Quick Start Kubernetes

101 Pages·2022·17.136 MB·English

by  Nigel Poulton

Quick Start Kubernetes
Nigel Poulton
Thisbookisforsaleathttp://leanpub.com/quickstartkubernetes
Thisversionwaspublishedon2022-01-19
ThisisaLeanpubbook.Leanpubempowersauthorsandpublisherswiththe
LeanPublishingprocess.LeanPublishingistheactofpublishinganin-progress
ebookusinglightweighttoolsandmanyiterationstogetreaderfeedback,pivot
untilyouhavetherightbookandbuildtractiononceyoudo.
©2021-2022NigelPoulton
Contents
Abouttheauthor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
NigelPoulton(@nigelpoulton) . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Aboutthebook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Whoisthebookfor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Whatdoesthebookcover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
WillthebookmakeyouaKubernetesexpert . . . . . . . . . . . . . . . . . . 2
Willyouknowwhatyou’retalkingaboutwhenyoufinishthebook . . . 3
Editions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Terminologyandresponsiblelanguage . . . . . . . . . . . . . . . . . . . . . . 3
Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Thesampleapp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1:WhatisKubernetes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Whataremicroservices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Whatiscloud-native. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Whatisanorchestrator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
OtherusefulKubernetesstufftoknow . . . . . . . . . . . . . . . . . . . . . . 12
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2:WhyweneedKubernetes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
WhytechcompaniesneedKubernetes . . . . . . . . . . . . . . . . . . . . . . 15
WhytheusercommunityneedsKubernetes . . . . . . . . . . . . . . . . . . . 17
ChapterSummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3:WhatdoesKuberneteslooklike . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Controlplanenodesandworkernodes . . . . . . . . . . . . . . . . . . . . . . 20
Controlplanenodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Workernodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
CONTENTS
HostedKubernetes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
ManagingKuberneteswiththekubectlcommandlinetool . . . . . . . . . 26
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4:GettingKubernetes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
KubernetesonyourlaptopwithDockerDesktop . . . . . . . . . . . . . . . 27
KubernetesinthecloudwithLinodeKubernetesEngine(LKE) . . . . . . 29
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
5:Creatingacontainerizedapp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Pre-requisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Gettheapplicationcode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Buildthecontainerimage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Hosttheimageonaregistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
6:RunninganapponKubernetes . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
VerifyyourKubernetescluster . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
DeploytheapptoKubernetes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Connecttotheapp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Clean-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
7:Addingself-healing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
IntrotoKubernetesDeployments . . . . . . . . . . . . . . . . . . . . . . . . . 59
Self-healfromaPodfailure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Self-healfromaworkernodefailure . . . . . . . . . . . . . . . . . . . . . . . 64
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
8:Scalingtheapp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Pre-requisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Scaleanapplicationup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
Scaleanapplicationdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Anotherwordonlabels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Importantclean-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
9:Performingarollingupdate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Pre-requisites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Updatetheapp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
CONTENTS
Clean-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Chaptersummary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
10:Whatnext . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Otherbooks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Videocourses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Let’sconnect. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Showsomelove. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
AppendixA:Labcode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Chapter5:Creatingacontainerizedapp . . . . . . . . . . . . . . . . . . . . . 85
Chapter6:RunninganapponKubernetes . . . . . . . . . . . . . . . . . . . . 86
Chapter7:Addingself-healing . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Chapter8:Scalinganapp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
