需求：
kibana监控elasticsearch+kibana+logstash的性能寻找，性能瓶颈！
发现启动logstash加载logstash.yml，不读取配置好的xpack.monitoring.elasticsearch.url: "xxx"的值，而读取的系统默认的"http://localhost:9200"实例进行健康监测！，搞得懵逼了！，搞了好几天最后发现问题了，yaml语言的语法，开启的选项必须对齐。
简单的elk架构
错误日志：
[ERROR][logstash.licensechecker.licensemanager] Unable to retrieve license information from license server {:message=>"Elasticsearch Unreachable: [http://localhost:9200/][Manticore::SocketException] Connection refused",
解决方案：
查看logstash.yml,对开启的参数需要对齐，方才读取参数的值！
[root@DZSWJ_NRGL config]# egrep -v "^#|^$" logstash.yml
node.name: node-lg-xxx.xxx
pipeline.workers:
pipeline.batch.size:
pipeline.batch.delay:
http.host: "xxx.xxx.xxxx.xxx"
http.port: ""
log.level: warn
xpack.monitoring.elasticsearch.url: "http://xxx.xxx.xxx.xxx:9200"
xpack.monitoring.elasticsearch.username: "logstash_system"
xpack.monitoring.elasticsearch.password: ""