How can you use Helm charts to simplify Kubernetes deployment?

1 What are the benefits of Helm charts?

Helm charts offer several benefits for data engineering projects that use Kubernetes as their platform. First, Helm charts enable you to define and reuse templates for common components, such as databases, message queues, or web servers, that can be customized with variables and functions. This reduces duplication and errors, and makes your charts more maintainable and portable. Second, Helm charts allow you to manage the lifecycle of your applications, such as installing, upgrading, rolling back, or uninstalling them, using simple commands and flags. This makes your deployment process more consistent and reliable, and saves you time and resources. Third, Helm charts support dependencies and subcharts, which enable you to modularize and organize your applications into logical units, and to leverage existing charts from the official or community repositories. This enhances the scalability and reusability of your applications, and simplifies the integration of different services and components.

2 How do you create a Helm chart?

To create a Helm chart, you need to have Helm installed on your machine and a Kubernetes cluster running. You can use the helm create command to generate a basic chart structure with some default files and folders. The main files you need to edit are:

- Chart.yaml : This file contains the metadata of your chart, such as the name, version, description, and dependencies of your chart.

- values.yaml : This file contains the default values for the variables and parameters that are used in your templates. You can override these values with custom values files or command-line arguments when installing or upgrading your chart.

- templates/ : This folder contains the YAML files that define the Kubernetes resources that your chart creates, such as pods, services, deployments, or configmaps. You can use the {{ .Values }} syntax to reference the values from the values.yaml file, and the {{ .Release }} or {{ .Chart }} syntax to access the information about the release or the chart. You can also use Helm template functions and control structures to add logic and customization to your templates.

3 How do you install a Helm chart?

To install a Helm chart, you need to have a Kubernetes cluster running and access to the chart source code or the packaged chart file. You can use the helm install command to deploy your chart to the cluster, specifying a name for the release and the location of the chart. For example, helm install my-app ./my-chart will install the chart from the my-chart folder with the release name my-app . You can also use the --values flag to provide a custom values file, or the --set flag to override individual values. For example, helm install my-app ./my-chart --values my-values.yaml --set image.tag=v1.0 will install the chart with the values from the my-values.yaml file and the image tag set to v1.0 .

4 How do you upgrade a Helm chart?

To upgrade a Helm chart, you need to have a Kubernetes cluster running and access to the updated chart source code or the packaged chart file. You can use the helm upgrade command to update your release with the new version of the chart, specifying the name of the release and the location of the chart. For example, helm upgrade my-app ./my-chart will upgrade the release my-app with the chart from the my-chart folder. You can also use the same flags as the helm install command to provide custom values or override individual values. For example, helm upgrade my-app ./my-chart --values my-values.yaml --set image.tag=v2.0 will upgrade the release with the values from the my-values.yaml file and the image tag set to v2.0 . Additionally, you can use the --history-max flag to limit the number of revisions that are stored for your release, or the --atomic flag to roll back the release if the upgrade fails.

5 How do you uninstall a Helm chart?

To uninstall a Helm chart, you need to have a Kubernetes cluster running and access to the release name of the chart. You can use the helm uninstall command to remove your release from the cluster, specifying the name of the release. For example, helm uninstall my-app will delete the release my-app and all the associated resources from the cluster. You can also use the --keep-history flag to preserve the release history, or the --dry-run flag to simulate the uninstallation without actually deleting anything.

6 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?