federation, which is not supported in the version we have source to.
Basically, we run an elvind on each node. The proxy on each node
subscribes to all events for that node from the boss elvind, and hands
them to the local elvind, Each client on the node subscribes to the
local elvind, and gets its events via the proxy. This should reduce
the number of connections to boss, and makes it possible to run agents
inside each virtual node without an FD explosion on boss.