CentOS Quick Start Guide E-Book

Shiwang Kalkhanda

• Herausgeber: Packt Publishing
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 301

Veröffentlichungsjahr: 2018

Beschreibung

Linux kernel development has been the worlds largest collaborative project to date. With this practical guide, you will learn Linux through one of its most popular and stable distributions.

This book will introduce you to essential Linux skills using CentOS 7. It describes how a Linux system is organized, and will introduce you to key command-line concepts you can practice on your own. It will guide you in performing basic system administration tasks and day-to-day operations in a Linux environment.

You will learn core system administration skills for managing a system running CentOS 7 or a similar operating system, such as RHEL 7, Scientific Linux, and Oracle Linux. You will be able to perform installation, establish network connectivity and user and process management, modify file permissions, manage text files using the command line, and implement basic security administration after covering this book.

By the end of this book, you will have a solid understanding of working with Linux using the command line.

Leseprobe

CentOS Quick Start Guide

Get up and running with CentOS server administration

Shiwang Kalkhanda

BIRMINGHAM - MUMBAI

CentOS Quick Start Guide

Copyright © 2018 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing or its dealers and distributors, will be held liable for any damages caused or alleged to have been caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

Commissioning Editor: Pavan RamchandaniAcquisition Editor: Siddharth MandalContent Development Editor: Kirk DsouzaTechnical Editor: Adya AnandCopy Editor: Safis EditingProject Coordinator:Hardik BhindeProofreader: Safis EditingIndexer: Rekha NairGraphics:Alishon MendonsaProduction Coordinator:Tom Scaria

First published: December 2018

Production reference: 1241218

Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK.

ISBN 978-1-78934-487-5

www.packtpub.com

To the two most beautiful ladies and pillars of my life, my mother, Mrs. Vijay Lata, and my better half, Reetu.

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Contributors

About the author

Shiwang Kalkhanda (RHCA, RHCSS, MCSE) is a Linux geek and consultant with expertise in the automation of infrastructure deployment and management. He has more than 10 years' experience in security, system, and network administration, and training on open source tech. For most of his automation work, he uses Shell Scripting, Python, and Go. He holds a master's and a bachelor's degree in computer applications. He enjoys traveling and spending time with his children. He is also the author of a book on text processing utilities in Unix-like environments, Learning Awk Programming.

First and foremost, I would like to thank my Guru, Shri Snehamoy Banerjee, for introducing me to the world of Linux and open source.I would like to thank my parents and grandparents for their unconditional love and encouragement throughout my life. To my brother, Pranjal, and my friends, Sanjay Rana, Shreyas Zare, Jugaldeep Sinha, Kapil Bhatnagar, and Lehar Gupta,and all the Packt Publishing staff for their help and guidance throughout the writing process.

About the reviewer

Denis Fateyev holds a master's degree in computer science and has been working with Linux for more than 10 years (mostly with Red Hat and CentOS). He currently works as a Perl and Go system programmer and DevOps for a small international company. For Packt Publishing, he has reviewed several books, mostly related to CentOS, DevOps, and high-availability technologies, including GitLab Cookbook, CentOS High Availability, and CentOS High Performance. A keen participant in the open source community, he is a package maintainer in the Fedora project. Foreign languages (German, Spanish) and linguistics are other passions of his. He can be reached at [email protected].

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Table of Contents

Title Page

Copyright and Credits

CentOS Quick Start Guide

Dedication

About Packt

Why subscribe?

