Mastering Linux Administration: A comprehensive guide to installing, configuring, and maintaining Linux systems in the modern data center

772 Pages·2021·33.19 MB·english

by  Alexandru Calcatinge

Mastering Linux
Administration
A comprehensive guide to installing, configuring,
and maintaining Linux systems in the modern
data center
Alexandru Calcatinge
Julian Balog
BIRMINGHAM—MUMBAI
Mastering Linux Administration
Copyright © 2021 Packt Publishing
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Contributors
About the authors
Alexandru Calcatinge is an open-minded architect with a background in computer science and
mathematics, and is constantly eager to learn new things. He is a senior university lecturer with
a PhD in urban planning and regional development. With 13 years of experience in architectural
programming and development, Alex teaches students about smart cities, big data, and open
source technologies. He has authored four books and numerous scientific articles on urban and
regional planning, with an emphasis on open source technologies in urban and rural development.
Alex started using Linux in 2009 and never looked back. He has also been a certified Linux trainer
since 2017 and teaches Ubuntu Server administration to students in Bucharest, Romania. Alex
loves the DevOps philosophy and the possibilities that cloud technologies bring to the future. He
is a certified programming analyst, computer network administrator, trainer, and designer.
For my wife, Rodica. You always stand by my side and offer me support,
compassion, and guidance. For my sister and my parents. In memory of
Bogdan Paul, who left too early to read the book.
Julian Balog is a senior software engineer with more than 15 years of experience in the
industry. His primary work currently focuses on application delivery controllers, containerized
workflows, networking, and security. With a never-ending passion for Linux and open source
technologies, Julian is always in pursuit of learning new things while solving problems and
making things work through simple, efficient, and practical engineering.
He lives with his wife, two children, and an Aussie-doodle in the greater Seattle area, Washington.
For Adelina, Anouk, and Indio. You graciously endured my absence while I was
working on the book. Remembering Eduard, who sparked my love for Linux.
The authors would like to thank the wonderful editorial and production team
at Packt for their professional leadership, dedication, and guidance throughout
the writing of this book. We are indebted to Neil D'mello, Nihar Kapadia, Preet
Ahuja, Hemangi Lotlikar, Rahul D'souza, Sulagna Mohanti, for many helpful
suggestions and the comprehensive revision of the drafts. We are also grateful to
Marcus Patman for his thorough reviews and critical comments. We could not
hope for a better team and support.
About the reviewer
Marcus Patman is a senior systems engineer with over 20 years' experience as an IT
professional. He has worked in many environments, ranging from small startups to large
enterprises with thousands of production servers. During this time, he has worked with
multiple platforms, including Linux, Windows, AWS, and Azure. He currently manages an
enterprise Linux environment for a non-profit, providing automation and management of
their on-premises and cloud systems.
Thanks to all my colleagues past and present for allowing me to do
what I do best.
Love to my friends Mary and Jay for encouraging me pursue a career in
technology. I couldn't have done it without you.
Table of Contents
Preface
Section 1: Linux Basic Administration
1
Installing Linux
Technical requirements 4 Installing Linux graphical
The Linux operating system 4 user interfaces 28
Linux distributions 5 GNOME 28
KDE 30
Choosing the right Linux
distribution 6 Setting up and using the
Common Linux distributions 9 Linux workstation 34
Linux distributions – a practical guide 10 Installing Ubuntu Desktop 34
Default software packages 35
Installing Linux – the basics 13
Additional software packages 37
How to install Linux 13
Managing software packages with APT 40
Installing Ubuntu 17
Installing CentOS 20 Summary 43
Questions 44
The Windows Subsystem
for Linux (WSL) 25
2
The Linux Filesystem
Technical requirements 45 The command-line prompt 53
Introducing the Linux shell 46 Shell command types 53
Command structure 54
Bash shell features 47
Help from the manual 55
The shell connection 51
ii Table of Contents
The Linux filesystem 55 Commands for file properties 71
Directory structure 56 Using text editors to create and
edit files 85
Working with files and
directories 57 Summary 88
