Kubernetes 101 PDF
Preview Kubernetes 101
Kubernetes 101 Learn the basics of Kubernetes and container-based infrastructure. Jeff Geerling and Katherine Geerling Thisbookisforsaleathttp://leanpub.com/kubernetes-101 Thisversionwaspublishedon2021-07-29 ThisisaLeanpubbook.Leanpubempowersauthorsand publisherswiththeLeanPublishingprocess.Lean Publishingistheactofpublishinganin-progressebook usinglightweighttoolsandmanyiterationstogetreader feedback,pivotuntilyouhavetherightbookandbuild tractiononceyoudo. ©2021JeffGeerlingandKatherineGeerling Tweet This Book! PleasehelpJeffGeerlingandKatherineGeerlingby spreadingthewordaboutthisbookonTwitter! Thesuggestedtweetforthisbookis: IjustboughtKubernetes101byJeffGeerlingonLeanPub! Checkitoutathttps://leanpub.com/kubernetes-101 #Kube101 Thesuggestedhashtagforthisbookis#kube101. Findoutwhatotherpeoplearesayingaboutthebookby clickingonthislinktosearchforthishashtagonTwitter: #kube101 Also By Jeff Geerling AnsibleforDevOps AnsibleforKubernetes Contents Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i Whoisthisbookfor? . . . . . . . . . . . . . . . . . . ii Typographicconventions . . . . . . . . . . . . . . . . ii Pleasehelpimprovethisbook! . . . . . . . . . . . . . iv CurrentPublishedBookVersionInformation . iv AbouttheAuthor. . . . . . . . . . . . . . . . . . . . . iv Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . v ExamplesRepository . . . . . . . . . . . . . . . . . . . viii Otherresources . . . . . . . . . . . . . . . . . . . . . . ix Chapter1-Hello,Kubernetes! . . . . . . . . . . . . . . 1 KubernetesOrigins . . . . . . . . . . . . . . . . . . . . 1 IsKubernetesRightforYou? . . . . . . . . . . . . . . 3 KubernetesEnvironments . . . . . . . . . . . . . . . 5 InstructionsforMinikube . . . . . . . . . . . . . . . . 6 BuildingtheexampleDockerimage . . . . . . . . . 8 Chapter2-Containers . . . . . . . . . . . . . . . . . . . 10 WhydoesKubernetesusecontainers? . . . . . . . . 10 ContainerHistory:VendorWars . . . . . . . . . . . 11 Docker,containerd,andrunC . . . . . . . . . . 12 rktandCoreOS . . . . . . . . . . . . . . . . . . . 14 KubernetesContainerRuntime . . . . . . . . . 14 CONTENTS CRI-O . . . . . . . . . . . . . . . . . . . . . . . . . 14 ModernContainerRuntimeoptions. . . . . . . 15 Howdoyoubuildacontainer?DockervsBuildah 15 Instructionsfor‘HelloGo’app . . . . . . . . . . . . . 16 Buildthe‘HelloGo’Dockercontainerimage . . . . 17 PushthecontainerimagetoaprivateDockerregistry 17 Chapter3-Deployingapps . . . . . . . . . . . . . . . . 19 CreatingaLinodeClusterforcloud-basedtesting . 19 DeployingHelloGointoKubernetes . . . . . . . . . 21 ExposingtheHelloGoApp. . . . . . . . . . . . . . . 24 ScalingtheHelloGoApp . . . . . . . . . . . . . . . . 26 UpdatingtheGoApp . . . . . . . . . . . . . . . . . . 28 RollingbacktheDeployment . . . . . . . . . . . . . 29 Chapter4-Real-worldapps . . . . . . . . . . . . . . . . 30 InstallingDrupalonaTraditionalLAMPserver . . 30 LAMPServerSetupfordrupal . . . . . . . . . . 31 AutomatingtheInstallation . . . . . . . . . . . . . . 34 Installing Drupal on Kubernetes using Bitnami’s HelmChart . . . . . . . . . . . . . . . . . . . . 35 InstallHelm . . . . . . . . . . . . . . . . . . . . . 36 InstalltheDrupalChart . . . . . . . . . . . . . . 36 ExposingaLoadBalancerinMinikube . . . . . 37 ChangingChartOptions . . . . . . . . . . . . . 37 CleaningUp . . . . . . . . . . . . . . . . . . . . . 38 DrupalDirectlyinKubernetes-Let’sDoit[Mostly 38 DeployingtheDrupalKubernetesManifests . 39 Chapter5-ScalingDrupalink8s. . . . . . . . . . . . . 43 FixingthescalabilityissuewithDrupalPods . . . . 43 SharedStorageOptions . . . . . . . . . . . . . . 44 RookandCeph . . . . . . . . . . . . . . . . . . . 44 NFS . . . . . . . . . . . . . . . . . . . . . . . . . . 45 CONTENTS SetupanNFSserver . . . . . . . . . . . . . . . . . . . 46 Reconfigure the Drupal PersistentVolumeClaim forNFS . . . . . . . . . . . . . . . . . . . . . . 46 SetupNFSclientprovisionerinK8s . . . . . . 47 DeployDrupalandMySQL(MariaDB) . . . . . 48 SaveaFileandobserveit . . . . . . . . . . . . . 49 ScaleDrupalup…anddown! . . . . . . . . . . . . . . 