Packt.com

Contributors

About the author

About the reviewer

Packt is searching for authors like you

Preface

Who this book is for

What this book covers

To get the most out of this book

Conventions used

Get in touch

Reviews

Getting Started with CentOS 7

Preparing to install CentOS 7

Getting the right hardware

Getting the software

Finalizing server setup details

Performing manual installation

Accessing the command line using the console

Starting a Terminal

Command-line syntax and structure

Exiting the shell

Introducing the Bash shell

Bash shell and command execution

Tab completion

Command-line editing shortcuts

The history command

Command aliases

Listing current aliases

Setting an alias

Removing an alias

Summary

Command-Line and Filesystem Navigation

Understanding the CentOS 7 filesystem hierarchy

Using man pages and the help command

Different types of documentation available in Linux

Using the man command

Using the GNU info command

Using the help command and the --help option

Other sources of documentation

Managing filenames with path expansion

File globbing

Wildcard expansion

Tilde expansion

Brace expansion

Command substitution

Quoting and escaping

File naming conventions

Managing files using command-line tools

Navigation commands

File management commands

Managing archives and compressed files

Compression

gzip and gunzip compression

bzip2 and bunzip2 compression

xz compression

zip

Archiving

Archiving with tar

Archiving and compression (.gzip) using tar

Archiving, compression (.bzip2), and listing contents using tar

Archiving and compression (.xz) using tar

Summary

Managing Text Files

Different methods to create a text file

Create a text file using the cat command

Create an empty text file using the touch command

Create a text file using the redirection symbol (>)

Create a text file using the echo or printf command

Create a text file using the vi editor

Editing files with the vi editor

Working with files in vi editor

Insert Mode

Line Mode

Determining line numbers in Line Mode of vi editor

How to execute external commands in Line Mode

Command Mode

Using text file manipulation tools

Different types of editor used to view file content

less command

more command

cat command

tac command

head command

tail command

wc command

file command

Viewing compressed files

cut command

sort command

uniq command

paste command

Redirecting output to files and programs

Pipes

tee command

Using grep for text matching

Text extraction using sed and awk

sed

awk

Finding a file (locate and find commands)

Locate

Find

Summary

User and Group Management

Understanding users and groups in CentOS 7

Defining a user

Identifying the current user

Understanding groups in Linux

Executing commands as superuser in CentOS 7

Switching users with the su command

Disadvantages of using the su command to grant root access to a normal user

Using sudo to run commands as the root user

Creating, modifying, or deleting local user accounts

Creating a user with the useradd command

Modifying a user with the usermod command

Deleting a user account with the userdel command

Creating, modifying, or deleting local group accounts

Creating supplementary groups with groupadd

Modifying existing groups with the groupmod command

Deleting a group with the groupdel command

Managing user passwords and aging policies

Setting a user password using the passwd command

Understanding the shadow password file

Understanding password aging parameters

Restricting user access

Fake shell or nologin shell

Summary

Managing File Permissions

Understanding Linux filesystem permissions

Effect of permissions on files and directories

Viewing applied permissions and ownership

Managing file permissions

Modifying file permissions with chmod using symbols

Managing file permissions with chmod using numbers

Managing file ownership

Understanding default ownership

Modifying user ownership with chown

Modifying group ownership with chown

Modifying both user and group ownership with chown

Modifying group ownership with chgrp

Special permissions

Modifying special permissions for files

Modifying special permission, for directories

Using sticky bit

Using setgid

Managing default permissions

Understanding umask

Managing ACL on files

Viewing ACL permissions

Using getfacl

ACL mask

Modifying ACL permissions

Using setfacl

Removing an ACL

Summary

Process Management

Understanding processes

Defining a process

Process creation on a Linux system

Processes types

Interactive processes

Batch processes

Daemons

Threads

Kernel threads

Process states

Viewing current processes

Listing running processes

The ps command

Displaying processes running from the current shell

Displaying all processes by their user

Displaying all processes in different formats

Sorting processes based on different parameters

Displaying processes by user

Displaying process information by name

Displaying process details by PID

Displaying a process hierarchy in a tree style

Displaying the child processes of a parent

Displaying the thread of a process

Displaying the pid of a process if the process name is known

Using the pstree command

Finding the PID of a running process

Using the pgrep command

pidof

The ps command with grep

Communicating with processes using signals

Defining a signal and its types

Sending signals to processes

Sending signals to processes by PID using the kill command

Sending signals to multiple processes by name

killall

pkill

Monitoring processes and load averages

Understanding load averages on Linux

uptime

w

Real-time interactive process monitoring

top

Managing a processes' priority with nice and renice

Understanding priority

Modifying priority

Viewing the priority of a process

Modifying the priority of a new process (nice value)

