TAKE FULL ADVANTAGE OF SNAPSHOTS

Virtualbox, QEMU and any other virtualisation tool you can name enable you to snapshot and restore VMS with the click of a button or a flourish of the command line. These are great because you can easily roll back the system to a known-good state.

XCP-NG takes things even further: you can create long trees of snapshots all stored with remarkable efficiency.

It can be frustrating when you find yourself regularly provisioning new virtual machines, installing virtual operating systems and getting them all updated before you can achieve your virtual goals. Indeed, this is part of the reasons why containers (see over the page) are popular. But snapshots can help here, too. The idea is simple, before you start sullying your nice clean operating system with huge applications, PPAS or random scripts, just get everything updated and rebooted and take a snapshot. Then clone this snapshot as a new virtual machine, and do what you will with the previous VM.

Tend to the clean VM as regularly as your schedule allows, then whenever you require a new VM, just clone it again. Hey presto, your favourite distro, virtualised on demand. Naturally, if this image is to be the progenitor of many a VM then it’s worth ensuring the thing is set up correctly. It might take a little experimentation to see, for example, if Virtio graphics are better than the QXL video device.

Virt-manager makes it straightforward to snapshot (and undo your ill-thought-out modifications, too).