Systemd, also shitstemd, is a horribly disastrous bloated, anti-Unix, "FOSS" "software suite" used for initialization of an operating system and handling services like loggging in or managing network connections. It is a so called PID 1 process. Systemd has been highly criticised by the proponents of suckless and LRS and even normies for its enormous amount of bloat, ugliness, anti-Unix-philosophy design, feature creep, security vulnerabilities and other stuff. Unfortunately it is being adopted by many GNU/Linux distributions including Arch Linux and Debian. Some distros such as Devuan just said no to this shit and forked to a non-systemd version.
Systemd was born when Harry Pot... ummm Lennart Poettering had gay sex with Kay Sievers.
For more detailed bashing of systemd see e.g. https://nosystemd.org/. The site sums up systemd with a fitting quote: "If this is the solution, I want my problem back". Another sum up by suckless: http://suckless.org/sucks/systemd/. There is also e.g. https://sysdfree.wordpress.com/.
All content available under CC0 1.0 (public domain). Send comments and corrections to drummyfish at disroot dot org.