Modifying the priority of a running process (renice)

Controlling jobs on the command line

Understanding different terms related to job management

Jobs management with its associated controlling Terminal

Foreground processes or jobs

Background processes or jobs

Suspending a foreground process to the background

Managing jobs in the background

Summary

Managing Networking in CentOS

Linux networking concepts

Common terms used in Linux networking

IP address

IPv4

IPv6

Different classes of IP addressing

Public classes

Private classes

Loopback address

Link-local address or APIPA

Netmask

Gateway

Hostname

Nameserver

NetworkManager

Network interface naming conventions

Using Linux networking commands

Viewing IP address details

Using the IP command

Using ifconfig command

Netstat

Viewing the routing information

Using the ip route command

Using route command

Using netstat command

Gateway

Viewing nameserver details

Network troubleshooting utilities

Using ethtool command

Using ping command

Using tracepath command

Using traceroute command

Using mtr command

Verifying DNS connectivity

Using nslookup command

Using host command

Using dig command

Finding local ports and services information

Using the ss command

Using the netstat command

Web utilities

Graphical and non-graphical web browsers

Command-line file downloader (wget)

Command-line download and upload using curl

Managing a network with nmcli

Defining basic terms

Device or interface

Connection

Displaying network information using nmcli

Creating network connections using nmcli

Modifying network interfaces using nmcli

Editing network configuration files

Configuring networking options in static and dynamic modes

Configuring hostnames and name resolutions

Displaying and modifying the hostname

Modifying nameservers (DNS sever)

Accessing remote logins with SSH

Understanding OpenSSH

Executing commands over SSH remotely

Key-based SSH authentication

Configuring ssh-keygen for password-less authentication

Creating a SSH key pair

Configuring and securing SSH logins

Transferring files in Linux

Secure file transfer using SCP

Local to remote filesystem file transfer

Remote to local filesystem file transfer

Synchronizing files using rsync

Synchronizing data locally from one folder to another for backup

Synchronizing data from a local to remote host filesystem

Synchronizing data from remote host to local filesystem

Summary

Software Package Management

Managing applications using RPM

Anatomy of a RPM

What happens when you update an application

Using RPM to query options with RPM packages

Verifying RPM package signatures

Using RPM to install packages

Using rpm to remove packages

Using RPM to upgrade packages

Using RPM to verify packages

Importing a RPM GPG key

Managing applications using YUM

Understanding the YUM package manager

Using the YUM command line

Finding an application using yum

Installing applications using YUM

Displaying packages and their information with YUM

Removing applications using yum

Updating applications and the system using yum

Managing groups of applications using YUM

Using YUM history

Managing application repositories using YUM

Handling other miscellaneous options of yum

Managing official and third-party repositories

Official repositories of CentOS 7

Third-party repositories

Creating custom repositories

Summary

Overview of Essential Advance Utilities

Understanding system logging

Working with rsyslog

Configuring rsyslogd sections

Rsyslogd facilities and priorities

Rsyslogd rules

Log file rotation

Analyzing syslog entries

Monitoring live log file traffic using the tail command

Using the logger command

Working with systemd-journald

Finding events with the journalctl command

Configuring systemd-journald to store logs persistently

Understanding how to control the system and services

Defining essential terms

What is a daemon?

What is a socket?

What is systemd?

What are units?

What is systemctl?

Working with systemd and systemctl

Viewing states of service with systemctl

Viewing unit files with systemctl

Unit dependencies and unit file structure

Managing daemons using systemctl

Masking services

Controlling the boot process using systemd

What are systemd targets?

