book

Certified Kubernetes Administrator (CKA) Study Guide

by Benjamin Muschko

June 2022

Intermediate to advanced

201 pages

4h 42m

English

O'Reilly Media, Inc.

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Who This Book Is ForWhat You Will LearnConventions Used in This BookUsing Code ExamplesO’Reilly Interactive Katacoda LabsO’Reilly Online LearningHow to Contact UsAcknowledgments
Exam ObjectivesCurriculumCluster Architecture, Installation, and ConfigurationWorkloads and SchedulingServices and NetworkingStorageTroubleshootingInvolved Kubernetes PrimitivesExam Environment and TipsCandidate SkillsTime ManagementCommand-Line Tips and TricksSetting a Context and NamespaceUsing an Alias for kubectlUsing kubectl Command Auto-CompletionInternalize Resource Short NamesDeleting Kubernetes ObjectsFinding Object InformationDiscovering Command OptionsPracticing and Practice ExamsSummary
Role-Based Access ControlRBAC High-Level OverviewCreating a SubjectListing ServiceAccountsRendering ServiceAccount DetailsAssigning a ServiceAccount to a PodUnderstanding RBAC API PrimitivesDefault User-Facing RolesCreating RolesListing RolesRendering Role DetailsCreating RoleBindingsListing RoleBindingsRendering RoleBinding DetailsSeeing the RBAC Rules in EffectNamespace-wide and Cluster-wide RBACAggregating RBAC RulesCreating and Managing a Kubernetes ClusterInstalling a ClusterManaging a Highly Available ClusterUpgrading a Cluster VersionBacking Up and Restoring etcdBacking Up etcdRestoring etcdSummaryExam EssentialsSample Exercises
Managing Workloads with DeploymentsUnderstanding DeploymentsCreating DeploymentsListing Deployments and Their PodsRendering Deployment DetailsDeleting a DeploymentPerforming Rolling Updates and RollbacksRolling Out a New RevisionRolling Back to a Previous RevisionScaling WorkloadsManually Scaling a DeploymentManually Scaling a StatefulSetAutoscaling a DeploymentCreating Horizontal Pod AutoscalersListing Horizontal Pod AutoscalersRendering Horizontal Pod Autoscaler DetailsUsing the Beta API Version of an Horizontal Pod AutoscalerDefining and Consuming Configuration DataCreating a ConfigMapConsuming a ConfigMap as Environment VariablesMounting a ConfigMap as a VolumeCreating a SecretConsuming a Secret as Environment VariablesMounting a Secret as a VolumeSummaryExam EssentialsSample Exercises
Understanding How Resource Limits Affect Pod SchedulingDefining Container Resource RequestsDefining Container Resource LimitsDefining Container Resource Requests and LimitsManaging ObjectsDeclarative Object Management Using Configuration FilesDeclarative Object Management Using KustomizeCommon Templating ToolsUsing the YAML Processor yqUsing HelmSummaryExam EssentialsSample Exercises
Kubernetes Networking BasicsConnectivity Between ContainersConnectivity Between PodsUnderstanding ServicesService TypesCreating ServicesListing ServicesRendering Service DetailsPort MappingAccessing a Service with Type ClusterIPAccessing a Service with Type NodePortAccessing a Service with Type LoadBalancerUnderstanding IngressIngress RulesCreating IngressesDefining Path TypesListing IngressesRendering Ingress DetailsAccessing an IngressUsing and Configuring CoreDNSInspecting the CoreDNS PodInspecting the CoreDNS ConfigurationCustomizing the CoreDNS ConfigurationDNS for ServicesResolving a Service by Hostname from the Same NamespaceResolving a Service by Hostname from a Different NamespaceDNS for PodsResolving a Pod by HostnameChoosing an Appropriate Container Network Interface PluginSummaryExam EssentialsSample Exercises
Understanding VolumesVolume TypesCreating and Accessing VolumesUnderstanding Persistent VolumesStatic vs. Dynamic ProvisioningCreating PersistentVolumesConfiguration Options for a PersistentVolumeVolume ModeAccess ModeReclaim PolicyCreating PersistentVolumeClaimsMounting PersistentVolumeClaims in a PodUnderstanding Storage ClassesCreating Storage ClassesUsing Storage ClassesSummaryExam EssentialsSample Exercises
Evaluating Cluster and Node LoggingCluster LoggingNode LoggingMonitoring Cluster Components and ApplicationsTroubleshooting Application FailuresTroubleshooting PodsOpening an Interactive ShellTroubleshooting ServicesTroubleshooting Cluster FailuresTroubleshooting Control Plane NodesTroubleshooting Worker NodesSummaryExam EssentialsSample Exercises
Chapter 2, “Cluster Architecture, Installation, and Configuration”Chapter 3, “Workloads”Chapter 4, “Scheduling and Tooling”Chapter 5, “Services and Networking”Chapter 6, “Storage”Chapter 7, “Troubleshooting”

Content preview from Certified Kubernetes Administrator (CKA) Study Guide

Chapter 6. Storage

When container images are instantiated as containers, the container needs context—context to CPU, memory, and I/O resources. Pods provide the network and the filesystem context for the containers within. The network is provided as the Pod’s virtual IP address, and the filesystem is mounted to the hosting node’s filesystem. Applications running in the container can interact with the filesystem as part of the Pod context. A container’s temporary filesystem is isolated from any other container or Pod and is not persisted beyond a Pod restart. The “Storage” section of the CKA curriculum addresses the technical abstraction in Kubernetes responsible for persisting data beyond a container or Pod restart.

A volume is a Kubernetes capability that persists data beyond a Pod restart. Essentially, a volume is a directory that’s shareable between multiple containers of a Pod. You will learn about the different volume types and the process for defining and mounting a volume in a container.

Persistent volumes are a specific category of the wider concept of volumes. The mechanics for persistent volumes are slightly more complex. The persistent volume is the resource that actually persists the data to an underlying physical storage. The persistent volume claim represents the connecting resource between a Pod and a persistent volume responsible for requesting the storage. Finally, the Pod needs to claim the persistent volume and mount it to a directory path available to the containers ...