book

Learning Helm

by Matt Butcher, Matt Farina, Josh Dolitsky

January 2021

Beginner to intermediate

212 pages

5h 38m

English

O'Reilly Media, Inc.

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Who Should Read This BookWhy We Wrote This BookNavigating This BookConventions Used in This BookUsing Code ExamplesO’Reilly Online LearningHow to Contact UsAcknowledgments
The Cloud Native EcosystemContainers and MicroservicesSchedules and KubernetesHelm’s GoalsFrom Zero to KubernetesPackage ManagementSecurity, Reusability, and ConfigurabilityHelm’s ArchitectureKubernetes ResourcesChartsResources, Installations, and ReleasesA Brief Note About Helm 2Conclusion
Installing and Configuring the Helm ClientInstalling a Prebuilt BinaryGuidance on Building from SourceWorking with Kubernetes ClustersGetting Started with HelmAdding a Chart RepositorySearching a Chart RepositoryInstalling a PackageConfiguration at Installation TimeListing Your InstallationsUpgrading an InstallationConfiguration Values and UpgradesUninstalling an InstallationHow Helm Stores Release InformationConclusion
Templating and Dry RunsThe --dry-run FlagThe helm template CommandLearning About a ReleaseRelease RecordsListing ReleasesFind Details of a Release with helm getHistory and RollbacksKeeping History and Rolling BackA Deep Dive into Installs and UpgradesThe --generate-name and --name-template FlagsThe --create-namespace FlagUsing helm upgrade --installThe --wait and --atomic FlagsUpgrading with --force and --cleanup-on-failConclusion
The Chart Creation CommandThe Chart.yaml FileModifying TemplatesThe DeploymentUsing the Values FileContainer ImagesExposing ServicesResource LimitsPackaging the ChartLinting ChartsConclusion
The Template SyntaxActionsInformation Helm Passes to TemplatesPipelinesTemplate FunctionsMethodsQuerying Kubernetes Resources In Chartsif/else/withVariablesLoopsNamed TemplatesStructuring Your Templates for MaintainabilityDebugging TemplatesDry RunGetting Installed ManifestsLinting ChartsConclusion
Chart DependenciesConditional Flags for Enabling DependenciesImporting Values from Child to Parent ChartsLibrary ChartsSchematizing Values FilesHooksAdding Tests to ChartsHelm TestChart Testing ToolSecurity ConsiderationsCustom Resource DefinitionsConclusion
The Repository IndexAn Example of a Chart Repository IndexGenerating an IndexAdding to an Existing IndexSetting Up a Chart RepositoryA Simple Chart Repository with PythonSecuring a Chart RepositoryReal-World Example: Using GitHub PagesUsing Chart RepositoriesAdding a RepositoryDownloading ChartsListing RepositoriesUpdating RepositoriesRemoving a RepositoryExperimental OCI SupportEnabling OCI SupportRunning a Local RegistryLogging In to a RegistryLogging Out of a RegistryStoring a Chart in the CacheListing Charts in the CacheExporting a Chart from the CachePushing a Chart to the RegistryPulling a Chart from the RegistryRemoving a Chart from the CacheRelated ProjectsChartMuseumHarborChart ReleaserS3 PluginGCS PluginGit Plugin
PluginsInstalling Third-Party PluginsCustom SubcommandsBuilding a Pluginplugin.yamlHooksDownloader PluginsExecution EnvironmentShell CompletionStartersConverting a Chart to a StarterMaking Starters Available to HelmUsing StartersExtending Helm Further
API Version 2The Chart.yaml FileThe Chart.lock FileAPI Version 1 (legacy)The Chart.yaml FileThe requirements.yaml File (Legacy)The requirements.lock File (Legacy)

index.yamlThe index.yaml FormatWhen Is index.yaml Downloaded?When Is the Cached Version of index.yaml Used?.tgz FilesWhen Are .tgz Files Downloaded?.prov FilesWhen Are .prov Files Downloaded?

Content preview from Learning Helm

Preface

Helm is the package manager for Kubernetes, the popular open source container management platform.

Package managers make platforms more accessible to those who use them. In order to use a platform like Kubernetes, you need to run software on it, and much of that software will be off-the-shelf or shared. Package managers like Helm enable you to install and start using the software quickly without needing to figure out how to make it run or run well on the platform, because it has already been packaged up in an easy-to-use manner.

If you have software you want to share with others, package managers make it easy to do. Platforms are more useful when there is a wide variety of software to run on them; open source projects and companies both like to make their software easy to install on the platforms it runs on, and Helm makes this possible for Kubernetes.

Package managers aren’t just for sharing and consuming others’ software, however. They are often an integral part of other systems, such as DevOps tooling, and they are used as a building block.

Virtually every modern platform has a package manager. Operating systems, programming languages, and cloud platforms all have package managers of some form.

In this book you will learn about Helm, which provides modern package management for Kubernetes, and the packages, called charts, that you can use with it. You will learn how to use Helm, how to create packages, and how to share those packages with other platforms.