Switching your targets at runtime

Changing the default target of the system

Understanding SELinux concepts

SELinux contexts

Viewing SELinux context

Working with SELinux

Changing SELinux modes

Using setenforce for runtime changes

Setting default modes of SELinux

Modifying file context

Using restorecon for restoring the default context

Using chon for context management

Using semanage for context management

Modifying port context

Managing SELinux Booleans

Managing SELinux troubleshooting

Using sealert for troubleshooting

Understanding firewall concepts in CentOS 7

Firewalld concepts

Firewalld zones

Firewalld services

Managing firewalld

Using the firewalld-cmd command-line tool

Using the firewalld-config graphical tool

Working with firewalld

Summary

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Preface

This book will provide an introduction to essential Linux skills using CentOS 7. It describes how a Linux system is organized and provides an introduction to key command-line concepts that an individual can practice on their own. It guides an individual in performing basic system administration tasks and day-to-day operations in a Linux environment.

Today, Linux is everywhere. It is an essential ingredient of most technical innovations, powering anything from the tiniest smart devices to the world's most gigantic supercomputer. Linux kernel development has been the world's largest collaborative project hitherto. Readers will learn the basics of Linux and open source technology in modern computing environment. This book will introduce users to CentOS 7 in a concise and practical way. Most of the command lines used in the book are explained with graphics for better understanding.

By the end of this book, you will have a solid understanding of working with Linux using command lines. You will learn core system administration skills for managing a system running CentOS 7, or a similar operating system, such as RHEL 7, Scientific Linux, and Oracle Linux. After reading this book, you will be able to perform installation, establish network connectivity and user and process management, modify file permissions, manage text files using command lines, and implement basic security administration.

Who this book is for

This book is intended for any individual who wants to learn how to use Linux as a server or desktop machine in their environment. Whether you are a developer, fledgling system administrator, or tech lover with no previous Linux administration background, you will be able to start your journey in Linux using CentOS 7 with the help of this book.

Even though this book is written for novice Linux users, a seasoned Linux user will also have something to take away from each chapter. You don't need any prior experience of working with the Linux command line for this book. Most new users of Linux find it difficult to work with the command line and, occasionally, the choice as to which Linux distribution to start with may be confusing. You will learn Linux using CentOS 7, which is one of the most popular and stable Linux distributions based on RHEL 7.

Some of the key features of this book are as follows:

No previous Linux environment experience is required prior to reading this book

Readers will become comfortable with a popular and stable Red Hat Enterprise Linux distribution

Concise content, with a thorough coverage of important utilities

The book is written in such a manner that any computer user with basic familiarity with operating systems can start using it. The only prerequisite is to have some decent hardware on which you can install CentOS 7 and practice the commands covered.

What this book covers

Chapter 1, Getting Started with CentOS 7,establishes the environment for practicing the Linux commands to be covered in forthcoming chapters. You will begin with the installation of CentOS 7, followed by an introduction to the Bash shell environment.

Chapter 2, Command Line and File system Navigation,introduces users to the file system hierarchy, and basic command-line skills, such as navigational commands and backup utilities.

Chapter 3, Managing Text Files,focuses on working with common text manipulating utilities. Readers will learn how to work with the vi editor and input/output redirection in files or in programs.

Chapter 4, User and Group Management,focuses on user management. Readers will learn how to create, modify, or delete users and groups. They will also learn how to manage passwords and their aging policies.

Chapter 5, Managing File Permissions,focuses on managing ownership, permissions, and ACL. Readers will learn how to apply discretionary access controls via permissions and ownership, while also learning how to apply special permissions and ACL to files and directories.

Chapter 6, Process Management,focuses on process management and command-line monitoring. Readers will learn how to interact with processes and modify their priorities to keep systems running smoothly.

Chapter 7, Managing Networking in CentOS,focuses on network management in CentOS 7. Readers will learn how to validate and manage network configurations, including host name, DNS servers, and IP addressing. Readers will also learn remote logins using SSH, and file transfer using SCP and Rsync.

Chapter 8, Software Package Management,focuses on managing software using RPM and Yum. Readers will learn how to keep their systems up to date and install or remove applications by enabling official or third-party repositories.

Chapter 9, Overview of Essential Advance Utilities,focuses on a number of advance utilities related to system logging, system services management, and the securing of systems using firewalld and SELinux.

