When a node is brought online, it uses multicast discovery to learn about other nodes. You can see the gist here: https://github.com/nanopack/mist/blob/master/main.go#L68-L76

Propagating events is really simple: When a client subscribes to a particular node, the node will replicate the subscription to all nodes in the cluster, and relay any messages from the 'proxied' subscriptions back to the client.

Also, if your network can't natively support multicast, you might want to check out red (https://github.com/nanopack/red) "A fast, in-kernel, ad-hoc point-to-point vxlan network."