In HDFS, you view a file with rw-r–r– set as its permissions. What does this tell you about the file?

A.
The file cannot be deleted by anyone but the owner

B.
The file cannot be deleted by anyone

C.
The file cannot be run as a MapReduce job

D.
The file’s contents can be modified by the owner, but no-one else

E.
As a Filesystem in Userspace (FUSE), HDFS files are available to all user’s on a cluster
regardless of their underlying POSIX permissions.

Explanation:
The owner has rw- permissions (read and write). Only he can deletethe file.
Note:
Starting with Hadoop 0.16.1, HDFS has included a rudimentary file permissions system. This
permission system is based on the POSIX model, but does not provide strong security for HDFS
files. The HDFS permissions system is designed to prevent accidental corruption of data or casual
misuse of information within a group of users who share access to a cluster. It is not a strong
security model that guarantees denial of access to unauthorized parties.
HDFS security is based on the POSIX model of users and groups. Each file or directory has 3
permissions (read, write and execute) associated with it at three different granularities: the file’s
owner, users in the same group as the owner, and all other users in the system. As the HDFS
does not provide the full POSIX spectrum of activity, some combinations of bits will be
meaningless. For example, no file can be executed; the +x bits cannot be set on files (only

directories). Nor can an existing file be written to, although the +w bits may still be set.
Security permissions and ownership can be modified using the bin/hadoop dfs -chmod, -chown,
and -chgrp operations described earlier in this document; they work in a similar fashion to the
POSIX/Linux tools of the same name.
Reference:
HDFS Permissions and Security