dummy-controller

A small Kubernetes Custom Controller in Go.

Define a Custom Resource and a Controller that Logs the Spec of the Custom Resource

Initializing the Operator

using operator-sdk, execute the below command to init the custom controller

operator-sdk init --domain interview.com --repo gitlab.com/rfashwal/dummy-controller

Create Dummy API

• execute the below command for api creation

operator-sdk create api --group=interview --version=v1alpha1 --kind=Dummy

• create the resource and the controller

Create Resource [y/n]
y
Create Controller [y/n]
y

Generate controller and manifests

make manifests
make generate

Customising Dummy Spec and update controller

Open the generated file api/v1alpha1/dummy_types.go and modify it to define the structure of the Dummy custom resource spec, update the controller logic accordingly.

Deploying

A CI process will build the image and push it to the registry where it can be used to deploy the controller Deploy the controller after the image is pushed:

 make deploy IMG=rfashwal/dummy-controller:1-init-dummy-operator

Give Dummies a Status and Make the Custom Controller Write to it

Update the status of Dummy crd to include SpecEcho and follow the above steps to build and deploy

Associate a Pod to each Dummy API object

• Update Dummy status to include podStatus
• Update controller to check for pod if not found, create the pod
• Update the dummy staus to include podStatus

Testing

Prerequisites

• initiate a Kubernetes cluster using kind or minikube
• kubectl command-line tool
• Docker
• Operator SDK

Image registry

• The release images are found under: https://hub.docker.com/repository/docker/rfashwal/dummy-controller/tags?page=1&ordering=last_updated For each step, a branch is created and image is released, so you can test any step independently. latest tag is the final working controller as specified.

Local testing

• clone the repo: git clone [email protected]:rfashwal/dummy-controller.git
• deploy with target image tag: make deploy IMG=rfashwal/dummy-controller:{tag}