So when you make a call to port 15984 on a Kazoo box, what's really happening is haproxy is running on that machine and it will proxy that request to port 5984.
HAPROXY will often proxy your request to a different server then you made the call to. That's the HA part. High Availability.
https://groups.google.com/forum/#!searchin/2600hz-dev/zone/2600hz-dev/3m2C374mKbg/VUTEsJjrSHEJ
Zone 1 - Customer/Region
listen bigcouch-data 127.0.0.1:15984
balance roundrobin
server db1.zone1.mydomain.com 127.0.0.1:5984 check
server db2.zone1.mydomain.com 127.0.0.2:5984 check
server db3.main.mydomain.com 127.0.0.3:5984 check backup
server db4.main.mydomain.com 127.0.0.4:5984 check backup
Zone 2 - Customer/Region
listen bigcouch-data 127.0.0.1:15984
balance roundrobin
server db1.zone2.mydomain.com 127.0.0.1:5984 check
server db2.zone2.mydomain.com 127.0.0.2:5984 check
server db3.main.mydomain.com 127.0.0.3:5984 check backup
server db4.main.mydomain.com 127.0.0.4:5984 check backup