Metrics information extract

[Esonhugh]

Metrics service like kube-metrics will expose a service to let Prometheus to know how the node / cluster works.

Its information is useful.

Current Idea is using grok expression to extract useful information about the cluster.

What's grok expression?

Grok is a regular expression dialect that supports reusable aliased expressions. Grok works really well with syslog logs, Apache and other webserver logs, mysql logs, and generally any log format that is written for humans and not computer consumption.

https://www.elastic.co/guide/en/elasticsearch/reference/current/grok.html

it's working the branch feat/kube-metrics