consul:健康检查
官方文档:https://www.consul.io/docs/agent/checks.html
consul提供的健康检查有以下几种:
1、script+interval
2、http+interval
3、tcp+interval
4、time to live
5、docker+interval
6、grpc+interval
https://github.com/grpc/grpc/blob/master/doc/health-checking.md
7、alias