The Hadoop default security model without Kerberos

Now that we understand how the Kerberos security protocol works, let us look at the details of the Hadoop default security model and its limitations.

Hadoop implements a security model similar to the POSIX filesystem, which gives the ability to apply file permissions and restrict read-write access to files and directories in HDFS. The user and admin can use the chmod and chown commands to change the permissions and ownership of the file/directories, similar to the POSIX filesystem. Hadoop does not provide any user management functionality. It uses the operating system user within Hadoop.

By default, Hadoop doesn't support any authentication of users or Hadoop services. A user only authenticates with the operating system during the logon process. After that, when the user invokes the Hadoop command, the user ID and group is set by executing whoami and bash -c groups respectively. So if a user writes their own whoami script and adds it to the...