UNIX and Linux System Administration Handbook

"As an author, editor, and publisher, I never paid much attention to the competition-except in a few cases. This is one of those cases. The UNIX System Administration Handbook is one of the few books we ever measured ourselves against."

-Tim O'Reilly, founder of O'Reilly Media

"This edition is for those whose systems live in the cloud or in virtualized data centers; those whose administrative work largely takes the form of automation and configuration source code; those who collaborate closely with developers, network engineers, compliance officers, and all the other worker bees who inhabit the modern hive."

-Paul Vixie, Internet Hall of Fame-recognized innovator and founder of ISC and Farsight Security

"This book is fun and functional as a desktop reference. If you use UNIX and Linux systems, you need this book in your short-reach library. It covers a bit of the systems' history but doesn't bloviate. It's just straight-forward information delivered in a colorful and memorable fashion."

-Jason A. Nunnelley

UNIX® and Linux® System Administration Handbook, Fifth Edition, is today's definitive guide to installing, configuring, and maintaining any UNIX or Linux system, including systems that supply core Internet and cloud infrastructure.

Updated for new distributions and cloud environments, this comprehensive guide covers best practices for every facet of system administration, including storage management, network design and administration, security, web hosting, automation, configuration management, performance analysis, virtualization, DNS, security, and the management of IT service organizations. The authors-world-class, hands-on technologists-offer indispensable new coverage of cloud platforms, the DevOps philosophy, continuous deployment, containerization, monitoring, and many other essential topics.

Whatever your role in running systems and networks built on UNIX or Linux, this conversational, well-written guide will improve your efficiency and help solve your knottiest problems.

Autorentext

Evi Nemeth pioneered the discipline of UNIX system administration. She taught and mentored computer science students at the University of Colorado Boulder, was visiting faculty member at Dartmouth College and UC San Diego, and helped bring Internet technology to the developing world through her work with the Internet Society and the United Nations.

Garth Snyder has worked at NeXT and Sun and holds a BS in Engineering from Swarthmore College and an MD and an MBA from the University of Rochester.

Trent R. Hein (@trenthein) is a serial entrepreneur who is passionate about practical cybersecurity and automation. Outside of technology, he loves hiking, skiing, fly fishing, camping, bluegrass, dogs, and the Oxford comma. Trent holds a BS in Computer Science from the University of Colorado.

Ben Whaley is the founder of WhaleTech, an independent consultancy. He was honored by Amazon as one of the first AWS Community Heroes. He obtained a B.S. in Computer Science from the University of Colorado at Boulder.

Dan Mackin's (@dan_mackin) long-standing passion for technology inspired him to get a BS in Electrical and Computer Engineering from the University of Colorado at Boulder. He applies Linux and other open source technologies not only in his day job, but also to automation, monitoring, and weather metrics collection projects at home. Dan loves spending time with his wife and dog, skiing, movies, sailing, and backcountry touring.

Inhalt

Tribute to Evi xl

Preface xlii

Foreword xliv

Acknowledgments xlvi

Section One: Basic Administration 1

Chapter 1: Where to Start 3

Essential duties of a system administrator 4

Suggested background 7

Linux distributions 8

Example systems used in this book 9

Notation and typographical conventions 12

Units 13

Man pages and other on-line documentation 14

Other authoritative documentation 16

Other sources of information 18

Ways to find and install software 19

Where to host 25

Specialization and adjacent disciplines 26

Recommended reading28

Chapter 2: Booting and System Management Daemons 30

Boot process overview 30

System firmware 32

Boot loaders 35

GRUB: the GRand Unified Boot loader 35

The FreeBSD boot process 39

System management daemons .41

systemd in detail 44

FreeBSD init and startup scripts 57

Reboot and shutdown procedures 59

Stratagems for a nonbooting system 60

Chapter 3: Access Control and Rootly Powers 65

Standard UNIX access control 66

Management of the root account69

Extensions to the standard access control model 79

Modern access control 83

Recommended reading89

Chapter 4: Process Control 90

Components of a process 90

The life cycle of a process 93

ps: monitor processes 98

Interactive monitoring with top101

nice and renice: influence scheduling priority102

The /proc filesystem 104

strace and truss: trace signals and system calls 105

Runaway processes 107

Periodic processes109

Chapter 5: The Filesystem 120

Pathnames 122

Filesystem mounting and unmounting 122

Organization of the file tree125

File types 126

File attributes132

Access control lists 140

Chapter 6: Software Installation and Management 153

Operating system installation 154

Managing packages 162

Linux package management systems 164

High-level Linux package management systems 166

FreeBSD software management175

Software localization and configuration 178

Recommended reading 181

Chapter 7: Scripting and the Shell 182

Scripting philosophy 183

Shell basics 189

sh scripting 198

Regular expressions 209

Python programming 215

Ruby programming 223

Library and environment management for Python and Ruby 229

Revision control with Git 235

Recommended reading 241

Chapter 8: User Management 243

Account mechanics 244

The /etc/passwd file 245

The Linux /etc/shadow file250

FreeBSD's /etc/master.passwd and /etc/login.conf files 252

The /etc/group file 254

Manual steps for adding users 255

Scripts for adding users: useradd, adduser, and newusers 260

Safe removal of a user's account and files264

User login lockout265

Risk reduction with PAM 266

Centralized account management 266

Chapter 9: Cloud Computing 270

The cloud in context 271

Cloud platform choices 273

Cloud service fundamentals 276

Clouds: VPS quick start by platform283

Cost control 291

Recommended Reading 293

Chapter 10: Logging 294

Log locations296

The systemd journal 299

Syslog 302

Kernel and boot-time logging 318

Management and rotation of log files 319

Management of logs at scale 321

Logging policies 323

Chapter 11: Drivers and the Kernel 325

Kernel chores for system administrators 326

Kernel version numbering 327

Devices and their drivers 328

Linux kernel configuration339

FreeBSD kernel configuration 344

Loadable kernel modules 346

Booting 348

Booting alternate kernels in the cloud 355

Kernel errors356

Recommended reading 359

Chapter 12: Printing 360

CUPS printing 361

CUPS server administration 365

Troubleshooting tips 369

Recommended reading 371

Section Two: Networking 373

Chapter 13: TCP/IP Networking 375

TCP/IP and its relationship to the Internet 375

Networking basics 378

Packet addressing384

IP addresses: the gory details 387

Routing 398

IPv4 ARP and IPv6 neighbor discovery 401

DHCP: the Dynamic Host Configuration Protocol402

Security issues 406

Basic network configuration 410

Linux networking417

FreeBSD networking 425

Network troubleshooting 428

Network monitoring 437

Firewalls and NAT 440

Cloud networking448

Recommended reading 457

Chapter 14: Physical Networking 459

Ethernet: the Swiss Army knife of networking460

Wireless: Ethernet …