Chapter9:Performingarollingupdate . . . . . . . . . . . . . . . . . . . . . . 91
Terminology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
About the author
Nigel Poulton (@nigelpoulton)
Hi, I’m Nigel. I live in the UK and I’m a techoholic. In fact, working with
technologieslikethecloudandcontainersislivingthedreamforme!
My early career was massively influenced by a book called Mastering Windows
Server2000byMarkMinasi.Eversincereadingit,Iwantedtowritemyownbooks
so I could influence people’s lives and careers the way Mark’s book influenced
mine.Sincethen,I’vebeenfortunateenoughtoauthorseveralbest-sellingbooks,
including Data Storage Networking, Docker Deep Dive, and The Kubernetes Book. I
feel so privileged to have reached so many people and genuinely appreciate the
feedbackIreceive.
I’m also the author of best-selling video training courses on Docker and Kuber-
netes.Myvideosarealwaysentertaining,andoccasionallylaugh-out-loudfunny
(notmywords).
Seeafulllistofmyvideosathttps://nigelpoulton.com/video-courses
At my website, nigelpoulton.com, you’ll also find all my books, my blog, weekly
newsletter,andotherthingsthatI’mdoing.
WhenI’mnotworkingwithcontainersandKubernetes,I’mdreamingaboutthem.
WhenI’mnotdreamingaboutthem,I’mspendingtimewithmyfamily.Ialsolike
Americanmusclecars,playinggolf,readingsci-fi,andIsupportSunderlandAFC
(thegreatestfootball/soccerteamintheworld).
I’mhappytoconnectandI’malwayslookingforwaystoimprovemybooksand
videos.Thesearesomeoftheeasiestwaystogetconnected.
• twitter.com/nigelpoulton
• linkedin.com/in/nigelpoulton/
• nigelpoulton.com
• [e-mail]
About the book
As the title states, this is a quick start guide to Kubernetes. It doesn’t cover
everything, just the important bits. And it covers them as clearly as possible in
anengagingway.It’salsoagreatmixoftheoryandoptionalhands-on.
ThegoalistodemystifyKubernetesandgetyousomehands-onexperience.
Who is the book for
Iwrotethebookforanyoneandeveryonethatneedstogetup-to-speedwiththe
fundamentalsofKubernetesandlikestolearnbydoing.
Theentirebook,theoryandlabs,havebeenhand-craftedovermanyyearssothat
technicalandnon-technicalreaderswillbenefitequally.So,whetheryouworkin
marketing,management,architecture,oroneofthemanyhands-onroles,you’re
goingtolovethebook.
What does the book cover
You’lllearnwhywehaveKubernetes,whatitis,andwhereit’sgoing.
Onthe theory front,you’lllearn about microservices,orchestration,whyKuber-
netesistheOSofthecloud,andthearchitectureofaKubernetescluster.Onthe
hands-on front, you’ll have the opportunity to build a cluster, containerize an
app,deployit,breakit,seeKubernetesfixit,scaleit,andperformanapplication
update.
Andasthisisaquickstartguide,you’llbeup-to-speedinnotimeatall.
Will the book make you a Kubernetes expert
No,butitwillstartyouonyourjourneytobecominganexpert.
Aboutthebook 3
Will you know what you’re talking about when
you finish the book
Yes, you’ll be able to hold your own in conversations about Kubernetes at the
coffeemachineandwithyourpeers.
Editions
ThefollowingEnglishlanguageeditionsareavailableinasmanyAmazonterrito-
riesaspossible:
• Hardback
• Paperback
• Kindle
EbookcopiesarealsoavailablefromLeanpub.com
ThefollowingtranslationsareavailableonAmazonandLeanpub(orwillbevery
soon).
• French, German, Hindi, Italian, Portuguese, Russian, Simplified Chinese,
Spanish.
Terminology and responsible language
ThroughoutthebookIcapitalizeKubernetesAPIobjects.Wow,wehaven’teven
startedandI’mthrowingjargonaround:-D
Put more simply, Kubernetes features such as Pods and Services are spelled with
a capital letter. This helps you know when I’m talking about a Kubernetes “Pod”
andnota“pod”ofwhales.
ThebookalsofollowsguidelinesfromtheInclusiveNamingInitiative(inclusive-
naming.org) which promotes responsible language. As an example, the Kuber-
netes project has replaced the potentially harmful term “master” with “control
plane node”. This book does the same and attempts to follow all guidance from
theinclusivenaminginitiative.
Aboutthebook 4
Feedback
Ifyoulikethebookandit’shelpedyourcareer,sharethelovebyrecommending
ittoafriendandleavingareviewonAmazon.
ModernbooksliveanddiebyAmazonreviewsandstars,soI’dbegratefulifyou
couldwriteone.YoucansometimesleaveanAmazonreviewevenifyougotthe
bookfromsomewhereelse.
[e-mail].
The sample app
Asthisisahands-onbook,ithasasampleapp.
It’sasimpleNode.jsappavailableonGitHubat:
https://github.com/nigelpoulton/qsk-book/
Don’t stress about the app and GitHub if you’re not a developer. The focus of
thebookisKubernetes,nottheapp.Plus,weexplaineverythinginlaymanterms
whentalkingabouttheapp,andyoudon’thavetoknowhowtouseGitHub.
If you’re interested, the code for the app is in the App folder and comprises the
followingfiles.
• app.js:Thisisthemainapplicationfile.It’saNode.jswebapp.
• bootstrap.css:Thisisadesigntemplatefortheapplication’swebpage.
• package.json:Thisfilelistsanydependenciestheapphas.
• views:Thisisafolderforthecontentsoftheapplication’swebpage.
• Dockerfile:ThisfiletellsDockerhowtobuildtheappintoacontainer.
If want to download the app now, run the following command. You’ll need git
installedonyourmachine.It’sOKifyoudon’thavegit,weshowyouhowtoget
itanddownloadtheapplaterinthebook.
$ git clone https://github.com/nigelpoulton/qsk-book.git
$ cd qsk-book
Finally,theappischeckedatleastonceperyearforpackageupdatesandknown
vulnerabilities.