Table Of ContentTHE KUBERNETES
BIBLE
The definitive guide to deploying and managing
Kubernetes across major cloud platforms
Nassim Kebbani
Piotr Tylenda
Russ McKendrick
BIRMINGHAM—MUMBAI
THE KUBERNETES BIBLE
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 authors, 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: Shrilekha Malpani
Senior Editor: Athikho Sapuni Rishana
Content Development Editor: Nihar Kapadia
Technical Editor: Shruthi Shetty
Copy Editor: Safis Editing
Project Coordinator: Neil D'mello
Proofreader: Safis Editing
Indexer: Tejal Daruwale Soni
Production Designer: Alishon Mendonca
Marketing Coordinator: Sanjana Gupta
First published: February 2022
Production reference: 1130122
Published by Packt Publishing Ltd.
Livery Place
35 Livery Street
Birmingham
B3 2PB, UK.
ISBN 978-1-83882-769-4
www.packt.com
Contributors
About the authors
Nassim Kebbani is an experienced software engineer with in-depth expertise in
Kubernetes and the Amazon Web Services cloud provider. He has an extensive
background both in software development and operations teams, having implemented
the entire spectrum of a DevOps life cycle chain, from application code to pipelines,
and carried out monitoring in various industries such as e-commerce, media, and
financial services.
He has implemented numerous cloud-native architectures and containerized applications
on Docker and AWS and holds both Kubernetes CKA and CKAD certifications.
Piotr Tylenda is an experienced DevOps and software engineer with a passion for
Kubernetes and Azure technologies. In his projects, he has focused on the adoption of
microservices architecture for monolithic applications, developing big data pipelines
for e-commerce, and architecting solutions for scalable log and telemetry analytics for
hardware. His most notable contribution to Kubernetes' open source ecosystem is the
development of Ansible automation for provisioning and deploying hybrid Windows/
Linux Kubernetes clusters. Currently, he works at Microsoft Development Center
Copenhagen in Denmark as part of a team developing a Microsoft Dynamics 365 Business
Central SaaS offering.
Russ McKendrick is an experienced DevOps practitioner and system administrator with
a passion for automation and containers. He has been working in IT and related industries
for the better part of 27 years. During his career, he has had varied responsibilities in
many different sectors, including first-line, second-line, and senior support in both client-
facing and internal teams for small and large organizations. He works almost exclusively
with Linux, using open source systems and tools across both dedicated hardware and
virtual machines hosted in public and private clouds at N4Stack, which is a Node4
company, where he holds the title of practice manager (SRE and DevOps). He also buys
way too many records!
About the reviewer
Dushyant Nathalal Dubaria pursued a Master of Science degree in network and
telecommunication engineering from Southern Methodist University, USA, in December
2019. He is passionate about DevOps, the cloud, networking, virtualization, and
automation, and has a keen interest in technologies such as Docker and Kubernetes.
He has published articles in three international journal publications in IEEE, held at
Columbia University, New York, and at the University of Nevada, Las Vegas. He was
a teaching assistant and lecturer at Southern Methodist University and loves teaching
DevOps for networking, network automation, and programmability to graduate students.
He likes contributing to open source projects and was a speaker at the Linux Foundation
Event: Open Networking Summit, San Jose, April 2019, and at the Open Source Summit,
San Diego, August 2019.
Reviewing a book is harder than I thought and more rewarding than I
could have ever imagined. I would like to thank my friend, Jay Ashok Shah,
who introduced me to the world of DevOps and Kubernetes.
To my caring parents for always encouraging me to accomplish my goals.
To my loving wife, Monika, for her continued support with everything I do.
Finally, my sincere appreciation to the Packt committee for the learning
opportunities they have afforded me, especially Kajol Pawar and Neil
D'mello.
Table of Contents
Preface
Section 1: Introducing Kubernetes
1
Kubernetes Fundamentals
Understanding monoliths How can Kubernetes help
and microservices 4 you to manage your
Docker containers? 16
Understanding the growth of the
internet since the late 1990s 4 Understanding that Kubernetes is
Understanding the need for more meant to use Docker in production 16
frequent software releases 5
Exploring the problems that
Understanding the organizational shift
Kubernetes solves 18
to agile methodologies 5
Understanding the shift from Ensuring high availability 18
on-premises to the cloud 7 Release management and
Understanding why the cloud is well container deployment 19
suited for scalability 8 Autoscaling containers 21
Exploring the monolithic architecture 10 When and where is Kubernetes
Exploring the microservices architecture 10 not the solution? 22
Choosing between monolithic and
Understanding the history
microservices architectures 12
of Kubernetes 22
Understanding containers Understanding how and where
and Docker 13 Kubernetes started 22
Understanding why Docker is good Who manages Kubernetes today? 24
for microservices 13 Where is Kubernetes today? 24
Understanding the benefit of Docker
Summary 25
container isolation 14
vi Table of Contents
2
Kubernetes Architecture – From Docker Images to
Running Pods
Understanding the difference The Kubelet and worker
between the master and node components 53
worker nodes 28
The Kubelet agent 54
The kube-apiserver component 34 The kube-proxy component 56
The role of kube-apiserver 34
The kube-scheduler component 56
How do you install kube-apiserver? 38
The role of the kube-scheduler
Where do you install kube-apiserver? 40
component 56
Exploring the kubectl Where do you install kube-scheduler? 58
command-line tool
The kube-controller-manager
