If you want to perform dry run on helm without installing an application on kubernetes, helm will help us to first create kubernetes yaml manifest ffiles based on the helm chart files. Later this manifests file can be used to create the resources on kubernetes cluster.
This post will show you how to use helm dry run and how to debug template to troubleshoot the issues during the helm chart installlation.
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Prerequisites
Here is the prerequisites, make sure you have the following prerequisites are met:
- 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.
Helm dry run command helps us to create the manifests file without creating the actual resources on kubernetes cluster, This will be useful if you want to change anything or debug any issues. Use the below helm install command to perform dry run.
helm install <release-name> <chart-path> --dry-run
Let's sat, you have helm chart called mychart in current directory, then you can perform the dry run with the following helm install command:
helm install my-release ./mychart --dry-run
Above helm install command will show your the generated manifests in the console itself without actually installing helm chart. You can see the output to verify that the generated manifests are correct or not.
Helm Template Debug
On some cases, we have to perform dry run even after installing helm charts. Because, we may be encountering issues when installing helm charts. Helm template has the feature for debuging that allows you us to debug the generated manifests by rendering them locally.
use the below helm install command to use template debug feature.
helm install <release-name> <chart-path> --debug --dry-run
Here is the helm install command example. Let's say, If you want to debug the manifests for my-release release of mychart helm chart, use the below helm install command:
helm install my-release ./mychart --debug --dry-run
Above helm install command will show you the output of rendered manifests in the screen along with the values of any variables used in the templates. You can use this output to debug any issues with the generated manifests.
That's it for this post. Keep practicing and have fun. Leave your comments if any.
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