Aeon: openSUSE for lazy developers

The openSUSE project recently announced the second release candidate (RC2) of its Aeon Desktop, formerly known as MicroOS Desktop GNOME. Aside from the new coat of naming paint, Aeon breaks ground in a few other ways by dabbling with technologies not found in other openSUSE releases. The goal for Aeon is to provide automated system updates using snapshots that can be applied atomically, removing the burden of system maintenance for "lazy developers" who want to focus on their work rather than desktop administration. System-tinkerers need not apply.

The idea behind Aeon, as with other immutable (or image-based) Linux distributions, is to provide the core of the distribution as a read-only image or filesystem that is updated atomically and can be rolled back if needed. Google's ChromeOS was the first popular Linux-based desktop operating system to follow this model. Since the release of ChromeOS a number of interesting immutable implementations have cropped up, such as Fedora Silverblue, Project Bluefin (covered here in December 2023), openSUSE's MicroOS (covered here in March 2023), and Ubuntu Core.

What makes up the core software and how the immutable bits are composed, deployed, and managed varies quite a bit between distributions. Aeon uses a utility called transactional-update (with openSUSE's Zypper package manager under the hood) and Btrfs subvolumes to create and update system snapshots. Basically, instead of installing and updating a system with individual packages while it is running, the updates are applied in the background to a separate Btrfs snapshot and then the system is rebooted into that snapshot. The /home and /var directories are, of course, writable Btrfs volumes; /etc uses overlayfs to apply local changes on top of the default configuration files.

User-installed software for these distributions is separated from the rest of the system software on a mutable filesystem using some type of application-containerization technology like Flatpak, Podman, or Snap. In Aeon's case, user applications are generally installed via Flatpak, or using a traditional package manager inside a containerized Linux distribution of the user's choice that is managed with Distrobox. (On Aeon, Distrobox uses Podman to run containers.)

Installation and updates

The openSUSE YaST team has been working on a new installer called Agama, but Aeon has its own installer, the Transactional Installation Kit (tik). The tik installer is designed to deploy operating system images to UEFI hardware, which means that users with older hardware are (at least currently) out of luck when it comes to installing Aeon. It can also make use of the Ignition and Combustion configuration tools to create users, enable services, install SSH keys, and more, automatically at install time.

As with the rest of the distribution, the philosophy for tik is "minimal". Tik does not ask the user to make any choices about software, how disk partitions should be laid out, or much else, except to confirm that the installation should proceed. Users are prompted to choose which disk to use, when a system has multiple disks. If the target system has a existing MicroOS installation, tik will offer to back up (and restore) existing users and data as long as the USB stick with the installer has more free space than the data stored in the home directory.

After installation, there is a first-run wizard to perform system configuration. It asks for the usual information: the language and keyboard layout to use, wireless network connection information, time zone, and user information. Aeon does not configure a root user, so the first system user is set up as an administrator and can use sudo to perform any administrative tasks.

Truly minimal desktop

Aeon is composed from packages in the openSUSE Tumbleweed and MicroOS repositories, so Aeon RC2 provides users with an up-to-date GNOME 46 desktop using Wayland. (GNOME 46.2, to be exact.) It also includes Linux 6.9.3, systemd v255, and glibc 2.39.

Many Linux distributions offer "minimal" desktop package selections, but openSUSE Aeon takes this farther than most. Aside from some basic applications one would expect with GNOME—such as the file manager, settings application, and other utilities—Aeon comes with almost no software installed as part of the base system. Firefox and GNOME's text editor, calculator, and terminal application are all installed as Flatpaks as a second step after the desktop user logs in the first time. If a user wants a media player, office suite, email application, or even image and PDF viewers, they have to be installed separately. That may be taking minimalism a bit too far, but it does give users a lot of control over what is installed on their system.

Aeon is touted as a distribution for users who do not want to hassle with system administration, but its sparse selection of software ensures that some up-front work is required to reach the payoff. For example, aside from having to install expected utilities like a PDF viewer, the man command and man pages are not part of the default software. Probably the best way to deal with that is to create a Distrobox container to do one's work in, though having the Distrobox man pages available would be helpful when doing so. (Distrobox documentation is available online, of course, but I've always reached for man pages first.)

One attractive, and seemingly unique, feature that Aeon offers is automatic updates for the operating system, installed Flatpaks, and any distroboxes that one may have set up. It's not unusual to offer system and Flatpak updates, but updating distroboxes is usually a task left to the user. It can become unwieldy quickly if one has several distroboxes set up that need to be updated manually.

According to the RC2 announcement: there are a few features targeting better performance. Aeon is the first openSUSE edition to use the zram kernel module for system swap. This is supposed to improve system performance by avoiding swapping to disk. Aeon's transactional update system is also supposed to automatically choose packages compiled with x86-64-v3 optimizations for CPUs with Advanced Vector Extensions version two (AVX2) extensions, if they are available and the system supports them.

Overall, Aeon looks like a good choice for users who want a minimal, immutable openSUSE GNOME desktop system. It would be especially attractive for users who want a distraction-free system with just a few applications, like an IDE and web browser for development work. It is probably not a great choice for openSUSE users who are happy with Tumbleweed or Leap and installing software with Zypper.

Readers interested in trying openSUSE Aeon should check out the install guide and overview. The distribution is still in a release-candidate stage, so rough edges are to be expected—but it is solid enough to test drive and report bugs if they're found.