The following examples use these addresses:
Munin server: 192.184.94.230 (ramnode.advanxer.com)
Munin node 1: 192.210.208.175 (bluevm.advanxer.com)
Munin node 2: 54.254.177.162 (ec2.advanxer.com)

Server side configuration
/etc/munin/munin.conf
htmldir /usr/share/nginx/www/munin
# a simple host tree
[ramnode.advanxer.com]
address 127.0.0.1
use_node_name yes

[bluevm.advanxer.com]
address 192.210.208.175
use_node_name yes

[ec2.advanxer.com]
address 54.254.177.162
use_node_name yes
# port 4950

Munin node configuration
/etc/munin/munin-node.conf
host_name vps.advanxer.com
allow ^192\.184\.94\.230$

Force node update: su - munin /usr/share/munin/munin-update
Look for update activity at /var/log/munin/munin-update.log

Reference:
http://www.mbse.eu/linux/homeserver/mgmt-maint/munin/
http://munin-monitoring.org/wiki/munin.conf
http://docs.mongodb.org/ecosystem/tools/munin/