mirror of https://github.com/helm/helm
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
38 lines
1.5 KiB
38 lines
1.5 KiB
# Custom Resource Definitions
|
|
|
|
This section of the Best Practices Guide deals with creating and using Custom Resource Definition
|
|
objects.
|
|
|
|
When working with Custom Resource Definitions (CRDs), it is important to distinguish
|
|
two different pieces:
|
|
|
|
- There is a declaration of a CRD. This is the YAML file that has the kind `CustomResourceDefinition`
|
|
- Then there are resources that _use_ the CRD. Say a CRD defines `foo.example.com/v1`. Any resource
|
|
that has `apiVersion: example.com/v1` and kind `Foo` is a resource that uses the CRD.
|
|
|
|
## Install a CRD 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 CRDs.
|
|
|
|
For a CRD, the declaration must be registered before any resources of that CRDs
|
|
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 CRD definition in one chart, and then put any
|
|
resources that use that CRD 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 CRD definition so
|
|
that it is fully installed before the rest of the chart is executed.
|
|
|
|
Note that if you create the CRD with a `pre-install` hook, that CRD definition
|
|
will not be uninstalled when `helm uninstall` is run.
|