Jonathan Bartlett

Cloud Native Applications with Docker and Kubernetes

Design and Build Cloud Architecture and Applications with Microservices, EMQ, and Multi-Site Configurations

Jonathan Bartlett
Tulsa, OK, USA
ISBN 978-1-4842-8875-7e-ISBN 978-1-4842-8876-4
https://doi.org/10.1007/978-1-4842-8876-4
© Jonathan Bartlett 2023
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The registered company address is: 1 New York Plaza, New York, NY 10004, U.S.A.

Source Code

All source code used in this book is available to readers at github.com/apress/cloud-native-applications-docker-kubernetes.

Acknowledgments

There are a lot of people I would like to thank for this book. However, the most influential people that inspired this book were Clark Ritchie and Tyler Brown (and Chris Zenthoefer for introducing me to them). Both Clark and Tyler helped me to think more explicitly about clouds and cloud services and move my thinking from traditional forms of system administration and system architecture to more cloud native ways of thinking. I actually want to thank all my friends at Specialized Bicycles for the time I spent with them. You all were a great crew to work with, and I am extremely thankful for the time I spent with you all.

Table of Contents
Chapter 1:​ Introduction 1
1.​1 A Brief History of Web Service Hosting 1
1.​1.​1 The Old Way 1
1.​1.​2 The Virtual Private Server 2
1.​1.​3 From Virtual Private Servers to Containers 4
1.​1.​4 Cloud Native Infrastructure 5
1.​2 An Overview of This Book 7
1.​3 Prerequisites 7
1.​4 Typographical Conventions 8
Part I: An Introduction to Containers9
Chapter 2:​ Containers Under the Hood 11
2.​1 Answering Basic Questions About Containers 12
2.​1.​1 What Are Containers?​ 12
2.​1.​2 What Problems Do Containers Solve?​ 12
2.​1.​3 Does It Use a Lot of Disk Space?​ 13
2.​1.​4 What Is the Relationship Between “Docker” and “Containers”?​ 14
2.​2 A Short History of Container Technology 14
2.​2.​1 From Emulators to Virtual Machines 15
2.​2.​2 Increasing Isolation Inside the Operating System 16
2.​2.​3 The Birth of Containers 16
2.​2.​4 The Union Filesystem 17
2.​2.​5 The Rise of Docker 18
2.​3 Summary 20
Chapter 3:​ A Docker Interactive Tutorial 21
3.​1 Registries, Repositories, and Tags 21
3.​2 Running Your First Container 23
3.​3 Running a Docker Service 25
3.​4 Running a Whole Operating System 27
3.​5 Copying Files to and from the Container 27
3.​6 Creating a New Docker Image 28
3.​7 Creating Docker Images Using a Recipe 29
3.​8 Pushing the Image to Docker Hub 30
3.​9 Logging into a Running Docker Container 31
3.​10 Summary 31
Chapter 4:​ Best Practices for Building Containers 33
4.​1 How Not to Build a Container 34
4.​1.​1 Don’t Make a Container Perform Multiple Tasks 34
4.​1.​2 Don’t Include an Entire Operating System 35
4.​2 Base Images 37
4.​3 Alpine Distributions 38
4.​4 Avoid Bloated Images from Deleted Files 39
4.​5 Make Your Containers Configurable 40
4.​6 Be Clear About Your Statefulness 41
4.​7 Final Tips 42
4.​8 Summary 44
Part II: Introducing Kubernetes45
Chapter 5:​ The Cloud Native Philosophy 47
5.​1 Cloud-Level Operating System 47
5.​2 Declarative Infrastructure 48
5.​3 Containers Are “Cattle” Not “Pets” 50
5.​4 A Note on Costs 51
5.​5 Summary 52
Chapter 6:​ Getting Started with Kubernetes 53
6.​1 Setting Up Your First Cluster 53
6.​2 Deploying Your First Application 55
6.​3 Looking Around the Kubernetes Dashboard 58
6.​4 Summary 60
Chapter 7:​ Managing Kubernetes with kubectl 61
7.​1 Setting Up Your Connection 61
7.​2 Basic kubectl Commands 62
7.​3 Playing with kubectl 64
7.​4 Creating Another Deployment with kubectl 65
7.​5 Accessing Multiple Clusters 66
7.​6 Summary 67
Chapter 8:​ An Overview of the Kubernetes Environment 69
