Vertica NODE/Cluster hardening

https://www.vertica.com/blog/building-secure-vertica-environment/

Hi Jim, thanks for your answer - I saw this - but this is security breach mitigation risk on DB level. I was asking about OS level Hardening (sorry for not being precise enough). Like blocking root access/sudo, closing ports (other than specified documentation), stronger file permission (group, user level only - etc)