Introduction to the Kubernetes Operator Resource

The CTE for Kubernetes Operator is an OpenShift operator that Thales created for CTE for Kubernetes. The Kubernetes Operator can deploy, monitor, upgrade and delete CTE for Kubernetes. When the Operator is deployed, its controller deploys the CTE for Kubernetes driver in the OpenShift cluster. The manifests required to deploy the CTE-K8s driver are bundled with the operator.

Kubernetes has various default resources like Pod, Deployment, DaemonSet, etc. When you define a manifest for instantiating one of those resources, you must specify the Kind as Pod/Deployment/DaemonSet etc. Kubernetes provides a default set of controllers that understand the resource definitions and know how to manage their life cycle. For instance, the Deployment Controller manages the Create/Update/Delete of the Deployment resource.

Kubernetes architecture allows users to extend the API server in a way that users can create their own custom resource (CR) and write their own controller to manage the custom resource. An operator bundles a CR and the Controller that manages the CR. An operator can watch resources across the cluster and take actions when required. The operator contains a CR, an API for managing a CR, and a custom controller that manages this resource. When you install the CTE for Kubernetes Operator on an OpenShift cluster, the operator registers the new CR and the controller with the Kubernetes API server. Whenever the API server receives a request to create a resource, where Kind=CTEK8sOperator, it passes on the request to CTE for Kubernetes Operator’s Custom Controller. The controller contains all of the logic needed to complete tasks before, during or after the deployment of the driver.

For more information on how to use operators to manage other applications, refer to the Kubernetes Operator pattern.