It complains if the source is not specified in the flume configuration. I have another kafka producer writing to kafka topic (so I don't the source in flume configuration) and would like just to read those messages in flume (with kafka channel and hdfs sink).
you're right. On CDH 5.14 it's just a warning. Thanks !
Just one more question - if the topic in kafka channel has three partitions, is it expected that flume hdfs sink will allocate three separate files on HDFS?