Linux Administration SBL c otein Best Practices t Astu la x nP Linux MrA illeacdm rt Linux is a well-known, open source Unix-family operating system that is the most widely used i ci n Administration OS today. Linux looks set for a bright future for decades to come, but system administration is e i ss rarely studied beyond learning rote tasks or following vendor guidelines. To truly excel at Linux t r administration, you need to understand how these systems work and learn to make strategic a decisions regarding them. t Best Practices i o Linux Administration Best Practices helps you to explore best practices for effi ciently administering n Linux systems and servers. This Linux book covers a wide variety of topics, from installation and deployment through to managing permissions, with each topic beginning with an overview of the key concepts followed by practical examples of best practices and solutions. You'll fi nd out how to approach system administration, Linux, and IT in general, put technology into proper business Practical solutions to approaching the design and context, and rethink your approach to technical decision making. Finally, the book concludes by helping you to understand best practices for troubleshooting Linux systems and servers that'll management of Linux systems enable you to grow in your career as well as in any aspect of IT and business. By the end of this Linux administration book, you'll have gained the knowledge needed to take your Linux administration skills to the next level. Things you will learn: • Find out how to conceptualize the • Understand the reasoning behind system administrator role system administration best practices • Understand the key values of risk • Develop out-of-the-box thinking for assessment in administration everything from reboots to backups • Apply technical skills to the IT to triage business context • Prioritize, triage, and plan for disasters • Discover best practices for working with and recoveries Linux-specifi c system technologies • Discover the psychology behind administration duties Scott Alan Miller Linux Administration Best Practices Practical solutions to approaching the design and management of Linux systems Scott Alan Miller BIRMINGHAM—MUMBAI Linux Administration Best Practices Copyright © 2022 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. Group Product Manager: Rahul Nair Publishing Product Manager: Rahul Nair Senior Editor: Shazeen Iqbal Content Development Editor: Rafiaa Khan Technical Editor: Arjun Varma Copy Editor: Safis Editing Project Coordinator: Shagun Saini Proofreader: Safis Editing Indexer: Manju Arasan Production Designer: Aparna Bhagat Marketing Coordinator: Hemangi Lotlikar First published: February 2022 Production reference: 1120122 Published by Packt Publishing Ltd. Livery Place 35 Livery Street Birmingham B3 2PB, UK. ISBN 978-1-80056-879-2 www.packt.com To my father, who had the wherewithal and foresight to introduce me to programming and computers at a very young age and taught me to see technology as a business tool. And to my wife, Dominica, and my daughters, Liesl and Luciana, for suffering through the writing of a book on top of all of the normal craziness that life is always throwing at us. My team makes this all possible. – Scott Alan Miller Contributors About the author Scott Alan Miller is an information technology and software engineering industry veteran of 30+ years, with more than a quarter of a century on UNIX and Linux. His experience has included companies of every size, in every region of the world, in nearly every industry. Scott has been a technician, lead, manager, educator, consultant, writer, author, speaker, and mentor. Today, and for more than the last 20 years, Scott has led the IT consulting team at NTG. He now lives in Nicaragua. About the reviewer René Jensen has 21 years of professional experience with UNIX/Linux administration, both as an employed administrator and, for the last 9 years, as a consultant. His experience ranges from branches such as medical, banking, tax, and mobile business, to working in areas such as CI/CD, container deployment, architecting server clusters, daily operations, and many other areas. I would like to thank my family for being patient, since my work started as a hobby and I spend a lot of time going in depth with new challenges. Table of Contents Preface Section 1: Understanding the Role of Linux System Administrator 1 What Is the Role of a System Administrator? Where are system Getting family and friends involved 17 administrators in the real world? 4 Start as a generalist and progress Wearing the administrator and onto a specialist in the System Administrator field 18 engineering hats 6 Volunteer for non-profits or non- The difference between the role of business organizations 18 an administrator and the role of Self-study 19 an engineer 7 Age does not matter 20 Hats 7 Internships 21 The wonderous variety of the role 12 Introducing the IT Professional 22 Understanding systems in the business ecosystem 14 The fallacy of success at any cost 25 Learning system administration 16 Summary 25 Build a home lab 16 2 Choosing Your Distribution and Release Model Understanding Linux in Linux licensing 30 production 28 Key vendors and products 33 Is Linux UNIX? 29 What about BSD? 33 viii Table of Contents Debian 35 Release model: rapid release 49 Ubuntu 35 Release model: LTS 50 IBM Red Hat Enterprise Linux (RHEL) 36 Release and support schedule RHEL alternatives 37 interplay: The overlap 52 Fedora 38 Release model: Rolling 53 OpenSUSE and SLES 38 Why not just update the packages Digging into distribution history 39 manually 54 Other Linux distributions 40 Choosing the release model for our workloads 56 The myth of popularity 41 Choosing your distribution 58 Using multiple distributions 42 Do not fear risk 59 Making the choice 43 Summary 60 Releases and support: LTS, current, and rolling 45 What does support mean? 47 Section 2: Best Practices for Linux Technologies 3 System Storage Best Practices Exploring key factors in storage 64 EXT4 77 Cost 64 XFS 77 Durability 65 ZFS 78 Availability 65 BtrFS 79 Performance 66 Clustered file systems 80 Scalability 67 Network filesystems 81 Capacity 68 Getting to know logical volume Understanding block storage: management (LVM) 84 Local and SAN 68 Whatever happen to partitions 85 Locally attached block storage 69 Utilizing RAID and RAIN 87 Storage Area Networks (SAN) 69 RAID 87 The terrible terminology of SAN 69 RAIN 88 Surveying filesystems and network filesystems 74 Table of Contents ix Learning about replicated local General storage architectures 96 storage 90 Simple local storage: The brick 96 DRBD 91 RLS: The ultra-high reliability solution 99 Gluster and CEPH 92 The lab environment: Remote shared Proprietary and third-party open- standard storage 100 source solutions 93 The giant scale: Remote replicated Virtualization abstraction of storage 93 storage 101 Storage best practices 103 Analyzing storage architectures and risk 95 Storage example 104 Summary 109 4 Designing System Deployment Architectures Virtualization 112 System Design Architecture 136 Type 1 hypervisor 113 Standalone server, aka the snowflake 136 Type 2 hypervisor 113 Simple does not necessarily Hypervisor types are confusing 115 mean simple 138 VMware ESXi 116 Many to many servers and storage 139 Microsoft Hyper-V 116 Viewing the world as a workload 140 Xen 116 Layered high availability 143 KVM 117 Reliability is relative 144 Is virtualization only for consolidation? 117 Hyperconvergence 145 Best practices in System Design Containerization 119 Architecture 146 Cloud and VPS 122 Risk assessment and availability needs 147 Virtual Private Servers (VPS) 130 Workload interplay 149 Defining high availability 151 On premises, hosted, and hybrid hosting 133 Summary 154 Colocation 134 5 Patch Management Strategies Binary, source, and script Misleading use of source installation 160 software deployments 158 Patching theory and strategies 165 Compiled and interpreted software 158 The risk of delayed patching 166