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Flatpak, Snap, and AppImage

Triathlon

Article from ADMIN 45/2018

By Valentin Höbel

The Flatpak, Snap, and AppImage package formats work across distributions, but each has its specific disadvantages.

Distributions offer convenient tools for retrieving programs and other software components. Package managers such as Apt or Yum let you search for, download, and install software in the form of packages.

Classic formats for packages provide one package per piece of software; the package then contains the desired software and some metadata. The latter includes information, such as the name, version, and author of the software, as well as other software dependencies. The package manager parses the metadata and carefully resolves all the dependencies so that installing a package can trigger a number of additional downloads and installations.

As a result, you achieve a state in which the desired program is executable from disk, thanks to meeting the dependencies. Don't forget that installing other software with the same dependencies is far faster now because the required packages are already available. This means that several packages can use the same components (e.g., OpenSSL).

These typical package management systems, however, are specific to a distribution and suffer from various weaknesses (discussed in the next section). For more than a decade, now, developers have looked at the basic principle of a cross-distribution run-time environment for programs and have designed various modern formats that solve some of the problems. Once packaged, the applications run wherever the appropriate environment is available – whether under openSUSE, Ubuntu, or Fedora.

These modern approaches come from different communities or companies and have therefore not necessarily developed in the same direction. To find out which formats might prevail in the future and which are recommended, it is worth taking a look at the three best-known representatives of the genre: Flatpak, Snap, and AppImage.