Development
TyKO aims to follow the Kubernetes Operator pattern and is relying on Operator SDK Framework for the undelying technical nuances and scaffolding. It uses Controllers, which provide a reconcile function responsible for synchronizing resources until the desired state is reached on the cluster. That said, contributing to or further developing TyKO, requires moderate experience in Golang & Kubernetes and basic exposure to concepts like operators, controllers, state reconcilition, custom resource definitions.
For a deeper understanding of developing operators in Golang, you can consult either the Quickstart for Go-based Operators of Operator SDK or the Kubebuilder Book (Operator SDK is using Kubebuilder under the bonnet).
Changing the CRDs
To extend the CRD, update the file api/v1alpha1/typesensecluster_types.go. Then, to apply your changes, run:
make generate && make manifests
Installing the CRDs
After every change, you have to install or update the new schema of the CRDs in your target cluster. This can be accomplished by:
make install
Running the Controller
You can run the controller, out-of-cluster, as a normal process in your development machine with:
make run
No manager Pod will be created in your cluster. Remember, we are running with make run the manager as a local process in our machine. As the controller needs to be able to access individual pods to probe their health status as quorum members we resort to building a VPN with our target cluster. Read more in Debugging
Debugging
When debugging from your IDE of choice (or running the controller out-of-cluster with make run) all health and status requests to individual pods will fail, as the node endpoints are not available to your development machine. For that matter, you will need to deploy KubeVPN in your environment. KubeVPN, offers a cloud-native development environment that connects to your Kubernetes cluster network. It facilitates the interception of inbound traffic from remote Kubernetes cluster services or pods to your local machine so you can access them using either their Kubernetes-internal FQDN or IP address.
After deploying KubeVPN, create the VPN connection with your Kubernetes cluster with:
kubevpn connect
and you can disconnect any moment with:
kubevpn disconnect 0
For more information consult the official documentation of KubeVPN.