Prometheus Operator vs. kube-prometheus
The Prometheus Operator makes the Prometheus configuration Kubernetes native and manages and operates Prometheus and Alertmanager clusters. It is a piece of the puzzle regarding full end-to-end monitoring.
kube-prometheus combines the Prometheus Operator with a collection of manifests to help getting started with monitoring Kubernetes itself and applications running on top of it.
https://github.com/coreos/prometheus-operator/tree/master/contrib/kube-prometheus