systemd for Linux SysAdmins
systemd. Yes, in full lowercase. If there was ever a technology to cause controversy in the Linux world, this is it. Since its inception in 2010, systemd’s goals were set quite high: to replace the vital part in every Linux system that takes care of the system boot process. It quickly reached maturity, allowing it to be adopted as the main init system in most major distributions just five years later. Despite describing events that happened over a decade ago, systemd adoption still raises the temperature in any Linux-related discussion.
David Both’s comprehensive book tackles the what, why, and how issues surrounding systemd. Carefully divided into 16 chapters, going from the basics and some of the technical and political history behind the project to the different subsystems and aspects covered by systemd, its almost 450 pages can scare people away. But the text is written in a very clear, tutorial-like fashion, and while it can be read sequentially, cover-to-cover, readers can also pick a single aspect and jump straight to the relevant chapter.
A frequent criticism of the systemd project is that it aims to basically rewrite all of a Linux system, and just looking at this book’s index shows there is some truth to it. The first chapter is an introduction to the systemd project and a brief overview of its history (including the controversies around it), and the following four chapters deal with understanding and controlling the system boot process.
That leaves ten chapters to cover different aspects or subprojects of systemd, such as time and date issues (synchronization, time specifications, and controlling repetitive tasks), understanding and leveraging the system journal that strongly departs from the old syslog system, network configuration and firewall management, system health and performance debugging–all aspects that in the traditional Unix philosophy were managed by independent programs. And I can identify several systemd subprojects not covered by this book!
We long-time Unix and Linux administrators took pride in how highly performant and stable systems were supported by the simplicity of our tools; systemd critics point out this massive project has absorbed dozens of individual tools, yielding corporate control over vast swaths of vital system tooling. Truth is, as a sysadmin myself, systemd is today one of my greatest allies.
I appreciate how the author evaluates every component independently, including his personal evaluation of each–even acknowledging when he prefers working with the traditional programs.
If I had to note one criticism: given the many console captures, having a maximum width below 70 characters means several lines are unnaturally cut short (and continued with odd indentations). There is probably no “right” way to solve this, but it does affect the reading experience.