Questions 89
Understanding file paths 58
Basic file operations 59 Further reading 90
Commands for file viewing 69
3
Linux Software Management
Technical requirements 92 Application streams in CentOS 8 113
Linux software package types 92
Building a package from source 113
The DEB and RPM package types 92
The source code file 114
The snap and flatpak package types 95
Preparing the source code 117
Managing software packages 97 Setting up the environment 118
Managing DEB packages 97 Summary 121
Managing RPM packages 103
Questions 121
Using snap and flatpak packages 106
Further reading 122
4
Managing Users and Groups
Technical requirements 124 Creating, modifying, and deleting
groups 138
Managing users 124
Understanding sudo 125 Managing permissions 152
Creating, modifying, and deleting users 126
File and directory permissions 153
Managing groups 137
Summary 166
Questions 166
5
Working with Processes, Daemons, and Signals
Technical requirements 168 Understanding process types 168
Introducing processes 168 The anatomy of a process 176
Table of Contents iii
Working with processes 182 Exploring interprocess
communication 198
The ps command 182
The pstree command 186 Shared storage 198
The top command 187 Shared memory 199
The kill and killall commands 190 Unnamed pipes 200
The pgrep and pkill commands 192 Named pipes 201
Message queues 203
Working with daemons 193
Sockets 204
Working with SysV daemons 194
Working with signals 206
Working with systemd daemons 195
Summary 210
Questions 211
Section 2: Advanced Linux Server
Administration
6
Working with Disks and Filesystems
Technical requirements 215 Understanding disks and
partitions 224
Understanding devices in Linux 216
Linux abstraction layers 216 Common disk types used 224
Partitioning disks 225
Device files and naming conventions 218
Understanding filesystem Logical Volume Management
types in Linux 220 in Linux 235
LVM snapshots 238
The Ext4 filesystem features 221
The XFS filesystem features 222
Summary 241
The btrfs filesystem features 222
7
Networking with Linux
Technical requirements 244 TCP/IP protocols 251
Exploring basic networking 244 IP addresses 254
Sockets and ports 259
Computer networks 244
Linux network configuration 260
The OSI model 246
The TCP/IP model 250
iv Table of Contents
Working with networking Remote access 285
services 268
Understanding network
DHCP servers 268
security 293
DNS servers 270
VPNs 294
Authentication servers 275
Working with VPNs 294
File sharing 276
Setting up OpenVPN 295
Printer servers 278
File transfer 279 Summary 302
Mail servers 280
Questions 303
NTP servers 283
8
Configuring Linux Servers
Technical requirements 306 Questions 306
GitHub 306 Further reading 306
9
Securing Linux
Technical requirements 308 Introducing netfilter 345
Understanding Linux security 308 Working with iptables 346
Introducing nftables 352
Introducing SELinux 310
Using firewall managers 357
Working with SELinux 310
Summary 371
Introducing AppArmor 332
Questions 372
Working with AppArmor 332
Further reading 372
Final considerations 341
Working with firewalls 341
10
Disaster Recovery, Diagnostics, and Troubleshooting
Technical requirements 374 Risk calculation 376
Planning for disaster recovery 374 Designing a disaster recovery plan 378
A very short introduction to risk
management 374
Table of Contents v
Backing up and restoring system issues 390
the system 379 Tools for troubleshooting
Disk cloning solutions 380 network issues 402
Tools for troubleshooting
Introducing common
hardware issues 411
Linux diagnostic tools for
troubleshooting 388 Summary 413
Exercises 414
Tools for troubleshooting boot issues 388
Tools for troubleshooting general Further reading 414
Section 3: Cloud Administration
11
Working with Containers and Virtual Machines
Technical requirements 418 Understanding the underlying
container technology 441
Introduction to virtualization
on Linux 418 Understanding Docker 444
Efficiency in resource usage 418 Working with Docker 447
Introduction to hypervisor 420
Which Docker version to choose? 447
Understanding VMs 420
Installing Docker CE 447
Choosing the hypervisor 421
Using the Docker commands 451
Understanding Linux Managing Docker containers 453
containers 440 Deploying a containerized application
with Docker 456
Containers versus VMs 440
Summary 458
Further reading 459
12
Cloud Computing Essentials
Technical requirements 462 Knowing the key features of cloud
computing 471
Introduction to cloud
technologies 462
Short introduction to
Understanding the need for cloud OpenStack 471
computing standards 463
Introducing IaaS solutions 475
Knowing the architecture of the cloud 466
Amazon EC2 475