8.​1 Basic Kubernetes Components 69
8.​1.​1 The Control Plane 70
8.​1.​2 Nodes and Pods 71
8.​1.​3 Workloads 72
8.​1.​4 Kubernetes Services 72
8.​1.​5 CoreDNS 74
8.​1.​6 The Structure of a Pod 75
8.​2 Kubernetes Storage 77
8.​3 Configuring a Kubernetes Cluster 80
8.​4 Application Interaction with Kubernetes 81
8.​5 Summary 81
Chapter 9:​ Basic Kubernetes Management 83
9.​1 Infrastructure as Code 83
9.​2 A Short Introduction to YAML 85
9.​3 Defining Kubernetes Objects in YAML Manifest Files 87
9.​4 Kubernetes Files for Our Walkthrough Deployment 90
9.​4.​1 Organizing Your Kubernetes Files 92
9.​5 Deleting Kubernetes Objects 94
9.​6 Summary 95
Chapter 10:​ A Full Kubernetes Cloud Example 97
10.​1 The Application Code 99
10.​2 The Memcache Service 103
10.​3 The Database Service 105
10.​4 The Front-End Service 109
10.​5 The Message Board API Server 112
10.​6 Configurations and Secrets 116
10.​7 Making an Ingress 119
10.​8 Final Thoughts 122
10.​9 Summary 124
Chapter 11:​ Going Further in Kubernetes 125
11.​1 Cluster Namespaces 125
11.​2 Helm 127
11.​3 Capacity Management and Autoscaling 128
11.​4 DaemonSets 132
11.​5 Jobs 133
11.​6 Cluster Security 135
11.​7 Customizing Kubernetes 139
11.​8 Additional Information 140
11.​9 Summary 141
Part III: Architecting for the Cloud143
Chapter 12:​ A Cloud Architecture Introduction 145
12.​1 What Is Cloud Architecture?​ 145
12.​2 Architectural Diagrams 146
12.​3 Application Policies 148
12.​4 Summary 150
Chapter 13:​ Basic Cloud Architectures 153
13.​1 A Basic Load-Balanced Architecture 153
13.​2 Adding Caching to the Architecture 154
13.​3 An Ingress to Multiple Load-Balanced Systems 156
13.​4 Summary 158
Chapter 14:​ A Basic Microservice Architecture 159
14.​1 What Is a Microservice Architecture?​ 159
14.​2 Authentication and Authorization 160
14.​3 Choosing Where to Cut the Application 162
14.​4 URL Path Layout 162
14.​5 Quickly Transitioning to a Microservice Architecture 164
14.​6 Summary 166
Chapter 15:​ Enterprise Message Queues 167
15.​1 Basic Message Queue Components and Terminology 168
15.​2 Working with Work Queues 169
15.​3 Decoupling Systems with Publish/​Subscribe 171
15.​4 Event Bus Architecture 173
15.​5 Message Streaming for Permanent Replayability 175
15.​6 Two-Way Messaging 175
15.​7 The Job of the Cloud Architect 177
15.​8 Getting Started with Message Queueing 179
15.​9 Summary 181
Chapter 16:​ Architecting Data Stores 183
16.​1 Types of Data Stores 183
16.​1.​1 Relational Databases 184
16.​1.​2 Key/​Value Stores 185
16.​1.​3 Document Databases 186
16.​1.​4 Full-Text Databases 186
16.​1.​5 Object/​File Stores 187
16.​1.​6 Specialized Persistent Stores 187
16.​2 Implementing Stores Using a Relational Database 187
16.​2.​1 Document Databases 188
16.​2.​2 Full-Text Search 188
16.​2.​3 Object/​File Stores 190
16.​2.​4 Key/​Value Stores 191
16.​3 Database Topologies 191
16.​4 Database Partitioning 193
16.​5 Using UUIDs for Primary Keys 193
16.​6 Thinking About Sources of Truth 195
16.​7 Summary 196
Chapter 17:​ Extended Cloud Topologies 197
17.​1 Terminology 197
17.​2 How Kubernetes Handles Extended Topologies 199
17.​3 Considerations for Multiregion Deployments 200
17.​4 Summary 202
Chapter 18:​ Architecture Values 205
18.​1 Scalability 205
18.​2 Observability 207
18.​3 Traceability 207
18.​4 Testability 209
18.​5 Predictability 210
18.​6 Repeatability 211
18.​7 Integrity and Security 212
18.​8 Summary 215
Chapter 19:​ Conclusion 217
Appendix A:​ Navigating the Linux Command-Line Shell 219
Appendix B:​ Installing Applications 231
Appendix C:​ Common kubectl Commands 235
Appendix D:​ More on Kubernetes Storage 243
Appendix E:​ More on Pod Scheduling 251
Appendix F:​ Troubleshooting Kubernetes Clusters 257
Index 263
About the Author
Jonathan Bartlett

