DevOps for the Desperate: A Hands-On Survival Guide

by Bradley Smith

Overview

DevOps for the Desperate is a hands-on, no-nonsense guide for those who land in a DevOps environment and need to get up and running quickly.

This book introduces fundamental concepts software developers need to know to flourish in a modern DevOps environment including infrastructure as code, configuration management, security, containerization and orchestration, monitoring and alerting, and troubleshooting. Readers will follow along with hands-on examples to learn how to tackle common DevOps tasks.
 
The book begins with an exploration of DevOps concepts using Vagrant and Ansible to build systems with repeatable and predictable states, including configuring a host with user-based security. Next up is a crash course on containerization, orchestration, and delivery using Docker, Kubernetes, and a CI/CDpipeline. The book concludes with a primer in monitoring and alerting with tips for troubleshootingcommon host and application issues.
 
You'll learn how to:

Use Ansible to manage users and groups, and enforce complex passwords

Create a security policy for administrative permissions, and automate a host-based firewall

Get started with Docker to containerize applications, use Kubernetes for orchestration, and deploycode using a CI/CD pipeline

Build a monitoring stack, investigate common metric patterns, and trigger alerts

Troubleshoot and analyze common issues and errors found on hosts

Product Details

ISBN-13:	9781718502499
Publisher:	No Starch Press
Publication date:	07/12/2022
Sold by:	Penguin Random House Publisher Services
Format:	eBook
Pages:	176
File size:	2 MB

About the Author

Bradley Smith is a Director of Infrastructure and resides in Denver, Colorado. He has been an engineer for more than 20 years at many startups and businesses of varying sizes. He's built and trained numerous DevOps, SRE, and software engineering teams. A Boston native, Bradley graduated from the University of Massachusetts Lowell.

Table of Contents

Acknowledgments xiv

Introduction xv

What is the Current State of DevOps? xvi

Who Should Read This Book? xvii

How This Book Is Organized xvii

Part I Infrastructure as Code, Configuration Management, Security, and Administration xvii

Part II Containerization and Deploying Modern Applications xviii

Part III Observability and Troubleshooting xviii

What You'll Need xviii

Downloading and Installing VirtualBox xx

Companion Repository xxi

Editor xxi

Part I Infrastructure as Code, Configuration Management, Security, and Administration 1

