Kustomize Transformer Configurations for Cluster API v1alpha3

A few days ago I wrote an article on configuring kustomize transformers for use with Cluster API (CAPI), in which I explored how users could configure the kustomize transformers—the parts of kustomize that actually modify objects—to be a bit more CAPI-aware. By doing so, using kustomize with CAPI manifests becomes much easier. Since that post, the CAPI team released v1alpha3. In working with v1alpha3, I realized my kustomize transformer configurations were incorrect. In this post, I will share CAPI v1alpha3 configurations for kustomize transformers.

In the previous post, I referenced changes to both namereference.yaml (to configure the nameReference transformer) and commonlabels.yaml (to configure the commonLabels transformer). CAPI v1alpha3 has changed the default way labels are used with MachineDeployments, so for v1alpha3 you may be able to get away with only changes to namereference.yaml. (If you know you are going to want/need additional labels on your MachineDeployment, then plan on changes to commonlabels.yaml as well.)

Here are the CAPI v1alpha3 changes needed to namereference.yaml:

- kind: Cluster
  group: cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/clusterName
    kind: MachineDeployment
  - path: spec/template/spec/clusterName
    kind: MachineDeployment

- kind: AWSCluster
  group: infrastructure.cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/infrastructureRef/name
    kind: Cluster

- kind: KubeadmControlPlane
  group: controlplane.cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/controlPlaneRef/name
    kind: Cluster

- kind: AWSMachine
  group: infrastructure.cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/infrastructureRef/name
    kind: Machine

- kind: KubeadmConfig
  group: bootstrap.cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/bootstrap/configRef/name
    kind: Machine

- kind: AWSMachineTemplate
  group: infrastructure.cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/template/spec/infrastructureRef/name
    kind: MachineDeployment
  - path: spec/infrastructureTemplate/name
    kind: KubeadmControlPlane

- kind: KubeadmConfigTemplate
  group: bootstrap.cluster.x-k8s.io
  version: v1alpha3
  fieldSpecs:
  - path: spec/template/spec/bootstrap/configRef/name
    kind: MachineDeployment

You also need to include this line in your kustomization.yaml (to bring in the transformer configuration):

configurations:
- /path/to/customized/namereference.yaml

If you do need to edit commonlabels.yaml, the changes for CAPI v1alpha3 are the same as described in the previous article. You’ll then need to add an entry to your configurations: line, as noted above.

For information on configuring kustomize transformers to support the v1beta1 version of Cluster API, please see this follow-up post.

I hope this helps! Find me on Twitter or on the Kubernetes Slack instance if you have any questions, comments, or corrections.

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