TL;DR

TIL helm template to expand templates locally for fun and testing.

When working with Helm charts it’s often useful to figure out what the expanded templates will look like, e.g. to spot errors in indentation or values that are fit inside.

Up to now, I was relying upon running helm install --dry-run --debug for this. This has the advantage of doing the most accurate simulation possible of the installation in a specific Kubernetes cluster, at the expense of… having a real Kubernetes cluster to play with.

This is not always the (well, my) case though, so I turned to the mighty internet and found out about the template sub-command, which is meant exactly for this:

Synopsis

Render chart templates locally and display the output.

Any values that would normally be looked up or retrieved in-cluster will be faked locally. Additionally, none of the server-side testing of chart validity (e.g. whether an API is supported) is done.

helm template [NAME] [CHART] [flags]

Thanks internet, and stay safe everyone!