How to implement RBAC in multiple databases?

Hey guys,

I'm researching about the necessity of providing data access to users in multiple databases context. In reality, I'm looking for what could be done to make things easier, and if things need to be easier in the first place.

1. How do you deal with having to create/maintain a lot of users in different databases?

2. What about updating their permissions?

3. What about the granularity of those permissions?

4. Do you find it difficult?

5. Is there any solution to solve this in a 'plug and play' manner?

Thanks in advance for the input!