Helm is a package manager for Kubernetes that simplifies the process of installing and managing applications on a cluster. Helm uses charts, which are a collection of files that describe a set of Kubernetes resources, to install applications.
During the process of installing an application, Helm first generates a set of Kubernetes YAML manifests based on the chart files. It then uses these manifests to create the actual resources on the cluster. However, sometimes the generated manifests may not work as expected, and it can be difficult to debug the issue. This is where Helm's dry run and template debug features come in handy.
In this article, we will explore how to use Helm's dry run and template debug features to troubleshoot issues during the installation of a chart.
Prerequisites
Before we begin, make sure that you have the following prerequisites:
- A Kubernetes cluster
- Helm installed on your machine
- A Helm chart to install
Helm Dry Run
The Helm dry run feature allows you to simulate the installation of a chart without actually creating any resources on the cluster. This is useful for verifying that the generated manifests are correct before actually installing the chart.
To perform a dry run, use the following command:
helm install <release-name> <chart-path> --dry-run
For example, if you have a chart named mychart in the current directory, you can perform a dry run with the following command:
helm install my-release ./mychart --dry-run
This command will output the generated manifests to the console without actually installing the chart. You can use this output to verify that the generated manifests are correct.
Helm Template Debug
Sometimes, even after performing a dry run, you may encounter issues when installing a chart. The Helm template debug feature allows you to debug the generated manifests by rendering them locally on your machine.
To use the template debug feature, use the following command:
helm install <release-name> <chart-path> --debug --dry-run
For example, to debug the manifests for the my-release release of the mychart chart, use the following command:
helm install my-release ./mychart --debug --dry-run
This command will output the rendered manifests to the console, along with the values of any variables used in the templates. You can use this output to debug any issues with the generated manifests.
Helm's dry run and template debug features are powerful tools that can help you troubleshoot issues when installing a chart on a Kubernetes cluster. By using these features, you can verify that the generated manifests are correct and debug any issues that you encounter.
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That's it for this post. Keep practicing and have fun. Leave your comments if any.