The Debian project has announced the new stable version of its operating system, codenamed “Jessie.” The new OS marks the shift to systemd, which replaces the previously used SystemV, and many more improvements.
Debian 8 contains 24,573 updated packages, amounting to 66% of all packages in the previous stable release, but the single biggest change has undoubtedly been the introduction of systemd.
Systemd is a suite of daemons, libraries, and utilities aimed at enabling system management and configuration. The decision to enable systemd by default was highly controversial inside the Debian project and led to forking Debian into a new distribution, Devuan. Among the main reasons for criticism against systemd is its “hugely invasive and hardly justified” architecture which is felt by some developers as going against the basic UNIX philosophy of favouring small independent programs specialized on just one single task. It must be noted, anyway, that, although systemd comes installed by default in Debian 8, it can be disabled at install time. Updating an older Debian version to Jessie could entail some work to update existing sysvinit init scripts to make them compatible with systemd. According to Scott Gilbertson, reporting for Ars Technica, there are indeed several cases where init scripts will fail, such as those that use the $HOME variable or tools like /sbin/chkconfig, and the systemd incompatibilities list is a necessary read.
Besides systemd, Debian 8 introduces support for two new architectures: arm64 and ppc64, bringing the total number of supported architectures to ten. Debian 8 also removes three previously supported architectures, including IA–64 and Sparc due to insufficient developer support. Furthermore, Debian 8 disables the legacy secure sockets layer protocol SSLv3 and many cryptography libraries and applications have been built without support for it.
Debian, says the Debian project in the announcement, may be upgraded “painlessly, in place, without any forced downtime,” although it strongly recommends to read the release notes as well as the installation guide. Debian 8 will be supported for the next 5 years.