怎样配置emqtt cluster的配置项

关于emqtt 集群的配置，配置文件中的配置项，都是指什么意思，怎样填写。

Cluster with multicast
cluster.mcast.addr = 239.192.0.1

cluster.mcast.ports = 4369,4370

cluster.mcast.iface = 0.0.0.0

cluster.mcast.ttl = 255

cluster.mcast.loop = on

cluster.discovery = dns

Cluster with DNS
cluster.dns.name = localhost

cluster.dns.app = ekka

cluster.discovery = etcd

Cluster with Etcd
cluster.etcd.server = http://127.0.0.1:2379

cluster.etcd.prefix = emqcl

cluster.etcd.node_ttl = 1m

cluster.discovery = k8s

Cluster with k8s
cluster.k8s.apiserver = http://10.110.111.204:8080

cluster.k8s.service_name = ekka

Address Type: ip | dns
cluster.k8s.address_type = ip

The Erlang application name
cluster.k8s.app_name = ekka