https://zhuanlan.zhihu.com/p/43637757
https://www.cnblogs.com/xiangsikai/p/11289966.html
dashboard sub-folder
Prometheus exporter custom data types: https: //prometheus.io/docs/concepts/metric_types/
Value types can only float, not as a text: https: //github.com/prometheus/prometheus/issues/2227
Custom exporter:
https://songjiayang.gitbooks.io/prometheus/content/exporter/sample.html
prometheus pod collection where the node root disk footprint:
https://github.com/coreos/prometheus-operator/issues/677
promql