To get the most out of this book

As always, we have put our best efforts into making this book's content relevant to user requirements. All command lines covered in this book are based on CentOS 7. You can use any minor release of CentOS 7, from CentOS 7.1 through to CentOS 7.6. A CentOS 7 operating system is the only requirement for this book. For beginners, however, it is recommended installing and practicing CentOS 7 in any desktop virtualization application, such as VirtualBox, and VMWare Workstation.

For Windows and macOS users who would like to use a virtual environment, they can use VMWare or VirtualBox to set up CentOS 7 and execute the given command-line examples. For those who are new to Linux, the installation of CentOS 7 is covered in Chapter 1, Getting Started with CentOS 7.

Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "For example, DIRECTORY.. in mkdir usage means we have to insert the directory name we want to use with the mkdir command."

Any command-line input or output is written as follows:

$ mkdir -p -v demo/linux/centos

Bold: Indicates a new term, an important word, or words that you see on screen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Thereafter, the Begin Installation button will be enabled."

Warnings or important notes appear like this.

Tips and tricks appear like this.

Get in touch

Feedback from our readers is always welcome.

General feedback: If you have questions about any aspect of this book, mention the book title in the subject of your message and email us at [email protected].

Errata: Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you have found a mistake in this book, we would be grateful if you would report this to us. Please visit www.packt.com/submit-errata, selecting your book, clicking on the Errata Submission Form link, and entering the details.

Piracy: If you come across any illegal copies of our works in any form on the internet, we would be grateful if you would provide us with the location address or website name. Please contact us at [email protected] with a link to the material.

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Getting Started with CentOS 7

Community Enterprise Operating System, commonly referred to as CentOS, is a fast, stable, and open source enterprise-grade Linux distribution used on laptops, desktops, and servers. It is derived from the source code of Red Hat Enterprise Linux (RHEL), which is developed and maintained by the CentOS community. All proprietary content related to Red Hat Inc. is removed from the CentOS packages, which are then recompiled with CentOS community assets, such as logos and so on. CentOS 7 is an exact replica of RHEL 7, but is available for free with community support and updates. The CentOS project is now officially sponsored by Red Hat Inc. and is most suitable for environments where commercial support for operating systems is not mandatory.

In this chapter, we will give you a walk-through on how to install CentOS 7 on your computers. After installation, we will introduce you to the command-line console of Linux in order to useBash (short for Bourne Again Shell). This chapter teaches you how to set up your environment to perform all the exercises in the following chapters of this book.

In this chapter, we will cover the following:

Preparing to install CentOS 7

Performing manual installation

Accessing the command line using the console

Introducing the Bash shell

Bash shell and command execution

Preparing to install CentOS 7

The CentOS community released its latest operating system version with the name CentOS 7.6-1810, where 7.6 comes from RHEL 7.6 and 1810 shows its release date (October 2018). CentOS 7.6 can be installed on physical or virtual hardware. You can use any of the main desktop virtualization software utilities, such as Oracle VirtualBox (https://www.virtualbox.org/wiki/Downloads) or VMWare Workstation (https://www.vmware.com/products/workstation-pro/workstation-pro-evaluation.html), as per your environment. My choice for desktop virtualization software is VirtualBox as it is free, open-source, and easy to use. You will also need a working internet connection to download the CentOS image from the community download page.

Those are using Linux as their base operating system can also use KVM for virtualization.

Getting the right hardware

For a minimal installation of CentOS 7.6, the following hardware requirements must be met:

512 MB RAM

4 GB HDD space

A network card

However, to practice all the exercises described in this book, we recommend that the following hardware requirements are met:

64-bit architecture support

1 GB RAM

10 GB HDD space

DVD drive or USB memory stick

A network card

Getting the software

There are different ways to get the software required to perform all the exercises in this book. However, the easiest and most flexible way is to download the iso file from the CentOS website and burn it to a DVD, or create a bootable USB drive with CentOS. Then, boot your PC using the ISO DVD image if you are using a virtual machine. If you are installing onto a physical system, then use a bootable USB drive or burned CentOS DVD for installation.

