helm/docs/chart_best_practices/third_party_resources.md

Third Party Resources

This section of the Best Practices Guide deals with creating and using Third Party Resource objects.

When working with Third Party Resources (TPRs), it is important to distinguish two different pieces:

• There is a declaration of a TPR. This is the YAML file that has the kind ThirdPartyResource
• Then there are resources that use the TPR. Say a TPR defines foo.example.com/v1. Any resource that has apiVersion: example.com/v1 and kind Foo is a resource that uses the TPR.

Install a TPR Declaration Before Using the Resource

Helm is optimized to load as many resources into Kubernetes as fast as possible. By design, Kubernetes can take an entire set of manifests and bring them all online (this is called the reconciliation loop).

But there's a difference with TPRs.

For a TPR, the declaration must be registered before any resources of that TPRs kind(s) can be used. And the registration process sometimes takes a few seconds.

Method 1: Separate Charts

One way to do this is to put the TPR definition in one chart, and then put any resources that use that TPR in another chart.

In this method, each chart must be installed separately.

Method 2: Pre-install Hooks

To package the two together, add a pre-install hook to the TPR definition so that it is fully installed before the rest of the chart is executed.

Note that if you create the TPR with a pre-install hook, that TPR definition will not be deleted when helm delete is run.