Book Image

Red Hat Enterprise Linux 9 Administration - Second Edition

By : Pablo Iranzo Gómez, Pedro Ibáñez Requena, Miguel Pérez Colino, Scott McCarty
2 (2)
Book Image

Red Hat Enterprise Linux 9 Administration - Second Edition

2 (2)
By: Pablo Iranzo Gómez, Pedro Ibáñez Requena, Miguel Pérez Colino, Scott McCarty

Overview of this book

With Red Hat Enterprise Linux 9 becoming the standard for enterprise Linux used from data centers to the cloud, Linux administration skills are in high demand. With this book, you’ll learn how to deploy, access, tweak, and improve enterprise services on any system on any cloud running Red Hat Enterprise Linux 9. Throughout the book, you’ll get to grips with essential tasks such as configuring and maintaining systems, including software installation, updates, and core services. You’ll also understand how to configure the local storage using partitions and logical volumes, as well as assign and deduplicate storage. You’ll learn how to deploy systems while also making them secure and reliable. This book provides a base for users who plan to become full-time Linux system administrators by presenting key command-line concepts and enterprise-level tools, along with essential tools for handling files, directories, command-line environments, and documentation for creating simple shell scripts or running commands. With the help of command line examples and practical tips, you’ll learn by doing and save yourself a lot of time. By the end of the book, you’ll have gained the confidence to manage the filesystem, users, storage, network connectivity, security, and software in RHEL 9 systems on any footprint.
Table of Contents (26 chapters)
1
Part 1 – Systems Administration – Software, User, Network, and Services Management
9
Part 2 – Security with SSH, SELinux, a Firewall, and System Permissions
14
Part 3 – Resource Administration – Storage, Boot Process, Tuning, and Containers
21
Part 4 – Practical Exercises

Exercise 1 solution

1. Configuring the time zone to GMT

We can check the current system date by executing the date command. At the very last part of the line that is subsequently printed, the time zone will be shown. In order to configure it, we can use the timedatectl command, or alter the /etc/localtime symbolic link.

So, to achieve this goal, we can use one of the following:

  • timedatectl set-timezone GMT
  • rm –fv /etc/localtime; ln –s /usr/share/zoneinfo/GMT /etc/localtime

Now, date should report the proper time zone.

2. Allowing passwordless login to the root user using SSH

Doing this will require the following:

  • SSH must be installed and available (that means installed and started).
  • The root user should have an SSH key generated and added to the list of authorized keys.

First, let’s tackle this with SSH, as seen in the following code snippet:

dnf –y install openssh-server; systemctl enable sshd; systemctl...