This is a sample standalone cluster configuration from config.json:

"clusters": {
    "north": {
        "host":"localhost",
        "port":"8203"
    }
},

This is a sample composite cluster configuration from config.json (either active/passive or active/active):

"clusters": {
    "global": {
        "host":"localhost",
        "port":8201,
        "children": [ "west","east" ]
    },
    "east": {
        "host":"localhost",
        "port":"8202",
        "memberOf":"global"
    },
    "west": {
        "host":"localhost",
        "port":"8203",
        "memberOf":"global"
    }
},