The auto-discovery daemon (omdiscd) provides a way to automatically configure an openMosix cluster hence eliminating the need of a /etc/mosix.map or similar manual configurations. Auto-discovery uses multicast packages to notify other nodes that it is an openMosix node. This way adding an extra node to your mosix cluster means that you just have to start the omdiscd on your machine and it will join the cluster. However there are some small requirements, Like with any openMosix cluster , you need to have networking configured correctly. mainly the routing. Without a default route, you must specify an interface to omdiscd with the -i option. Otherwise omdiscd will exit with an error like. Aug 31 20:41:49 localhost omdiscd[1290]: Unable to determine address of default interface. This may happen because there is no default route configured. Without a default route, an interface must be: Network is unreachable Aug 31 20:41:49 localhost omdiscd[1290]: Unable to initialize network. Exiting. An example of a correct routing is below [root@localhost log]# route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 10.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 eth0 127.0.0.0 0.0.0.0 255.0.0.0 U 0 0 0 lo 0.0.0.0 10.0.0.99 0.0.0.0 UG 0 0 0 eth0 Basically from now on everything will get easier. Just start omdiscd And have a look at your logfiles you should see something similar to this Sep 2 10:00:49 oscar0 kernel: openMosix configuration changed: This is openMosix #2780 (of 6 configured) Sep 2 10:00:49 oscar0 kernel: openMosix #2780 is at IP address 192.168.10.220 Sep 2 10:00:49 oscar0 kernel: openMosix #2638 is at IP address 192.168.10.78 Sep 2 10:00:49 oscar0 kernel: openMosix #2646 is at IP address 192.168.10.86 Sep 2 10:00:49 oscar0 kernel: openMosix #2627 is at IP address 192.168.10.67 Sep 2 10:00:49 oscar0 kernel: openMosix #2634 is at IP address 192.168.10.74 Congratulations , your openMosix cluster is now working. omdiscd has some other options that you can use. You can either run omdiscd as a daemon (default) or in the foreground where output goes to the screen (standard output) omdiscd -n . An interface can be specified with the -i option. Now lets still have a short look at the other tool , it's showmap. This tool will show you the newly auto generated openMosix map. [root@oscar0 root]# showmap My Node-Id: 0x0adc Base Node-Id Address Count ------------ ---------------- ----- 0x0adc 192.168.10.220 1 0x0a4e 192.168.10.78 1 0x0a56 192.168.10.86 1 0x0a43 192.168.10.67 1 0x0a4a 192.168.10.74 1 Auto-discovery has some other features not listed here such as a routing mechanism for clusters with more than one network. More detailed information can be found in the README and DESIGN files in the user-land tools source tree. More recent versions of the openMosix rc scripts will first verify wether an /etc/openmosix.map file or similar exists before trying to use autoconfiguration. If you are compiling autodiscovery from source you will need to make a small modification to openmosix.c. One of the first lines will be #define ALPHA You will need to put this in comment. If you want to have some more logging available to you, you should edit main.c to show log_set_debug(DEBUG_TRACE_ALL); (somewhere around line 84) now run % make clean % make Sometimes however autodiscovery does not function as you would like, for example a node might not see multicast traffic from other nodes. This has occurred with some PCMCIA ethernet drivers. One solution is to place the interface in promiscuous and or multicast mode as detailed below: Aug 31 20:45:58 localhost kernel: openMosix configuration changed: This is openMosix #98 (of 1 configured) Aug 31 20:45:58 localhost kernel: openMosix #98 is at IP address 10.0.0.98Aug 31 20:45:58 localhost omdiscd[1627]: Notified kernel to activate openMosix Aug 31 20:45:58 localhost kernel: Received an unauthorized information request from 10.0.0.99 What you should to then is try to force your NIC into promiscuous and/ or multicast mode manually. ifconfig ethx promisc or ifconfig ethx multicast You might also want to run tcpdump -i eth0 ether multicast which will have the same effect but you will now also be able to see the packages yourself. On some Layer 3 switches you other configs might be required. An openMosix user found out that on his Switch Summit48Si (Extreme Networks) he had to run disable ipmcforwarding (to deactivate the routing of multicast paquets) disable igmp snooping before he was the different omdiscd's were able to see eachother, other switches might require similar configs. Aug 31 22:14:43 inspon omdiscd[1422]: Simulated notification to activate openMosix [root@inspon root]# showmap My Node-Id: 0x0063 Base Node-Id Address Count ------------ ---------------- ----- 0x0063 10.0.0.99 1 [root@inspon root]# /etc/init.d/openmosix status OpenMosix is currently disabled [root@inspon root]# If you see the simulated you have probably forgotten to put the #define ALPHA in comment. I have also noticed that autodiscovery does not work with FireWire based network cards.