Debian developers have a habit of writing utilities for maintaining distributions that are also useful for ordinary users. For example, diffoscope [1], which compares binary files, is useful for both version control and comparing – among others – PDF and LibreOffice files. In the past year or so, an equally useful utility called debvm has emerged. As the name suggests, debvm [2] is a tool for the quick and easy creation of virtual machines (VMs) running Debian releases and architectures [3]. While debvm gives developers the ability to test releases and architectures without changing hardware, it can be also be useful to any user as a sandbox for testing scripts or checking the results of mixing repositories. Where traditional virtualization methods such as VMware, VirtualBox, or Gnome Boxes create permanent VMs, often for the purpose of running another operating system, debvm is ideal for creating VMs for specific, limited purposes with a small memory footprint.

You will find the debvm 0.2.12 package in the repository of Debian 12 (Bookworm) and the 0.2.7 package in Ubuntu 23.04 repositories. Undoubtedly, other Debian derivatives will start to carry it as it gets closer to general release, although the current releases are stable enough to be worth exploring. The packages consists of three command-line tools: debvm-create, debvm-run, and debvm-waitssh. All three commands include intelligent defaults that make the bare command usable, as well as a handful of options each.

debvm-create

As a wrapper for mmdebstrap, debvm-create lets you create a chroot jail. Used without any options, debvm-create produces a VM with the host machine's format, files from the repository debvm is taken from, and one gigabyte of memory. No password is required. Instead of user accounts, users are automatically logged in as root. Repositories and apt are installed, as well as basic utilities. Note that if you use the package from Debian Unstable, which as its name implies is constantly changing, you may sometimes be unable to install everything. However, such problems do not always make the resulting VM completely unusable. The VM is a file called rootfs.ext4 in the current working directory.

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