Sometimes the Gmond process does not start and spews the following error.
gmond -d 10
udp_recv_channel mcast_join=10.16.101.81 mcast_if=NULL port=8664 bind=10.16.101.81
Error creating multicast server mcast_join=10.16.101.81 port=8664 mcast_if=NULL family='inet4'. Exiting.
This happens due to some multicast routing issues. I am not sure exactly what is causing this problem. The fix is to explicitly add a route.
route add -host 18.104.22.168 dev eth0
Need to learn what is causing this problem though..