Use the following link to download the CentOS 7.6 (64 bits) ISO image file:

http://centos.mirror.net.in/centos/7.6.1810/isos/x86_64/CentOS-7-x86_64-DVD-1810.iso

You can download MD5 and SHA1 hashes of the image file downloaded from CentOS site. The downloaded image should have the same hash as the one posted on the CentOS website.

Finalizing server setup details

Once you have the right hardware and software for the CentOS installation, you should decide on the basic setup parameters to be specified while performing the installation. The following table lists the details we will use during the installation of our CentOS 7.6 server described in this chapter:

Setup parameter

Sample values

IP address

192.168.0.100

Netmask

255.255.255.0

Hostname

Server.example.com

Root password

Linux@12345

User name

Student

User password

Student@12345

Performing manual installation

Nowadays, the fastest and easiest way to install CentOS is to use a bootable USB drive; however, in our case, I have chosen to use the DVD ISO image with a virtual machine. First, we need to boot the computer system/virtual machine using the DVD. On booting from the DVD, you will get a cool CentOS screen displaying the basic installation options, and testing the media and troubleshooting options.Once your system/virtual machine is up and running with a bootable DVD of CentOS 7, follow these steps to install CentOS on your system:

We have to choose the

Install CentOS 7

option and press

Enter

,

as shown in the following screenshot

.

This will start the graphical installer and ask about the language to be used during the installation process

:

Now,

you will see a

WELCOME TO CENTOS 7

s

creen, prompting you to choose your language and keyboard settings. Choose your respective language and keyboard settings

and

click on the

Continue

button

, as shown in the following screenshot

.

In my case, I have chosen

English

:

After this,

yo

u

will see

a

n

INSTALLATION SUMMARY

screen

.

From this screen, you can specify the settings you want to use for the three

different sections and their sub-sections, as shown in the following screenshot

:

On this screen, the Begin Installation button will remain disabled as long as any setting from a section or subsection displayed on the INSTALLATION SUMMARY screen is still incomplete. If all the sections and subsections displayed on this screen are complete with minimum installation instructions, only then will the Begin Installation button be enabled.

By default, the installer does automatic partitioning for our hard disk. If we want to use the default layout, then we must click on INSTALLATION DESTINATION, and then approve the disk device we want to use for automatic partitioning by clicking on the Done button on the next screen. Thereafter, the Begin Installation button will be enabled and we can install CentOS with a minimal configuration, as shown in the following screenshot:

The minimal installation of CentOS 7 doesn’t have a graphical interface—it has a bare minimum set of packages installed, with limited features available in the command-line interface.

If you are a beginne

r and want to use

CentOS 7 with a

graphical user interface

(

GUI

), then follow these installation instructions. In this step, we'll learn about the usage of CentOS and then modify certain options that need to be configured during installati

on. The

INSTALLATION SUMMARY

scr

een has three sections, as follows:

LOCALIZATION

SOFTWARE

SYSTEM

These three sections are explained as follows:

LOCALIZATION

: This section further contains the following three sub-sections for configuration:

DATE & TIME

KEYBOARD

LANGUAGE SUPPORT

Or these three, the DATE & TIME sub-section is often required to be configured. The other two we have already configured in the previous steps.

In theDATE & TIMEoption, select the time zone that you are in by clicking on your location on the world map. You can also configure your current specificDATE & TIME from this window, as shown in the following screenshot:

We leave theKEYBOARD and LANGUAGE SUPPORTsettings at their defaults, and move to the next section to be configured—in this case,SOFTWARE.

