zookeeper | eMQTT1 eMQTT2 eMQTT3 Bridge eMQTT1 --> eMQTT2 Cluster eMQTT1 <--> eMQTT2 Cluster and Bridge eMQTT1 eMQTT3 ----> eMQTT2 eMQTT4 Mnesia Cluster