* Prometheus queries from some upstreams use joins of node-exporter
and kube-state-metrics metrics by (namespace,pod). Add the Kubernetes
pod name to service endpoint metrics
* Rename the kubernetes_namespace field to namespace
* Honor labels since kube-state-metrics already include a `pod` field
that should not be overridden
* Kubelet uses a node's hostname as the node name, which isn't
resolvable on DigitalOcean. On DigitalOcean, the node name was
set to the internal IP until #337 switched to instead configuring
kube-apiserver to prefer the InternalIP for communication
* Explicitly configure etcd scrapes to target each controller by
internal IP and port 2381 (replace __address__)
* Use Kubelet bearer token authn/authz to scrape metrics
* Drop RBAC permission from nodes/proxy to nodes/metrics
* Stop proxying kubelet scrapes through the apiserver, since
this required higher privilege (nodes/proxy) and can add
load to the apiserver on large clusters
* Use etcd v3.3 --listen-metrics-urls to expose only metrics
data via http://0.0.0.0:2381 on controllers
* Add Prometheus discovery for etcd peers on controller nodes
* Temporarily drop two noisy Prometheus alerts
* Change service discovery to relabel jobs to align with
rule expressions in upstream examples
* Use a separate service account for prometheus instead
of granting roles to the namespace's default
* Use a separate service account for node-exporter
* Update node-exporter and kube-state-metrics exporters
