The krb5-server package should be removed if not in use.
Is this system the Kerberos server? If not, remove the package.
The krb5-server package can be removed with the following command:
$ sudo yum erase krb5-server
The krb5-server RPM is not installed by default on a Oracle Linux 7
system. It is needed only by the Kerberos servers, not by the
clients which use Kerberos for authentication. If the system is not
intended for use as a Kerberos Server it should be removed.