Book Image

Linux Service Management Made Easy with systemd

4.5 (2)
Book Image

Linux Service Management Made Easy with systemd

4.5 (2)

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

Comparing NTP implementations

The Original Guy (OG), or reference implementation, of the NTP world is ntpd. It was created way back in the 1980s and served us well for a long time. You can use it on client machines to keep their time synchronized, or you can set it up as a time server. However, it does have several shortcomings, including numerous security problems that were found during a code audit in 2017.

The chrony implementation, which can also be used as either a client or a server, was created from scratch to fix the shortcomings of ntpd. Unlike ntpd, chrony has the following features:

  • It works well on computers that have unstable network connections or that get turned off for long periods.
  • It works better with virtual machines.
  • It can adjust itself better when the speed of the hardware clock oscillator fluctuates due to a temperature change.
  • It can achieve sub-microsecond accuracy by using hardware timestamping and a hardware reference clock.
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