logstash配置如何理解？

1. elasticsearch {
2.  
   action => "index" #The operation on ES
3.  
   hosts => "localhost:9200" #ElasticSearch host, can be array.
4.  
   index => "applog" #The index to write data to.
5.  
   }

   在logstash中需要配置的elasticsearch其中action配置和index配置具体是什么意思？后面的解释也不懂，哪位知道，请用大白话解释一下呗