deploymentgroup

This repository implements a simple controller for watching Foo resources as defined with a CustomResourceDefinition (CRD).

This particular example demonstrates how to perform basic operations such as:

• How to register a new custom resource (custom resource type) of type Foo using a CustomResourceDefinition.
• How to create/get/list instances of your new resource type Foo.
• How to setup a controller on resource handling create/update/delete events.

It makes use of the generators in k8s.io/code-generator to generate a typed client, informers, listers and deep-copy functions. You can do this yourself using the ./hack/update-codegen.sh script.

The update-codegen script will automatically generate the following files & directories:

• pkg/apis/deploymentgroup/v1alpha1/zz_generated.deepcopy.go
• pkg/generated/

Changes should not be made to these files manually, and when creating your own controller based off of this implementation you should not copy these files and instead run the update-codegen script to generate your own.

Details

The sample controller uses client-go library extensively.

Note that if you intend to generate code then you will also need the code-generator repo to exist in an old-style location. One easy way to do this is to use the command go mod vendor to create and populate the vendor directory.

A Note on kubernetes/kubernetes

Running

Prerequisite: Since the sample-controller uses apps/v1 deployments, the Kubernetes cluster version should be greater than 1.9.

Subresources

Custom Resources support /status and /scale subresources. The CustomResourceSubresources feature is in GA from v1.16.

A Note on the API version

The group version of the custom resource in crd.yaml is v1alpha, this can be evolved to a stable API version, v1, using CRD Versioning.

Compatibility

HEAD of this repository will match HEAD of k8s.io/apimachinery and k8s.io/client-go.