Book Image

Linux Service Management Made Easy with systemd

4 (1)
Book Image

Linux Service Management Made Easy with systemd

4 (1)

Overview of this book

Linux Service Management Made Easy with systemd will provide you with an in-depth understanding of systemd, so that you can set up your servers securely and efficiently.This is a comprehensive guide for Linux administrators that will help you get the best of systemd, starting with an explanation of the fundamentals of systemd management.You’ll also learn how to edit and create your own systemd units, which will be particularly helpful if you need to create custom services or timers and add features or security to an existing service. Next, you'll find out how to analyze and fix boot-up challenges and set system parameters. An overview of cgroups that'll help you control system resource usage for both processes and users will also be covered, alongside a practical demonstration on how cgroups are structured, spotting the differences between cgroups Version 1 and 2, and how to set resource limits on both. Finally, you'll learn about the systemd way of performing time-keeping, networking, logging, and login management. You'll discover how to configure servers accurately and gather system information to analyze system security and performance. By the end of this Linux book, you’ll be able to efficiently manage all aspects of a server running the systemd init system.
Table of Contents (23 chapters)
1
Section 1: Using systemd
12
Section 2: Understanding cgroups
16
Section 3: Logging, Timekeeping, Networking, and Booting

Understanding the purpose of systemd targets

The legacy SysVinit system has runlevels, which define which services are to automatically start when the operating system enters a certain run state. For example, entering the graphical runlevel would bring up all of the services that allow the graphical mode to properly function. In systemd, we have targets instead of runlevels. Several of these targets perform the same function that runlevels used to. That part is easy to understand.

Where the confusion comes in is that targets are more than just runlevels. As we'll soon see, there are many different targets, all with their own specific purposes. In systemd, a target is a unit that groups together other systemd units for a particular purpose. The units that a target can group together include services, paths, mount points, sockets, and even other targets.

By doing a systemctl list-units -t target command, you can see all of the active targets on your system, which should look...