Fuse 7 generic implementation of ESB

I'm working for a client who is implementing Fuse as their central ESB. At the moment it is Fuse version 6.3, but the plan is to move on to Fuse & and OpenShift. It is intentended that we implement several instances of the ESB supporting specific areas of the application landscape (as so called domain busses)
What I would like to know is to what level a generic ESB can be defined and at what level specific choices have to be made. As an exemple: persistency is defined at the level of message brokers and that implies that all ESB's that make use of those brokers will have persistent messaging. The same may go for certain security settings, but that might very well vary between ESB's (and their respective containers).
To summarize: can someone provide me with an overview on the several layers concerning an implementation of Fuse ESB in OpenShift (hardware layer, datalayer, transport layer etc) and which features are "fixed" to which layer.
Thanks in advance.
Lodewijk