Getting Started

This section will guide you through the steps to get started with Cuestomize.

01. The CUE Model

To get started with Cuestomize, you need to create a CUE module that defines your manifest generation logic.

You can either create your own CUE model from scratch, or use an existing one.

How to create CUE models that are compatible with Cuestomize is explained in different sections of this book, so we will use one of the existing models for this example.

You need to have a Kustomization directory that you can use to run Kustomize. In this directory, you need to create a kustomization.yaml file that defines the resources you want to manage with Kustomize.

How to create a Kustomization project is out of the scope of this book, so we will assume you already have one, and the next steps will assume you are using the one under examples/simple/kustomize.

In your kustomization directory, you need to add a file that holds the configuration of the KRM function that will run Cuestomize. The name you give to this file is not important, as long as you reference it in the transformers section of your kustomization.yaml file.

Create the KRM Function Configuration File

Change directory, and create a file named krm-func.yaml in the kustomization directory:

# We assume you have git cloned the repo locally and are in the root directory of the repo
cd examples/simple/kustomize

touch krm-func.yaml

Note: the name you give to this file is not important, as long as you reference it in the transformers section of your kustomization.yaml file.

Update the Kustomization File

Edit the kustomization.yaml file to add the krm-func.yaml file to the transformers section:

kind: Kustomization

# ... other sections ...

transformers:
- krm-func.yaml

03. Configuring the KRM Function

Edit the krm-func.yaml file to configure the KRM function that will run Cuestomize.

Here is an example configuration:

apiVersion: cuestomize.dev/v1alpha1
kind: Cuestomization
metadata:
  name: example
  annotations:
    config.kubernetes.io/local-config: "true"
    config.kubernetes.io/function: |
      container:
        image: ghcr.io/workday/cuestomize:latest
        network: true
input:
  configMapName: example-configmap
includes:
- group: apps
  version: v1
  kind: Deployment
  name: example-deployment
  namespace: example-namespace
- version: v1
  kind: Service
  name: example-service
  namespace: example-namespace
remoteModule:
  registry: ghcr.io
  repo: workday/cuestomize/cuemodules/cuestomize-examples-simple
  tag: latest

Note: Cuestomize does not constrain the apiVersion and kind fields of the KRM function configuration, so you can use whatever values you want, as long as they are valid Kubernetes resource names. In your CUE model, on the other hand, you can constrain these to specific values in order to ensure compatibility between the model and the function's configuration.

04. Running Kustomize to Generate the Manifests

Now that you have everything set up, you can run Kustomize to generate the manifests.

Since Cuestomize is a KRM function, you'll need a few extra flags in order for kustomize build to work properly:

--enable-alpha-plugins to enable the KRM function
--network if your CUE model is pulled from a registry (can be omitted if the model is local to the function's image).

Build the Manifests

kustomize build . --enable-alpha-plugins --network

You should see the build to be successful, and the CUE-generated manifests within the printed manifests.

The Cuestomize Book