OpenNebula

Early on, the documentation on setting up and installing says "Additionally you should be able to ssh passwordlessly to all the hosts (including itself, the frontend) from the frontend." This is from the page Planning the Installation 4.2 (http://opennebula.org/documentation:rel4.2:plan) and instructions to this effect occur several times. These sound like instructions to create such an account.

However, the specifics of the account to use, and constraints on that account, come later. The wording mentioned above should be something like "Additionally you will need to create accounts on each machine that can ssh passwordlessly to all the hosts (including itself, the frontend) from the frontend. Details and constraints on creation of these accounts is given in the Installing the Software [http://opennebula.org/documentation:rel4.2:ignc#user_group_unix_accounts_front-end_hosts] guide."