In other words, Oracle Cluster is asking you to make your OS insecure first. :-)
Here are steps for you how to fix the issue (saves you a half of a day):
1. Modify /etc/user_attr file.
2. Comment out line CONSOLE=/dev/console in /etc/default/login file.
Why? Read the description there.
3. Allow remote login for root in SSH daemon by editing /etc/ssh/sshd_config file.
4. Restart SSH daemon by issuing the following command:
# svcadm restart /network/ssh
5. Set password for root:
# passwd root
6. Generate SSH keys:
# ssh-keygen -t rsa
Phew! Now you can put your public SSH keys elsewhere and enjoy
Snorcle Fustercluck Oracle Cluster installation (as an example). :-)