A photo of Jonathan Bartlett.

is a senior software developer at McElroy Manufacturing. His career has had a primary focus on developing data models and web APIs for both internally and externally facing business applications. He has worked with a large variety of languages, platforms, and development styles in his more than 20 years of experience in the industry.

Jonathan has been educating programmers for well over a decade. His first book, Programming from the Ground Up, is an Internet classic and was endorsed by Joel Spolsky, cofounder of StackExchange. It was one of the first open source books and has been used by a generation of programmers to learn how computers work from the inside out, using assembly language as a starting point. After more than 15 years, Programming from the Group Up was recently updated and rereleased as Learn to Program with Assembly: Foundational Learning for New Programmers.

Recently, Jonathan released Programming for Absolute Beginners which is focused on teaching brand new programmers about computers, the Internet, and JavaScript programming, based on his experience teaching programming to high-school and college students. Additionally, Jonathan has written several books on the interplay of philosophy, math, and science, including Calculus from the Ground Up, Engineering and the Ultimate, and Naturalism and Its Alternatives in Scientific Methodologies. For those interested in the more physical aspects of computing, he wrote Electronics for Beginners.

Jonathan also writes developer-focused articles for a number of technology websites. He is currently a writer for the technology blog MindMatters, and you can find his articles at https://mindmatters.ai/author/jbartlett . He has also written for IBM’s DeveloperWorks, Linux.com, Medium.com, and Classical Conversations.

Jonathan also participates in a variety of academic work. He is an associate fellow of the Walter Bradley Center for Natural and Artificial Intelligence. There he does research into fundamental mathematics and the mathematics of artificial intelligence. He also serves on the editorial board for the journal Bio-Complexity, focusing on reviewing information-theoretic papers for the journal. Jonathan also served as editor of the book Controllability of Dynamic Systems: The Green’s Function Approach, which received the RA Presidential Award of the Republic of Armenia in the area of technical sciences and information technologies. Jonathan also spends time teaching at a homeschool co-op through Classical Conversations.

Jonathan is married to his wife Christa. They have been together for over 20 years and have had five children.

 
About the Technical Reviewer
Shivakumar R. Goniwada

A photo of Shivakumar R. Goniwada.

is a chief enterprise architect, technology leader, and inventor with more than 24 years of experience focusing on Cloud Native Elements, Enterprise Architecture Setup, and Big Transformation Projects. He currently works at Accenture and leads a highly experienced technology enterprise and cloud architects. In his 24 years of experience, he has led many highly complex projects across industries and geographic regions. He has ten software patents to his name in the areas of cloud, microservices architecture, software engineering, and IoT (a few yet to publish). He has been a speaker at multiple global and in-house conferences. He holds Master Technology Architecture Accenture, Google Professional, AWS, and data science certifications. His executive MBA is from the MIT Sloan School of Management.

 
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