systemd System and Service Manager

What is this?

systemd is a suite of basic building blocks for a Linux system. It provides a system and service manager that runs as PID 1 and starts the rest of the system. systemd provides aggressive parallelization capabilities, uses socket and D-Bus activation for starting services, offers on-demand starting of daemons, keeps track of processes using Linux control groups, maintains mount and automount points, and implements an elaborate transactional dependency-based service control logic. systemd supports SysV and LSB init scripts and works as a replacement for sysvinit. Other parts include a logging daemon, utilities to control basic system configuration like the hostname, date, locale, maintain a list of logged-in users and running containers and virtual machines, system accounts, runtime directories and settings, and daemons to manage simple network configuration, network time synchronization, log forwarding, and name resolution. See Lennart’s blog story for a longer introduction, and the three status updates since then. Also see the Wikipedia article. If you are wondering whether systemd is for you, please have a look at this comparison of init systems by one of the creators of systemd.

License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

Spelling

Yes, it is written systemd, not system D or System D, or even SystemD. And it isn’t system d either. Why? Because it’s a system daemon, and under Unix/Linux those are in lower case, and get suffixed with a lower case d. And since systemd manages the system, it’s called systemd. It’s that simple. But then again, if all that appears too simple to you, call it (but never spell it!) System Five Hundredsince D is the roman numeral for 500 (this also clarifies the relation to System V, right?). The only situation where we find it OK to use an uppercase letter in the name (but don’t like it either) is if you start a sentence with systemd. On high holidays you may also spell it sÿstëmd. But then again, Système D is not an acceptable spelling and something completely different (though kinda fitting).

Plus

Hackfests and Sprints

Mailing Lists

Bug Reports

Also check out various distributions bugtrackers:

IRC

#systemd on irc.freenode.org

Download

https://github.com/systemd/systemd/tags

Most Importantly, Git

https://github.com/systemd/systemd

Package repositories of the various distributions

Fedora: packages, wiki
openSUSE: packages, instructions
Arch Linux: packages, wiki
Debian: packages, wiki
Ubuntu: packages, wiki
Mageia: packages
Gentoo: packages, wiki

Continuous Integration

Publications

Article in The H
Article in The H, Part 2
Bê-á-bá do systemd #1, #2, #3, #4, #5, #6 (Brazilian Portuguese)
Évolutions techniques de systemd (French)
RHEL7 docs
SUSE White Paper on systemd

Manuals and Documentation for Users and Administrators

Videos for Users and Administrators

The systemd for Administrators Blog Series

Also available: a Russian translation; another, more complete Russian translation as PDF; a Vietnamese translation

All about systemd