Rudareanu Viorel, Baturin Daniil / Рудареву Виорел, Батурин Даниил - Linux for System Administrators: Navigate the complex landscape of the Linux OS and command line for effective administration / Linux для системных администраторов [2023, PDF, EPUB,

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Preface xiii
Part 1: Linux Basics
1
Getting to Know Linux 3
The structure of a Linux system 3
The Linux kernel and Linux-
based operating systems 3
Kernel versus user space 4
The Linux kernel and the GNU project 5
Open source software licenses 6
Permissive and copyleft licenses 7
Patent grant, tivoization, and SaaS concerns 7
Linux distributions 8
Package managers and package repositories 8
Differences between distributions 9
Linux usage in the modern world 10
Summary 10
2
The Shell and Its Commands 13
What is a shell? 13
Basic shell commands 17
Intermediate shell commands 19
Summary 22
3
The Linux Filesystem 23
What is a filesystem? 23
High scalability 26
High performance 26
What filesystem does my system use? 26
Table of Contents
FUSE filesystem 27
The directory tree and
standard directories 28
Links (hard and symbolic) 30
What is an inode? 30
What is a hard link? 31
What are symbolic links? 31
Mounting and unmounting
filesystems 31
How to unmount the filesystem 32
Pseudo-filesystems 32
Processes 32
Kernel and system information 34
CPU usage 34
Summary 35
4
Processes and Process Control 37
Executables versus processes 37
Process termination and exit codes 39
Exit codes 39
Signals 41
The kill command 42
The process tree 44
Process search and monitoring 45
The ps command 45
Process monitoring tools 47
The /proc filesystem 48
Summary 49
5
Hardware Discovery 51
Discovering CPU model and features 51
Feature discovery on different platforms 52
The /proc/cpuinfo file 52
Multi-processor systems 54
High-level CPU discovery utilities 57
Memory discovery 58
Discovering PCI devices 59
Discovering USB devices 60
Discovering storage devices 61
High-level discovery tools 62
dmidecode 62
lshw 64
Summary 67
Part 2: Configuring and Modifying Linux Systems
6
Basic System Settings 71
Overview of basic settings 71
The hosts configuration file 73
The resolv configuration file 75
The network-scripts configuration file 76
The dhclient configuration file 79
The sysctl configuration file 81
Summary 82
7
User and Group Management 83
Overview of managing
accounts/groups 83
How to add a new account 85
Using useradd 85
Using adduser 86
How to delete an account 87
Understanding the/etc/sudoers file 88
Switching users 88
Managing account passwords 89
Locking/unlocking user accounts 90
Setting password expiration 90
Group management 92
Permissions 94
Changing groups 96
Summary 98
8
Software Installation and Package Repositories 99
Software installation, packages,
and dependencies 99
Package managers 101
Package files 102
Inspecting package files 103
Inspecting installed packages 111
Installing and removing package files 115
Package repositories and
high-level package managers 117
Package repositories 117
High-level package managers 120
Searching for packages 124
System upgrade 126
Upgrading a system with YUM or DNF 126
Upgrading a system with APT 127
Summary 129
Further reading 129
9
Network Configuration and Debugging 131
Linux network stack 131
Network interfaces and
addresses in Linux 133
Discovering physical network devices 134
Network interface names 136
Using the ip command 136
Discovering and inspecting logical links 137
Viewing and changing Ethernet l
ink MAC addresses 138
Viewing and changing IP addresses 139
Routes and neighbor tables 141
ARP and NDP neighbor tables 142
Routes and route tables 143
NetworkManager 149
Distribution-specific
configuration methods 152
Debian 153
Old Red Hat-based distributions 153
Network troubleshooting 154
Using ping 154
Using traceroute 155
Summary 156
10
Storage Management 157
Adding additional storage volumes 157
Formatting and partitioning
storage devices 159
Formatting a newly created partition 164
Mounting and unmounting volumes 164
Updating the /etc/fstab file 165
Editing /etc/fstab file 166
Utilizing LVM 167
Getting started with LVM 167
Creating a format for logical disks 170
Deleting volumes with LVM 172
Summary 172
Part 3: Linux as a Part of a Larger System
11
Logging Configuration and Remote Logging 175
Logging configuration 175
How does log data get sent
and gathered? 177
Checking rsyslog service
on all servers 178
Configuring rsyslog for
centralized logging 180
Sending logs to a centralized
rsyslog server 182
Log rotation 184
Journald 185
DMESG 189
Understanding the ring buffer
in Linux 190
Summary 193
12
Centralized Authentication 195
The AAA framework 195
Authentication mechanisms
in Linux 196
Information lookup 196
Name Service Switch 197
Pluggable Authentication Modules 198
PAM configuration 199
Limitations of PAM 202
System Security Services Daemon 202
Active Directory authentication
with Samba 4 202
Setting up the domain controller 203
Setting up the client 206
Summary 207
Further reading 207
13
High Availability 209
Types of redundancy and
load balancing 209
Link layer redundancy 212
Network layer redundancy and
load balancing 213
Transport layer load balancing with LVS 214
LVS load-balancing methods 216
Saving and restoring LVS configurations 220
Additional LVS options 220
Active/backup configurations and
load balancing with Keepalived 221
Installing Keepalived 222
Basics of the VRRP protocol operation 222
Configuring VRRP 223
Configuring virtual servers 226
Application layer load balancing 231
Web application load balancing
with HAProxy 232
Summary 233
Further reading 233
14
Automation with Chef 235
Overview of infrastructure
automation 235
Benefits of automation in Linux 236
Introduction to Chef 236
What is Chef? 236
Key features of Chef 236
Overview of Chef ’s architecture 237
Chef server 237
Chef server components 238
Cookbooks and recipes 238
Chef workstation 238
Development workflow 239
Managing environments and roles 239
Chef nodes 242
Node registration 242
Communication with the Chef server 242
Cookbook development 243
Cookbook structure and components 243
Writing recipes and resources 243
Managing infrastructure
with Chef 245
Configuration management 245
Chef client-server interaction 245
Reporting and monitoring 246
Data synchronization 246
Benefits of automating
infrastructure with Chef in Linux 247
Consistency and scalability 247
Reduced human error 247
Enhanced security 247
Challenges and best practices 247
Best practices for effective Chef
implementation 247
Summary 248
15
Security Guidelines and Best Practices 249
Common threats and attack types 249
The motivation of attackers and
the possible consequences 249
Information security properties and
attacks on them 250
Keeping your system secure 254
Reducing the attack surface 254
Compartmentalization and
privilege separation 255
Preventing credential theft and
brute-force attacks 258
Reducing the risk of software vulnerabilities 259
Summary 260
Further reading 260
Index 261
Other Books You May Enjoy 272