How to enable unicast on Ganglia

To configure unicast you should designate one machine to be receiver. Receiver's gmond.conf should look like this

globals {
  daemonize = yes
  setuid = yes
  user = nobody
  debug_level = 0
  max_udp_msg_len = 1472
  mute = no
  deaf = no
  allow_extra_data = yes
  host_dmax = 86400 /* Remove host from UI after it hasn't report for a day */
  cleanup_threshold = 300 /*secs */
  gexec = no
  send_metadata_interval = 30 /*secs */
}

cluster {
  name = "Production"
  owner = "unspecified"
  latlong = "unspecified"
  url = "unspecified"
}

host {
  location = "unspecified"
}

udp_send_channel {
  host = ip.add.ress.here
  port = 8649
  ttl = 1
}
udp_recv_channel { 
  port = 8649
}

tcp_accept_channel {
  port = 8649
}

.....

On all the other machines you will need to configure only this

globals {
  daemonize = yes
  setuid = yes
  user = nobody
  debug_level = 0
  max_udp_msg_len = 1472
  mute = no
  deaf = yes
  allow_extra_data = yes
  host_dmax = 86400 /* Remove host from UI after it hasn't report for a day */
  cleanup_threshold = 300 /*secs */
  gexec = no
  send_metadata_interval = 30 /*secs */
}

cluster {
  name = "Production"
  owner = "unspecified"
  latlong = "unspecified"
  url = "unspecified"
}

host {
  location = "unspecified"
}

udp_send_channel {
  host = ip.add.ress.here
  port = 8649
  ttl = 1
}
...

Please notice that send_metadata_interval is set to 30 (seconds). Metrics in Ganglia are sent separately from it's metadata. Metadata contains information like metric group, type etc. In case you restart receiving gmond metadata will be lost and gmond will not know what to do with the metric data and it will be discarded. This may result in blank graphs. In multicast mode gmonds can talk to each other and will ask for metadata if it's missing. This is not possible in unicast mode thus you need to instruct gmond to periodically send metadata.

Now in your gmetad.conf put

# /etc/gmetad.conf on ip.add.ress.here
data_source "Production" ip.add.ress.here

...

Now restart everything...