我对 flume 中的以下三个水槽配置非常困惑。请澄清我
会议1
a1.sinks.k1.type = hdfs
a1.sinks.k1.hdfs.path = /flume/events/
会议2
a1.sinks.k1.type = hdfs
a1.sinks.k1.hdfs.path = hdfs://localhost:9000/flume/events/
会议3
a1.sinks.k1.type = file_roll
a1.sinks.k1.sink.directory = /var/log/flume
每个接收器的具体用例是什么?