and YAML syntax 42
component 58
The role of kubectl 42
The role of the kube-controller-
How does kubectl work? 44
manager component 59
The YAML syntax 46
Where do you install
kubectl should be installed on any
kube-controller-manager? 59
machine that needs to interact with
the cluster 49 How to make Kubernetes
highly available 60
The Etcd datastore 50
The single-node cluster 60
The role of the Etcd datastore 50
The single-master cluster 61
Where do you install Etcd? 52
The multi-master multi-node cluster 62
Summary 64
3
Installing Your First Kubernetes Cluster
Technical requirements 66 Launching a multi-node
Installing a single-node cluster Kubernetes cluster with Kind 71
with Minikube 67 Installing Kind onto your local system 72
Launching a single-node Kubernetes Stopping and deleting the local
cluster using Minikube 67 Kind cluster 74
Stopping and deleting the local
Installing a Kubernetes cluster
Minikube cluster 70
using Google GKE 75
Table of Contents vii
Launching a multi-node Kubernetes Deleting the Kubernetes cluster on
cluster on Google GKE 76 Amazon EKS 88
Stopping and deleting a Kubernetes
Installing a Kubernetes cluster
cluster on Google GKE 80
using Azure AKS 89
Installing a Kubernetes cluster
Launching a multi-node Kubernetes
using Amazon EKS 80 cluster on Azure AKS 89
Launching a multi-node Kubernetes Stopping and deleting a Kubernetes
cluster on Amazon EKS 81 cluster on Azure AKS 92
Summary 92
Section 2: Diving into Kubernetes
Core Concepts
4
Running Your Docker Containers
Technical requirements 96 What are labels and why do we
need them? 108
Let's explain the notion of Pods 97
What are annotations and how do they
Each Pod gets an IP address 99
differ from labels? 109
How you should design your Pods 100
Adding a label 109
Launching your first Pods 101 Listing labels attached to a Pod 111
Adding or updating a label to/of a
Creating a Pod with imperative syntax 101
running Pod 111
Creating a Pod with declarative syntax 102
Deleting a label attached to a
Reading the Pod's information
running Pod 112
and metadata 103
Adding an annotation 113
Listing the objects in JSON or YAML 104
Backing up your resource using the Launching your first job 113
list operation 104
What are jobs? 114
Getting more information from the
Creating a job with restartPolicy 115
list operation 105
Understanding the job's backoffLimit 116
Accessing a Pod from the outside world 105
Running a task multiple times
Entering a container inside a Pod 106
using completions 117
Deleting a Pod 107
Running a task multiple times
Labeling and annotating in parallel 118
the Pods 107
viii Table of Contents
Terminating a job after a specific Understanding the role of the
amount of time 119 jobTemplate section 124
What happens if a job succeeds? 120 Controlling the Cronjob
Deleting a job 120 execution deadline 124
Managing the history limits of jobs 124
Launching your first Cronjob 121
Creating a Cronjob 125
What are Cronjobs? 121 Deleting a Cronjob 125
Creating your first Cronjob 122
Summary 125
Understanding the schedule 123
5
Using Multi-Container Pods and Design Patterns
Technical requirements 128 Sharing volumes between
Understanding what containers in the same Pod 144
multi-container Pods are 128 What are Kubernetes volumes? 145
Concrete scenarios where you need Creating and mounting an
multi-container Pods 129 emptyDir volume 147
When not to create a Creating and mounting a
multi-container Pod 130 hostPath volume 150
Creating a Pod made up of
The ambassador design pattern 152
two containers 130
What is the ambassador
What happens when Kubernetes fails
design pattern? 152
to launch one container in a Pod? 132
A simple example of an ambassador
Deleting a multi-container Pod 135
multi-container Pod 153
Understanding the Pod deletion
grace period 136 The sidecar design pattern 154
Accessing a specific container inside
What is the sidecar design pattern? 155
a multi-container Pod 137
A simple example of a sidecar multi-
Running commands in containers 138
container Pod 155
Overriding the default commands run
by your containers 139 The adapter design pattern 155
Introducing initContainers 141 What is the adapter design pattern? 156
Accessing the logs of a A simple example of an adapter multi-
specific container 143 container Pod 156
Summary 157
Table of Contents ix
6
Configuring Your Pods Using ConfigMaps and Secrets
Technical requirements 160 Mounting a ConfigMap as a
volume mount 175
Understanding what
ConfigMaps and Secrets are 160 Deleting a ConfigMap 177
Updating a ConfigMap 178
Decoupling your application and
your configuration 161 Managing sensitive
Understanding how Pods consume configuration with the
ConfigMaps and Secrets 163 Secret object 178
Configuring your Pods Listing Secrets 178
using ConfigMaps 164 Creating a Secret imperatively with
--from-literal 179
Listing ConfigMaps 164
Creating a Secret declaratively with a
Creating a ConfigMap 164
YAML file 179
Creating a ConfigMap from
Creating a Secret with content
literal values 166
from a file 180
Storing entire configuration files
Reading a Secret 181
in a ConfigMap 167
Consuming a Secret as an
Creating a ConfigMap from an env file 169
environment variable 182
Reading values inside a ConfigMap 170
Consuming a Secret as a volume mount 183
Linking ConfigMaps as
Deleting a Secret 184
environment variables 172
Updating a Secret 184
Summary 185
7
Exposing Your Pods with Services
Technical requirements 188 Understanding round-robin load
balancing in Kubernetes 193
Why would you want to expose
your Pods? 188 Understanding how to call a service
in Kubernetes 194
Understanding Pod IP assignment 188
Understanding how DNS names are
Understanding Pod IP assignment
generated for services 194
is dynamic 190
How services get a list of the Pods they
Never hardcode a pod's IP addresses
service traffic to 195
in your application code 191
Using the dnsutils Docker image to
Understanding how services route
debug your services 197
traffic to Pods 192
Why you shouldn't use the --expose flag 199
