HDFS permissions determine what a user can do to files and directories stored in HDFS. To access a file or directory, a user must have permission or belong to a group that has permission.
HDFS permissions are similar to permissions for UNIX or Linux systems. For example, a user requires the
r
permission to read a file and the
w
permission to write a file.
When a user or application attempts to perform an action, HDFS checks if the user has permission or belongs to a group with permission to perform that action on a specific file or directory.