Agenda

• Introduction
• History of systemd
• What is systemd?
• Units
• Components of systemd
• Demo time

Introduction

• Creative Commons Attribution 3.0 Netherlands License.
• Sources available on github
• Viewable version
• Built using impress.js, Haml and Sass

History

• First commit 18 Nov 2009
• Publicly announced by Lennart Poetering 30 Apr 2010
• Itch:
  • better init
  • better system management

What is systemd?

systemd

systemd is a suite of basic building blocks for a Linux system.

What is systemd?

• It's not just an init system
• It's an attempt to solve many 'problems'

What is systemd?

systemd

It provides a system and service manager that runs as PID 1 and starts the rest of the system.

What is systemd?

• It's a replacement for init
• It's a replacement for SysV init scripts
• It not only starts processes, it manages them

What is systemd?

systemd

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, supports snapshotting and restoring of the system state, maintains mount and automount points and implements an elaborate transactional dependency-based service control logic.

What is systemd?

• start all services at once (like launchd)
• use kernel socket buffers to avoid waiting
• use cgroups to make sure no processes get lost
• either start a set of services, or don't start any of them

Concepts: Unit

unit

Units encapsulate various objects that are relevant for system boot-up and maintenance.

Concepts: Unit

Examples

• Target (think runlevel)
• Service
• Timer (think cron job)
• Mount
• Device (udev functionality)

Components of systemd

Demo time