Whole machines on the servers you already pay for.

Name it, pick the distribution, say how big. Lens downloads that image once from the distribution itself and keeps it beside the pool, copies it for this guest, grows the copy to the size you asked, writes the cloud-init that configures it on first boot, and defines it. The next guest from the same image is seconds rather than minutes.

The form does the arithmetic you would otherwise do in your head: how many cores and how much memory this host actually has, how much is free right now, and what this image needs as a minimum. It asks for the login to create with sudo, an SSH key to install, and — this is the detail that saves an afternoon — a password for the serial console, because a cloud image ships without one and a console that shows a prompt nothing can answer is a machine you cannot get into. That password goes into the guest's cloud-init and the file is deleted the moment it has been handed over.

The job runs on the box on its own, so closing Lens does not stop it, and it says so on the panel: keep working, it goes on.

Windows, FreeBSD, an appliance, an old distribution — anything that arrives as an ISO. Download one into the pool from the form or drop it there with the Files tab. Naming the operating system lets libvirt pick the right devices for it, and the form says which names it knows; Windows 11 gets UEFI firmware with one tick.

Then the part that makes this usable on a server in a data centre: the guest's screen is VNC, bound to the host's own loopback and never to the outside. The Screen button opens a tunnel from your computer to it, so you click through the installer from your desk with nothing exposed on the internet. No VNC port open, no password to leak, no forgotten listener left behind afterwards.

Start, shut down, back up, copy, rename. Then the things you actually come back for, each said in the words that matter rather than in libvirt's:

What it is given. A running guest can be given up to the ceiling it started with; raising the ceiling is always at its next boot. So the page shows both — in use, and at next boot — instead of pretending a change took effect when it did not.

Disks, as what the guest sees and what they actually take on the host, which are not the same number for a thin-provisioned image. Add one, grow one. Interfaces, with the note that an address appears once the guest has booted and taken its lease. Add a card, put it on another network.

Reachable from outside. A guest on NAT can get out; nothing gets in until a port of the host is pointed at it. Publishing one is three things at once, which is why it is a button and not a paragraph of documentation: Lens pins the guest's address first so the forward cannot rot after a reboot, writes libvirt's hook so it survives one, and opens the firewall. Snapshots taken while it is off, the disk alone — and the line that is simply true: a snapshot before an upgrade is the cheapest insurance there is.

Storage pools are where a guest's disk is made, so the page says the thing that actually bites: a pool that is full is a guest that cannot be created. Each with its path and its free space.

Networks in one sentence: NAT gives a guest a private address and a way out; a bridge puts it on the real network with an address of its own. A libvirt NAT network touches nothing on the host and can be made and stopped freely.

A bridge is different, and Lens refuses to be casual about it. It rewrites the server's own networking — the interface's address moves to the bridge — and it is the one change on this screen that can cut the very connection Lens is using. So the server arms a revert before anything is touched and puts everything back by itself if Lens cannot prove it is still there afterwards. The form takes the address from the interface exactly as it is now, which is what keeps the session alive across the change, and says why leaving it on both is how a box ends up answering on neither. It also tells you which tool the box uses to configure networking, because that is the file it is about to rewrite.