Helm Fundamentals

Helm Fundamentals: Managing Kubernetes Deployments with Helm

Helm is the de facto package manager for Kubernetes, simplifying application deployment and management.

Exploring ArtifactHub and Helm Repositories

• ArtifactHub is a central repository where users can discover and share Helm charts, operators, and other Kubernetes resources.
• It allows users to browse and search for Helm charts maintained by the community and official providers.
• Visit ArtifactHub to explore available charts and their documentation.

Managing Helm Repositories with the Helm CLI ⚙️

• Helm repositories store and distribute Helm charts.

• The default Helm repository is Helm’s official stable repository, but users can add custom repositories.

• Adding a Helm Repository

  helm repo add bitnami https://charts.bitnami.com/bitnami
  

• Listing Available Repositories

  helm repo list
  

• Updating the Helm Repository

  helm repo update
  

Installing Charts ⚡

• Installing the WordPress Helm Chart

  • Let’s install the WordPress Helm chart from the Bitnami repository:

    helm install my-wordpress bitnami/wordpress
    

  • This deploys WordPress in a Kubernetes cluster with default configurations.

• Exploring the Default WordPress Chart Configuration

  • After installation, you can check the installed resources:

    kubectl get all
    

  • To inspect the default configuration:

    helm show values bitnami/wordpress
    

Uninstalling Helm Charts and Cleaning Up Resources

• To uninstall the WordPress deployment:

  helm uninstall my-wordpress
  

• This removes the release but not persistent volumes. To delete all associated resources, manually remove PVCs:

  kubectl delete pvc --all
  

Managing Chart Dependencies ⚙️

• Helm charts can have dependencies on other charts, defined in the Chart.yaml file.

• To manage dependencies:

• Adding Dependencies to Chart.yaml

  dependencies:
    - name: mysql
      version: "8.0.0"
      repository: "https://charts.bitnami.com/bitnami"
  

• Updating Dependencies⚡

• Run the following command to fetch and update dependencies:

  helm dependency update
  

Setting Values

• Setting Custom Values via the Helm CLI

  • You can override default values while installing a chart: ⚙️️

    helm install my-wordpress bitnami/wordpress --set wordpressUsername=admin,wordpressPassword=secret
    

• Setting Custom Values via Files ✍️

  • Instead of passing values in CLI, store them in a file:

    wordpressUsername: admin
    wordpressPassword: secret
    

  • Install the chart with:

    helm install my-wordpress bitnami/wordpress -f custom-values.yaml
    

Release Upgrades and Rollbacks ⏳

• Upgrading Helm Releases: Setting New Values ⚙️

  • Modify values and upgrade the release:

    helm upgrade my-wordpress bitnami/wordpress --set wordpressEmail=admin@example.com
    

• Upgrading Helm Releases: Setting New Chart Versions 

  • To upgrade to a specific version:

    helm upgrade my-wordpress bitnami/wordpress --version 10.1.0
    

• Rollbacks in Helm ⏪

  • If an upgrade fails, roll back to a previous version:

    helm rollback my-wordpress 1
    

  • Check revision history with:

    helm history my-wordpress
    

• Upgrading Helm Releases: Useful CLI Flags⚡

  • --atomic: Rollback automatically if the upgrade fails.
  • --dry-run: Preview changes before applying.

  • --debug: Get detailed error logs.

  • Example:

    helm upgrade my-wordpress bitnami/wordpress --set wordpressTitle="My Blog" --atomic --debug
    

Conclusion

Helm simplifies Kubernetes deployments, allowing users to manage applications efficiently. From discovering charts on ArtifactHub to managing values, dependencies, and rollbacks, Helm provides powerful tools to streamline Kubernetes operations. ⚡

Try out Helm in your cluster and explore its potential!