* 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__)
* node-exporter exposes metrics to Prometheus about total and
active md devices (e.g. disks in mdadm RAID arrays)
* Add alert that fires when a RAID disk fails or becomes inactive
for another reason
* 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
* A data volume (emptyDir) is mounted to /var/lib/prometheus
* Users could swap emptyDir for any desired volume if data
persistence is desired. Prometheus previously defaulted to
keeping its data in ./data relative to /prometheus. Override
this behavior to store data in /var/lib/prometheus
* Expose etcd metrics to workers so Prometheus can
run on a worker, rather than a controller
* Drop temporary firewall rules allowing Prometheus
to run on a controller and scrape targes
* Related to https://github.com/poseidon/typhoon/pull/175
* 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
* Annotate Prometheus service to scrape metrics from
Prometheus itself (enables Prometheus* alerts)
* Update kube-state-metrics addon-resizer to 1.7
* Use port 8080 for kube-state-metrics
* Add PrometheusNotIngestingSamples alert rule
* Change K8SKubeletDown alert rule to fire when 10%
of kubelets are down, not 1%
* https://github.com/coreos/prometheus-operator/pull/1032
* Deployments now belong to the apps/v1 API group
* DaemonSets now belong to the apps/v1 API group
* RBAC types now belong to the rbac.authorization.k8s.io/v1 API group
* 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
* Adapt the coreos/prometheus-operator alerting rules for Typhoon,
https://github.com/coreos/prometheus-operator/tree/master/contrib/kube-prometheus/manifests
* Add controller manager and scheduler shim services to let
prometheus discover them via service endpoints
* Fix several alert rules to use service endpoint discovery
* A few rules still don't do much, but they default to green
