chmod 777 prometheus.yml
启动问题报错：
level=error ts=2018-11-19T06:01:05.697957445Z caller=main.go:625
err="opening storage failed: lock DB directory: resource temporarily unavailable
解决：删除 lock 文件
rm -f /usr/local/prometheus/prometheus215/data/lock
启动问题：
level=error ts=2018-11-19T06:04:47.83421089Z caller=main.go:625
err="error starting web server: listen tcp 0.0.0.0:9090: bind: address already in use"
解决：查找使用 9090 端口的 PID 并删掉
ps -ef|grep 9090
Kill -9 pid 号