SOFTWARE

:

This section further contains two sub-sections for configuration:

INSTALLATION SOURCE

SOFTWARE SELECTION

Under theSOFTWARE section, we keepINSTALLATION SOURCE set to its default local media (DVD-ROM), as shown in the following screenshot:

The next sub-section for configuration is SOFTWARE SELECTION. This forms an important part of the installation procedure. Click on this option and you will get the screen shown in the following screenshot. From here, you can choose the default base environment and add-ons that are available for the selected environment. For our practice demonstration, we will install the GNOME Desktop base environment with four add-ons: GNOME Applications, Office Suite and Productivity, Development Tools and System Administration Toolsas shown in the following screenshot:

SYSTEM

: This section further contains four sub-sections for configuration:

INSTALLATION DESTINATION

KDUMP

NETWORK & HOST NAME

SECURITY POLICY

In this section, we keep the KDUMP and SECURITY POLICY sub-sections set to their default parameters, and configure the two remaining sub-sections as follows:

Inthe INSTALLATION DESTINATIONsub-section, we specify where we want to install CentOS. Automatic partitioning is selected by default, but wecan create a manual partitioning scheme of our own as per our requirements. As a bare minimum standard, we will create the following three partitions:

Boot partition

:

This partition s

tores bootable files

such as the kernel image, and so on.

Swap partition

:

This is f

or swapping files and programs in and out of the RAM. It is generally twice the size of the RAM.

Root (

/

)

partition

:

This co

ntains the

Linux filesystem.

The following screenshot shows where to click to create manual partitions:

Choose the device onto which to install the OS, and select

I will configure partitioning

. Finally, click on the

Done

button to proceed with the creation of multiple partitions as shown in the following screenshot:

Now, we create a minimum of three partitions in the partition table (

boot

,

swap

, and

/

). In my case, I have kept

File System

as

xfs

, with the

Standard

Partition

type for the

boot

and

/

partitions. For the

swap

partition, the

File System

type is kept as

swap

, as shown in the following screenshot:

Next, on pressing

Done

, you will get the

SUMMARY OF CHANGES

dialog box. Click on the

Accept Changes

button to begin creating on the disk the partitions that we specified in the partition table, as shown in the following

screenshot

:

NETWORK & HOST NAME

: In this final

part of

the installation summary, which we'll configure networking. You can leave the default settings as they are to get the IP address from the DHCP server, or click on

NETWORK & HOST NAME

to set up networking manually. From the dialog box, click on the

IPv4 Settings Tab

, then choose the method as

Manual

from drop-down menu and specify the private IP address, as shown in the following screenshot:

Further in the NETWORK & HOST NAME settings, change the network connection state from Off to On, as shown in the following screenshot:

Now that all the

INSTALLATION SUMMARY

sections are configured as required, the

Begin Installation

button is enabled. Click on the

Begin Installation

button to start the process of installation, as shown in the following

screenshot

:

Next, the screen prompts for user settings. Here, we click

Root Password

first and set the password to

Linux@12345

.

Next, we click on

CREATE USER

to create a user. For both the

Full name

and

User name

fields, enter

student

, and set

Password

as

Student@12345

. Here also we have to click on the

Done

button twice to confirm the password, as shown in the following

screenshot

:

Have a cup of coffee while the installation process is in progress. Once the installation is complete, remove any installation media (the instructions only apply to the DVD method) and click on the

Reboot

button, as shown in the following

screenshot

:

Once the system has rebooted, we will get the INITIAL SETUP screen, where we have to accept an EULA agreement before logging in to the system. Here, we click on

LICENSE INFORMATION

to accept the license agreement, as shown in the following

screenshot

:

Once the license agreement has been accepted, the

FINISH CONFIGURATION

button will become enabled. Click on it to reach the login screen.

On the login screen, click on the

student

username

and enter the password as

Student@12345

, as shown in the following

screenshot

:

After a successful login, you will see the welcome screen that is displayed only when the user LOGS IN for the first time. Click on the

Next

button to reach the desktop.

Congratulations! You have successfully installed the latest version of CentOS 7 on your computer system or virtual machine.

You can explore your new CentOS 7 environment and perform other tasks, such as updating the system or installing other useful software for daily operational requirements. To power down the system, click on the right corner of desktop. You will get a drop-down menu; from there you can click

on

Shut down

, as shown in the following screenshot: