2-crds.md

Creating an API

We will now create an API for our application. This consists of resources and controllers.

Steps

1. Create an API for the Toast:

operator-sdk create api --group breakfast --kind Toast --version v1 --resource --controller

2. Open api/v1/toast_types.go; notice the TODO comments.

Each API resource has a Spec, where you describe the parameters, and a Status.

3. Update the Toast API;

To the ToastSpec, add a Toastiness property:

// ToastSpec defines the desired state of Toast
type ToastSpec struct {
  // Toastiness is how long to cook the toast, from 0 (raw) to 10 (blackend)
  Toastiness int `json:"toastiness,omitempty"`
}

And to the ToastStatus add Toastiness and Ready properties:

// ToastStatus defines the observed state of Toast
type ToastStatus struct {
  // Toastiness is the current level of toastiness
  Toastiness int  `json:"toastiness,omitempty"`
  // Ready is whether the Toast has been fully cooked
  Ready bool `json:"ready,omitempty"`
  // LastUpdated is the last time the Toast was updated
  LastUpdated metav1.Time `json:"lastUpdated,omitempty"`
}

5. Update the API manifests

make manifests

Using the API

We can install the new Custom Resource Definition (CRD) for Toast into our cluster:

kubectl apply -f breakfast/config/crd/bases/breakfast.newredo.com_toasts.yaml

And we can create objects with kubectl. The operator SDK has created some sample YAML files for us; open the Toast sample in breakfast/config/samples/breakfast_v1_toast.yaml and add a toastiness property:

 spec:
-  # TODO(user): Add fields here
+  toastiness: 5

Let's create a Toast and view it with kubectl:

kubectl apply -f toast/config/samples/toast_v1_toast.yaml
kubectl get toast
kubectl describe toasts

Look at the 2-crds branch for the output from this step.

Next step

Creating a controller