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Exercise 1

In this exercise you will complete the following:

  • Create Operator scaffolding in Ansible
  • Add a simple debug print statement to the operator Ansible role
  • Update the operator Custom Resource (CR) and add a parameter to toggle the print statement
  • Test the operator using the ansible-runner

Step 1: Open your OpenShift web console and copy the login command

  • Select Copy Login Command

  • Press Display Token

  • Copy Log in with this token

  • Insert in your terminal session
oc login --token=7DMj4CRxuUCzXXXXXXXXXX --server=https://XXXXX.com:30596
  • Verify your login

Example output:

Step 2: Create a new OpenShift project

oc new-project operator-helloworld

Example output:

Step 3: Create Operator Scaffolding

Using the operator-sdk, create the scaffolding for your new operator.

The operator-sdk will generate an Ansible role, create a new custom resource definition (CRD) and all the necessary k8s objects to install the operator. This is a two step process. First initialize and then create API.

mkdir operator-helloworld

cd operator-helloworld

operator-sdk init --plugins=ansible --domain=hello.example.com

The image below show the created folders and files.

operator-sdk create api --group cache --version v1 --kind Hello --generate-role

Step 4: Create Custom Resource Definition (CRD)

The operator-sdk will generate a Custom Resource Definition (CRD).

The Custom Resource Definition (CRD) will extend the k8s API and allow users to interact with the Operator through the API.

Here we will install Custom Resource Definition (CRD) in the current project operator-helloworld.

make install

Example output:

Note: To inspect what happens during the install, just open the Makefile.

nano Makefile
Example output:

Optional Step 4.1: Inspect the created Custom Resource Definition (CRD) in your cluster

  • Open OpenShift web console and select Administration -> Custom Resource Definitions and insert hello into the search field.

  • Press Hello and you see the details of the Custom Resource Definitions.

Step 5: Add Print Task to Operator Role

The operator framework implements Ansible roles. 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. In this case we will be adding a print statement that will print some debug when a parameter toggle_message is set to true to the role.

  • Open the ./watches.yaml file and inspect the content.
nano watches.yaml

# Use the 'create api' subcommand to add watches to this file.
- version: v1
  group: cache.hello.example.com
  kind: Hello
  role: hello
# +kubebuilder:scaffold:watch
  • Open the ./roles/hello/tasks/main.yml file and insert the print statement.
nano roles/hello/tasks/main.yml

The content to add to the main.yml

---
# tasks file for hello
- name: Hello World Task
  debug:
    msg: "Hello World! I live in a namespace called {{ ansible_operator_meta.namespace }}"
  when: toggle_message

Step 6: Add parameter to the Operator Custom Resource

Here we will add the toggle_message parameter to the CR. Any parameters under the CR spec are automatically visible in Ansible.

This is how you get input from your users. In addition as you may have noticed you can access CR metadata using the ansible_operator_meta parameter in ansible. In the above example that is the name os the namespace.

nano config/samples/cache_v1_hello.yaml

Content to add to cache_v1_hello.yaml file. foo: bar will be replaced with toggle_message: true.

apiVersion: cache.hello.example.com/v1
kind: Hello
metadata:
  name: hello-sample
spec:
  toggle_message: true

Step 7: Run Operator using ansible-runner

Now that we have implemented some tasks and our parameter we can run ther Operator locally using the ansible-runner to test it. 

ansible-operator run local

Example output:

Step 8: Create a hello custom resource

Open another terminal and create the CR in your OpenShift cluster. Once the CR is created, the Operator will execute the Ansible role tasks and print our debug message.

oc create -f config/samples/cache_v1_hello.yaml
Example output second terminal:

Example output first terminal: 

TASK [Hello World Task] ********************************
ok: [localhost] => {
    "msg": "Hello World! I live in a namespace called operator-helloworld"
}