Securing kube-controller-manager

kube-controller-manager manages the control loop for the cluster. It monitors the cluster for changes through the API server and aims to move the cluster from the current state to the desired state. Multiple controller managers are shipped by default with kube-controller-manager, such as a replication controller and a namespace controller. Compromise of kube-controller-manager can result in updates to the cluster being rejected.

To secure kube-controller-manager, you should use --use-service-account-credentials which, when used with RBAC ensures that control loops run with minimum privileges.

On Minikube, the kube-controller-manager configuration looks like this:

$ps aux | grep kube-controller-manager
root      3927  1.8  4.5 209520 90072 ?        Ssl  01:03   0:11 kube-controller-manager --authentication-kubeconfig=/etc/kubernetes...