49 UseHorizontalPodAutoscaling(HPA) . . . . . . . 51 Setupmetrics-server . . . . . . . . . . . . . . . 51 ConfiguringHPAforDrupal . . . . . . . . . . . 52 TestingHPAforDrupal . . . . . . . . . . . . . . 53 ScalingDatabases . . . . . . . . . . . . . . . . . . . . 54 Chapter6-DNS,TLS,Cron,Logging . . . . . . . . . . 56 SettingthingsupfromEpisode5 . . . . . . . . . . . 56 DNSandIngresssetupforDrupal . . . . . . . . . . . 57 SetupanNGINXIngressController . . . . . . 60 SetupIngressforDrupal . . . . . . . . . . . . . 61 ExternalDNSIntegration . . . . . . . . . . . . . 61 SetupTLSwithcert-managerandLet’sEncrypt. . 62 KeepingDrupalHappywithaCronJob . . . . . . . 65 MonitoringDrupal’sLogs. . . . . . . . . . . . . . . . 68 UsinganExternalSaaSLogAggregator . . . . 68 RunningyourownELKStack . . . . . . . . . . 69 RelyingonaServiceMesh . . . . . . . . . . . . 69 Usingyourcloudprovider’ssolution . . . . . . 70 Chapter7-Hello,Operator! . . . . . . . . . . . . . . . . 71 WhatareOperators? . . . . . . . . . . . . . . . . . . . 71 TheConcept . . . . . . . . . . . . . . . . . . . . . 72 TheExecution . . . . . . . . . . . . . . . . . . . . 73 WhynotuseanOperator? . . . . . . . . . . . . 75 PopularKubernetesOperators . . . . . . . . . . . . . 76 CONTENTS BuildyourownOperator . . . . . . . . . . . . . . . . 76 BuildinganOperatorwithOperatorSDK . . . 78 Anylanguage,includingPythonorRust! . . . 83 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 83 Chapter8-Kube,MeetPi . . . . . . . . . . . . . . . . . 84 HeavyMetalKubernetes . . . . . . . . . . . . . . . . 84 StartwithTrainingWheels . . . . . . . . . . . . . . . 85 TheRaspberryPimakesforCompactClusters 86 TheRaspberryPisipsenergy,andkeepsitscool 88 The Raspberry Pi teaches lessons about scala- bility . . . . . . . . . . . . . . . . . . . 89 ARMisnotallsunshineandroses . . . . . . . . 91 InstallingaKubernetesDistribution . . . . . . . . . 92 kubeadm . . . . . . . . . . . . . . . . . . . . . . . 93 SettinguptheRaspberryPiDramble . . . . . . . . . 94 GoingFurther . . . . . . . . . . . . . . . . . . . . . . . 95 OtherGuides . . . . . . . . . . . . . . . . . . . . 96 Chapter9-SecretsandConfiguration . . . . . . . . . 97 Chapter10-MonitoringKubernetes . . . . . . . . . . 98 TwoClusterstoMonitor. . . . . . . . . . . . . . 99 ClusterVisibilitywithLens. . . . . . . . . . . . . . . 99 InstallLens . . . . . . . . . . . . . . . . . . . . . . 100 InspectyourclusterswithLens . . . . . . . . . 100 ExplorePodLogs . . . . . . . . . . . . . . . . . . 101 LogintoNodesandPods . . . . . . . . . . . . . 101 Visitwebservicesinabrowser. . . . . . . . . . 103 Manageresources . . . . . . . . . . . . . . . . . . 103 PrometheusandGrafana . . . . . . . . . . . . . . . . 104 InstallPrometheusandGrafanausingHelm . 104 AccessGrafana . . . . . . . . . . . . . . . . . . . 105 GrafanaDashboards . . . . . . . . . . . . . . . . 108 CONTENTS MaintainingGrafana . . . . . . . . . . . . . . . . 108 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . 108 Afterword . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 Preface In 2020, the entire global community experienced a shock in theformoftheCOVID-19pandemic. Entire industries had to pivot overnight or risk ruin. Tech, fortunately for those of us in the industry, was suddenly in highdemand. Since I had a good deal of working knowledge about Ku- bernetes, and since I also finished a popular video series on Ansible earlier in the year, I decided to live-stream a series ‘Kubernetes 101’ to try to train people new to cloud-native infrastructureonthispopularclusteringsoftware. After many thousands of developers have viewed the video series, I decided to translate the content of the video series into this introductory-level book, so even more people could diveintoKubernetesandlearnanewskill. Whether you’re new to infrastructure, or you’re a veteran, Kubernetes can be complex and daunting. This book follows the progress of the video series, and starts with the basics, teaching each new concept with concrete, real-world exam- ples. IhopeyouenjoythebookasmuchasIenjoyedwritingit! —JeffGeerling,2021
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