编写配置文件时要注意语法，如新版本的logstash对参数host变更为hosts，去除了port参数等。

[root@localhost logstash]# cat logstash_agent.conf input {    file {        type => "messages"        path => ["/var/log/messages"]    }}output {    elasticsearch {        hosts => "192.168.96.128"    }}