Extending Kubernetes

External

• https://kubernetes.io/docs/concepts/extend-kubernetes/extend-cluster/

Internal

• Kubernetes Development
• Kubernetes Concepts

Custom Resource

Custom Resource Definition (CRD)

https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/custom-resources/

https://github.com/kubernetes-sigs/kubebuilder

Extension API Server

• https://github.com/kubernetes-sigs/apiserver-builder-alpha
• https://kubernetes.io/docs/tasks/extend-kubernetes/setup-extension-api-server/
• https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/apiserver-aggregation/

Differences between CRDs and Extension API Servers

• An extension API server can use different storage APIs rather than etcdv3
• Extends long-running subresources/endpoints like websocket for your own resources
• Integrates your apiserver with whatever external systems

Operator Pattern

• https://kubernetes.io/docs/concepts/extend-kubernetes/operator/