Kubernetes Classroom Series – 03/Aug/2021

Helm Continued

• Lets try to understand Helm’s subcommands

• The abstracted complexity of k8s resources:
  • Let’s assume a developer has been given a task of deploying a Mysql database onto k8s.
  • Developer needs to create resources required to create containers, network and storage
  • With Helm, developer tasked with deploying a mysql database could simply search for MySQL Chart in chart repositories
• Automated Life cycle Hooks:
  • Helm provides the ability to define the life cylce hooks. Lifecycle hooks are actions that take place automatically at different stages of an application’s life cycle.
  • Examples:
    • Perform a data backup on an upgrade
    • Restore data on rollback
    • Validate k8s environment prior to installation

Installing Helm

Refer Here

Configuring Helm

• Helm is a tool with sensible default settings that allow users to be productive without needing to perform a large of post-installation tasks

• With that being said there are several options users can change or enable to modify the Helm’s behavior.

• Adding upstream repositories:

  • Helm provides the repo subcommand to allow users to manage configured chart repositories. This subcommand contains additional subcommands
    • add: To add a chart repository
    • list: To list chart repositories
    • remove: To remove the chart repository
    • update: To update information on available charts locally from chart repositories
    • index: To generate and index file given a directory containing packaged charts

• Example: Lets install mysql from bitnami repository Refer Here

  • Add bitnami repository as upstream
  • Install mysql
  • To uninstall mysql helm uninstall my-release

• Adding plugins:

  • Plugins are add-on capabilities that can be used to provide additional features to helm.
  • For managing plugins, helm has a subcommand plugin
  • Refer Here for some plugins

• ENVIRONMENT Variables: Helm relies on the existense of externalized environmental variables to configure low-level options

  • XDG_CACHE_HOME: Sets an alternative location for storing cached files
  • XDG_CONFIG_HOME: Sets an alternative location for storing helm configuration
  • XDG_DATA_HOME: Sets an alternative location for storing Helm Data
  • HELM_DRIVER: Sets the backend storage driver
  • HELM_NO_PLUGINS: Disables the plugins
  • KUBECONFIG: Sets an alternative Kubernetes configuration file

• Refer Here

• Helm has the following paths

  • Windows:
    • Cache Path: %TEMP%\helm
    • Configuration Path: %APPDATA%\helm
    • Data Path: %APPDATA%\helm
  • Linux:
    • Cache Path: $HOME/.cache/helm
    • Configuration Path: $HOME/.config/helm
    • Data Path: $HOME/.local/share/helm
  • Mac
    • Cache Path: $HOME/Libarary/Caches/helm
    • Configuration Path: $HOME/Library/Preferences/helm
    • Data Path: $HOME/Library/helm