There has been an increasing demand from users to be able to manage the health, status, rollout, rollback, etc., of CoreDNS in a Kubernetes cluster; and not just rely on CoreDNS being managed by the cluster management tools. Since the use of Operators in Kubernetes is now generally accepted, the aim of the cluster-addons project is to bring the benefit of Operators to all addons.
Addons extend the functionality of Kubernetes. Some of the addons, like CoreDNS and kube-proxy, are considered essential to the functionality of a Kubernetes cluster and are shipped along with cluster management tools like Kubeadm, Kops, etc. There are other addons which can be installed as an option and are not as critical, but help users manage their clusters — e.g., Calico, Kubernetes Dashboard, and NodelocalDNS.
The purpose of the cluster-addons project is to enable you to manage addons in a better way, with the help of Operators.