The CUE Zipline cores communicate with each other via private network connections, using the network addresses defined in the members list configured in the cluster configuration object.


The members list is a list of host name and port pairs for each instance in the cluster. Each instance opens connections to the other instances by connecting to these network addresses.

The network address of each instance is defined by the listen_address property of the cluster configuration object. The listen address may be specified as a wild-card (e.g. in order to listen on all network interfaces.

The port number of the cluster listen_address must be different from the server port number, because the communication protocol is different. By default, the server port is 12791 and the cluster listen address port is 12790.

The host names and addresses specified in the members list may not be specified as wild cards. They must be host names that can be resolved or IP addresses, and they must be accessible to the other instances in the cluster.