Hi, I have been trying to install ganglia on my 13-node cluster and had it all working wonderfully and was amazed how easilly until I restarted my firewall :)
I use APF which sits on top of IPTables and as soon as I start it ganglia just stops communicating with the rest of the world. All IPs that are involved in the cluster are allowed to communicate on any port/protocol but there is something not right. I can "telnet ip 8649" from the master to the nodes and I get the XML data absolutly fine but for some reason the master just is not connecting. I am also completly confused about the whole multicasting thing - I dont think I want it but I tried to just use unicast to no avail. What I really want is either some hints on setting up unicast (with one "master" connecting to the 13 slaves every 20 seconds or so and downloading the XMl data), or instructions on IPTables rules for multicasting (I have tried adding iptables -A INPUT -d 224.0.0.0/4 -j ACCEPT iptables -A OUTPUT -d 224.0.0.0/4 -j ACCEPT which was the only suggestion I could find in the archive, to no avail). With many thanks, Alex Davies