Additional information¶

Relevant files in the `Asible Operator SDK`¶

[PROJECT_ROOT]/watches.yaml

By default it will create a single role, but you can certainly have many roles. Roles are mapped to the API endpoint of the CRD in the watches.yaml file.

[PROJECT_ROOT]/roles/hello/tasks/main.yml

Defining the task for the role hello.

[PROJECT_ROOT]/config/samples/cache_v1_hello.yaml

With this YAML file you create a custom resource in RedHat OpenShift.

[PROJECT_ROOT]/config/rbac/role.yaml

This role YAML file containes the permissions we need to create and modify resources in RedHat OpenShift.

[PROJECT_ROOT]/config/default/kustomization.yaml

This kustomization `YAML file contains the information for the container image we will create as our operator.

Using `Podman` in the `Makefile`¶

If you use Podman you need to edit the Makefile replace docker with podman.

...
# Build the docker image
docker-build:
    podman build . -t ${IMG}

# Push the docker image
docker-push:
    podman push ${IMG}
...
bundle-build:
    podman build -f bundle.Dockerfile -t $(BUNDLE_IMG) .
...

Building a Ubuntu VirtualBox image¶

Maybe this is useful when you build your own Ubunto VirtualBox image and with Podman.

Understand Custom Resource definition¶

For more details visit Kubernetes Documentation for Custom Resource Definitions

Step 1: Set project context¶

oc project default

Step 2: Get pod for this project¶

oc get pods

Step 3: Get pod custom resource¶

oc get awesome

Example output:

error: the server doesn't have a resource type "awesome"

Step 4: Define custom resource¶

Create a file called awesome-crd.yamland past in following content.

apiVersion: apiextensions.k8s.io/v1
kind: CustomResourceDefinition
metadata:
  # name must match the spec fields below, and be in the form: <plural>.<group>
  name: awesomes.my.example.com
spec:
  # group name to use for REST API: /apis/<group>/<version>
  group: my.example.com
  # list of versions supported by this CustomResourceDefinition
  versions:
    - name: v1
      served: true
      storage: true
      schema:
        openAPIV3Schema:
          type: object
          properties:
            host:
              type: string
            port:
              type: string
  # either Namespaced or Cluster
  scope: Namespaced
  names:
    # plural name to be used in the URL: /apis/<group>/<version>/<plural>
    plural: awesomes
    # singular name to be used as an alias on the CLI and for display
    singular: awesome
    # kind is normally the CamelCased singular type. Your resource manifests use this.
    kind: Awesome
    # shortNames allow shorter string to match your resource on the CLI
    shortNames:
    - as

oc create -f awesome-crd.yaml

Example output:

customresourcedefinition.apiextensions.k8s.io/awesomes.my.example.com created

Step 5: Get existing resources¶

oc get awesomes

Example output:

No resources found in default namespace.

Step 6: Create a resource instance¶

Now we use our defined custom resource. Create a file called awesome-crd-create.yamland past in following content.

apiVersion: my.example.com/v1
kind: Awesome
metadata:
  name: my-awesome-instance
spec:
  user: my-awesome-user

oc create -f awesome-crd-create.yaml

Example output:

awesome.my.example.com/my-awesome-instance created

Step 7: Get instance¶

oc get awesomes

Example output:

NAME                  AGE
my-awesome-instance   38s