What does UNLINK event mean in hdfs inotify api?

[#1]

Hi guys, I am working on writing a hdfs hook, yet I am not quite understand what does unlink event do, I found on this presentation that the delete log would be captured as a unlink event, but when I run a

hadoop fs -rm /h.txt 

command, the unlink event is not captured? So what kind of hdfs commands would capture this unlink event ?

[#2 · Accepted solution]

@Qinglin Xia

You might be interested in the Nifi GetHDFSEvents processor.

https://nifi.apache.org/docs/nifi-docs/components/org.apache.nifi.processors.hadoop.inotify.GetHDFSE...

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I personally did not check the UNLINK event though but i see a good example to validate the same. I try it you also might want to check the same in parallel:

https://github.com/onefoursix/hdfs-inotify-example/blob/master/src/main/java/com/onefoursix/HdfsINot...

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[#3]

Thanks I found those examples and run them already, but still not quite understand what unlink event do, also how the inotify works? Do you know any documentations explaining the inotify api?

[#4]

Finally got it, the delete op in hdfs should correspond to the rename event, coz hdfs would move the removed files/dirs to the trash file first