Developing an application for a multi-client-installation isn’t only a technical or engineering quest, but also reveals some question, which affect administration and organisationial processes.
To ease administration, the user accounts in CQ are often organized in a hiearchy, so that users which are placed higher in the hierarchy, can administrate user which are lower in the hierarchy tree below them. Using this mechanism a administrator can easily delegate the administration of certain users to other users, which can also do adminstrative works for “their” users.
The problem arises when a user has to have rights in 2 applications within the same CQ instance and every application should have its own “application administrator” (a child node to the superuser user). Then this kind of administration is no longer possible, because it is impossible to model a hierarchy where neither application administrator user A has a parent or child relation to application administration user B nor A and B are placed in the hierarch higher than any user C.
I assume that creating accounts for different application but the same person isn’t feasible. That would be the solution which the easiest one from an engineering point of view, but this does contradict the ongoing move not to create for each application and each user a new user/password pair (single sign on).
This problem imposes the burden of user administration (e.g assigning users to groups, resetting passwords) to the superuser, because the superuser is the user, which is always (either by transition or directly) parent to any user. (A non-CQ-based solution would be to handle user related changes like password set/reset and group assignment outside of CQ and synchronize these data then into CQ, e.g. by using a directory system based on LDAP.)
ACLs, access to templates and workflows should be assigned only using groups and roles, because these can be created per application. So if an application currently is based on a user hierarchy and individual user rights it’s hard to add a new application using the same user.
So one must make sure, that all assignments are only based on groups and roles, which are created per application. Assigning individual rights to a single user isn’t the way to go.