1 Setting Up a Virtual Machine 3

Why Use Code to Build Infrastructure? 3

Getting Started with Vagrant 4

Installation 4

Anatomy of a Vagrantfile 5

Basic Vagrant Commands 6

Getting Started with Ansible 6

Installation 7

Key Ansible Concepts 7

Ansible Playbook 8

Basic Ansible Commands 9

Creating an Ubuntu VM 9

Summary 11

2 Using Ansible to Manage Passwords, Users, and Groups 13

Enforcing Complex Passwords 14

Installing libpam-pwquality 14

Configuring pam_pwquality to Enforce a Stricter Password Policy 15

Linux User Types 16

Getting Started with the Ansible User Module 16

Generating a Complex Password 17

Linux Groups 18

Getting Started with the Ansible Group Module 18

Assigning a User to the Group 19

Creating Protected Resources 19

Updating the VM 20

Testing User and Group Permissions 21

Summary 23

3 Using Ansible to Configure SSH 25

Understanding and Activating Public Key Authentication 26

Generating a Public Key Pair 26

Using Ansible to Get Your Public Key on the VM 27

Adding Two-Factor Authentication 28

Installing Google Authenticator 29

Configuring Google Authenticator 29

Configuring PAM for Google Authenticator 30

Configuring the SSH Server 31

Restarting the SSH Server with a Handler 32

Provisioning the VM 33

Testing SSH Access 34

Summary 35

4 Controlling User Commands with Sudo 37

What Is sudo? 38

Planning a sudoers Security Policy 38

Installing the Greeting Web Application 39

Anatomy of a sudoers File 41

Creating the sudoers File 42

The sudoers Template 43

Provisioning the VM 44

Testing Permissions 45

Accessing the Web Application 45

Editing greeting.py to Test the sudoers Policy 46

Stopping and Starting with systemctl 46

Audit Lags 47

Summary 48

5 Automating and Testing a Host-Based Firewall 49

Planning the Firewall Rules 50

Automating UFW Rules 50

Provisioning the VM 53

Testing the Firewall 54

Scanning Ports with Nmap 55

Firewall Logging 56

Rate Limiting 57

Summary 58

Part II Containerization and Deploying Modern Applications 59

6 Containerizing an Application with Docker 61

Docker from 30,000 Feet 62

Getting Started with Docker 62

Dockerfile Instructions 63

Container Images and Layers 64

Containers 64

Namespaces and Cgroups 64

Installing and Testing Docker 65

Installing the Docker Engine with Minikube 65

Installing the Docker Client and Setting Up Docker Environment Variables 66

Testing the Docker Client Connectivity 66

Containerizing a Sample Application 66

Dissecting the Example telnet-server Dockerfile 67

Building the Container Image 68

Verifying the Docker Image 69

Running the Container 70

Other Docker Client Commands 71

Exec 71

Rm 72

Inspect 72

History 73

Stats 74

Testing the Container 74

Connecting to the Telnet-Server 74

Getting Logs from the Container 75

Summary 76

7 Orchestrating with Kubernetes 77

Kubernetes from 30,000 Feet 78

Kubernetes Workload Resources 79

Pods 79

ReplicaSet 79

Deployments 79

StatefulSets 80

Services 80

Volumes 80

Secrets 81

ConfigMaps 81

Namespaces 81

Deploying the Sample telnet-server Application 82

Interacting with Kubernetes 82

Reviewing the Manifests 82

Creating a Deployment and Services 87

Viewing the Deployment and Services 88

Testing the Deployment and Services 89

Accessing the Telnet Server 89

Troubleshooting Tips 91

Killing a Pod 92

Scaling 92

Logs 93

Summary 94

8 Deploying Code 95

CI/CD in Modern Application Stacks 96

Setting Up Your Pipeline 97

Reviewing the skaffold.yaml File 98

Reviewing the Container Tests 99

Simulating a Development Pipeline 100

Making a Code Change 102

Testing the Code Change 103

Testing a Rollback 104

Other CI/CD Tooling 105

Summary 106

Part III Observability and Troubleshooting 107

9 Observability 109

Monitoring Overview 110

Monitoring the Sample Application 111

Installing the Monitoring Stack 112

Verifying the Installation 113

Metrics 115

Golden Signals 115

Adjusting the Monitoring Pattern 115

The telnet-server Dashboard 116

PromQL: A Primer 118

Alerts 119

Reviewing Golden Signal Alerts in Prometheus 119

Routing and Notifications 121

Summary 123

10 Troubleshooting Hosts 125

Troubleshooting and Debugging: A Primer 126

Scenario: High Load Average 127

Uptime 127

Top 128

Next Steps 129

Scenario: High Memory Usage 129

Free 129

Vmstat 130

Ps 131

Next Steps 131

Scenario: High iowait 131

Iostat 132

Iotop 133

Next Steps 133

Scenario: Hostname Resolution Failure 133

Resolv.conf 134

Resolvectl 135

Dig 136

Next Steps 137

Scenario: Out of Disk Space 138

Df 138

Find 138

Isof 139

Next Steps 139

Scenario: Connection Refused 140

Curl 140

Ss 140

Tcpdump 141

Next Steps 142

Searching Logs 142

Common Logs 143

Common journals Commands 144

Parsing Logs 146

Probing Processes 148

Strace 148

Summary 151

Index 153

Editorial Reviews

"DevOps for the Desperate is a short, approachable guided tour of a few core tools in the software operations toolkit. Structured as a set of hands-on tutorials in topics like system administration basics, configuration tools like Ansible and Vagrant, and orchestration tools like Kubernetes, this book covers a lot of ground quickly. The focus is very much on the practical, rather than the philosophy of DevOps. Don't expect to use this as your sole reference on DevOps topics, but this is worthwhile as a gentle starting point for the absolute beginner to software operations."
—Laura Nolan, Slack

"A very useful book. . . . it would give any competent developer a good grasp of how to use the tools commonly found in DevOps. Recommended."
—Kay Ewbank, I-Programmer

"Zero-to-hero in one guide."
—td, Amazon Reviewer

From the Publisher