If you’re trying to upload to HDFS using the filebrowser in Hue, and encounter an unknown error in the Hue UI, but the error logs for the cherrypy server indicate:
upload ERROR Not using HDFS upload handler: <urlopen error [Errno -2] Name or service not known>
Then it’s likely that the file is being uploaded to the HDFS tmp directory, but then Hue is unable to access the file directly through one of the datanode’s webhdfs API.
Ensure that your hue server can connect to each datanode on port 50075 by its DNS name.