Hi all!
tl;dr newly created files in HDFS will not be 'world' readable by default. I.e. you must be either the owner or in the file's group to read the file.
Today we changed the default HDFS umask to 027, so that all new files and dirs will have either 640 (rw-r-—--) (for files) or 750 (rwx-r-x-—) for directories.
We don't anticipate any problems, but if you encounter any please don't hesitate to let us know. You can always hdfs dfs -chmod your files after you create them.
Your friendly Hadoop operators,
- Andrew & Razzi & Luca