CentOS 8 Essentials

Neil Smyth

• Publisher: Packt Publishing
• Year: 2020
• ISBN:
  9781800562028
• Edition: 1
• Topic: Computer Science
• Subtopic: Operating Systems
• Index: Computer Science

Learn how to install, use, and administer CentOS 8 with the help of expert guidance and engaging examplesKey Features• Become familiar with a popular and stable Red Hat Enterprise Linux distribution• Gain a thorough overview of the operating system by learning concepts such as disk partitioning, KVM virtualization, and more• Explore advanced topics such as logical volume management and firewall configurationBook DescriptionLinux kernel development is perhaps the world's largest collaborative project to date. With CentOS 8 Essentials, you'll be given easily accessible information to install, use, and administer the CentOS 8 distribution.The book begins with a concise history of the Linux operating system and CentOS. You'll then learn how to install CentOS 8 using the dual boot configuration so that it can coexist with Windows on the same drive. After installing CentOS, you'll learn GNOME 3 — the desktop environment included with CentOS 8 that helps you navigate through the distribution. As you progress, you'll explore the Cockpit web interface that enables you to perform tasks via a web browser instead of using the command-line. You'll then take a brief tour of the Bash shell environment and learn ways to administer a system that doesn't have a desktop or a Cockpit interface. While learning advanced concepts, you'll see how to manage swap space efficiently and control the performance of CentOS 8.By the end of the book, you'll have all the essential information you need to comfortably start using the CentOS 8 distribution.What you will learn• Work in dual boot environments• Install and manage packages with App Streams• Perform systemd unit configuration tasks using the systemctl command-line tool• Configure the RHEL 8 firewall• Share files with Linux and Windows systems using Samba and NFS• Deploy KVM-based virtual machinesWho this book is forCentOS 8 Essentials is an ideal book for you if you want essential information to start using the CentOS 8 distribution. Whether you are a developer, a system administrator, or a tech lover with no previous Linux administration background, you'll be able to start your adventure with this book.

1. Introduction

CentOS 8 Essentials is designed to provide detailed information on the installation, use and administration of the distribution. For beginners, the book covers topics such as operating system installation, the basics of the GNOME desktop environment, configuring email and web servers and installing packages and system updates using App Streams. Additional installation topics such as dual booting with Microsoft Windows are also covered, together with all important security topics such as configuring a firewall and user and group administration.

For the experienced user, topics such as remote desktop access, the Cockpit web interface, logical volume management (LVM), disk partitioning, swap management, KVM virtualization, Secure Shell (SSH), Linux Containers and file sharing using both Samba and NFS are covered in detail to provide a thorough overview of this enterprise class operating system.

1.1 Superuser Conventions

CentOS 8, in common with Linux in general, has two types of user account, one being a standard user account with restricted access to many of the administrative files and features of the operating system, and the other a superuser (root) account with elevated privileges. Typically, a user can gain root access either by logging in as the root user, or using the su - command and entering the root password. In the following example, a user is gaining root access via the su - command:

[neil@centos8-demo ~]$ su -

Password:

[root@centos8-demo ~]#

Note that the command prompt for a regular user ends with a $ sign while the root user has a # character. When working with the command-line, this is a useful indication as to whether or not you are currently issuing commands as the root user.

Alternatively, a single command requiring root privileges may be executed by a non-root user via the sudo command. Consider the following attempt to update the operating system with the latest patches and packages:

[neil@centos8-demo ~]$ dnf update

Not root, Subscription Management repositories not updated

Error: This command has to be run under the root user.

Optionally, user accounts may be configured so that they have access to root level privileges. Instead of using the su - command to first gain root access, user accounts with administration privileges are able to run otherwise restricted commands using sudo.

[neil@centos8-demo]$ sudo dnf update

We trust you have received the usual lecture from the local System

Administrator. It usually boils down to these three things:

#1) Respect the privacy of others.

#2) Think before you type.

#3) With great power comes great responsibility.

[sudo] password for neil:

Updating Subscription Management repositories.

.

.

The reason for raising this issue so early in the book is that many of the command-line examples outlined in this book will require root privileges. Rather than repetitively preface every command-line example with directions to run the command as root, the command prompt at the start of the line will be used to indicate whether or not the command needs to be performed as root. If the command can be run as a regular user, the command will be prefixed with a $ command prompt as follows:

$ date

If, on the other hand, the command requires root privileges, the command will be preceded by a # command prompt:

# dnf install openssh

1.2 Feedback

We want you to be satisfied with your purchase of this book. If you find any errors in the book, or have any comments, questions or concerns please contact us at [email protected].

1.3 Errata

While we make every effort to ensure the accuracy of the content of this book, it is inevitable that a book covering a subject area of this size and complexity may include some errors and oversights. Any known issues with the book will be outlined, together with solutions, at the following URL:

https://www.ebookfrenzy.com/errata/centos8.html

In the event that you find an error not listed in the errata, please let us know by emailing our technical support team a...

Table of contents

• 1. Introduction
• 2. A Brief History of CentOS Linux
• 3. Installing CentOS 8 on a Clean Disk Drive
• 4. Dual Booting CentOS 8 with Windows
• 5. Allocating Windows Disk Partitions to CentOS 8
• 6. A Guided Tour of the GNOME 3 Desktop
• 7. An Overview of the CentOS 8 Cockpit Web Interface
• 8. Using the Bash Shell on CentOS 8
• 9. Managing CentOS 8 Users and Groups
• 10. Understanding CentOS 8 Software Installation and Management
• 11. Configuring CentOS 8 systemd Units
• 12. CentOS 8 Network Management
• 13. Basic CentOS 8 Firewall Configuration with firewalld
• 14. Configuring SSH Key-based Authentication on CentOS 8
• 15. CentOS 8 Remote Desktop Access with VNC
• 16. Displaying CentOS 8 Applications Remotely (X11 Forwarding)
• 17. Using NFS to Share CentOS 8 Files with Remote Systems
• 18. Sharing Files between CentOS 8 and Windows Systems with Samba
• 19. An Overview of Virtualization Techniques
• 20. Installing KVM Virtualization on CentOS 8
• 21. Creating KVM Virtual Machines using Cockpit and virt-manager
• 22. Creating KVM Virtual Machines with virt-install and virsh
• 23. Creating a CentOS 8 KVM Networked Bridge Interface
• 24. Managing KVM using the virsh Command-Line Tool
• 25. An Introduction to Linux Containers
• 26. Working with Containers on CentOS 8
• 27. Setting Up a CentOS 8 Web Server
• 28. Configuring a CentOS 8 Postfix Email Server
• 29. Adding a New Disk Drive to a CentOS 8 System
• 30. Adding a New Disk to a CentOS 8 Volume Group and Logical Volume
• 31. Adding and Managing CentOS 8 Swap Space
• Index