-vms-into-kvm-vms-in-linux/

  2. Best way to import large files inside standalone. Recently, a method to conveniently upload files to your DaDesktop machine has been introduced.

    Alternatively, you can use a cloud storage service like Google Drive or Microsoft 365 and then sign in inside the DaDesktop session to grab your files.

  3. When importing other virtual machines especially from other formats, often you will need to change graphics and / or disk types. One of Virt Manager’s strongest suits is its superb support for VirtIO drivers — open‑source, fully virtualized drivers that dramatically outperform the default disk, network, or graphics drivers. They’re available for nearly every operating system, including excellent Windows 10 guest support. If your guest OS is compatible, using these drivers is almost always the top choice for performance and reliability under KVM. Check the Arch Linux wiki for details: https://wiki.archlinux.org/title/Libvirt
  4. Optimal settings for virtual machines using Virt Manager VirtIO drivers are built into most open‑source server OSes these days and can be added to Windows without much hassle. Usually they’re the best pick, although in certain situations one of the many other driver types might be needed. NAT is sufficient for most networking requirements; only when you need a more advanced setup will you consider bridged host networking, which can be trickier to get working. A great beginner‑friendly resource is https://wiki.manjaro.org/index.php?title=Virt-manager. Running Windows involves extra steps: you’ll need to slipstream VirtIO drivers into the Windows 10 ISO to get it booting. As for disk image format, raw files are fastest unless you need snapshots; if you do, go with qcow2, though it’s somewhat slower.
  5. While Wayland works well enough in many scenarios, we still suggest sticking with X11 for the moment. That said, feel free to experiment with Wayland on your own setup — distributions are steadily improving its support.
  6. You can skip KSM; even though it functions nested and within Virt Manager, it doesn’t noticeably boost performance.
  7. Tech Support is on hand if you need help converting disk images for Virt Manager or setting it up for a DaDesktop course.

  8. Wondering where the disk images live? By default, Virt Manager stores its image files in: 

    /var/lib/libvirt/images