Cellar events should include all the information required for the processing of the event.

When an event is processed in Cellar most of the time a lookup to the distributed registry is required.

I can see a couple of issues with this approach:
i) Unnecessary access to the distributed resources.
ii) The state of the group is only in memory and is not persisted anywhere.
iii) Having the state in the distributed memory its not easy to view the state of a group.

I think that we should not use distributed memory as registry at all. Each event should contain all the information required for its processing and those information should be persisted locally on each node (configuration admin / fileinstall).

The only thing that maybe needs to be addressed, is what happens when a new node joins a group. I am thinking that it should not be really hard to send something like "request group config" command and then just process the result.