When you run 'mosmon', press 't' to see the total number of machines running. Does it warn you that openMosix is not running?
If it does, then make sure your machine's IP address is included in /etc/openmosix.map. Don't use 127.0.0.1. If you do, you will probably have problems with your DHCP server or your DNS nameserver.
If it does not, then see what machines show up. Do you see only your machine?
If yes, then your machine is most likely running a firewall and is not letting openMosix through.
If not, then the problem is most likely with the machine that doesn't show up.
Also: Do you have two NIC cards on a node? If so, you have to edit /etc/hosts to have a line that has the following format
<non-cluster ip> <cluster-hostname>.<cluster-domain> <cluster-hostname>
Maybe you used different kernel-parameters on each machine? Especially if you use the 'Support clusters with a complex network topology' option you should take care that you use the same value for the also appearing option 'Maximum network-topology complexity support' on each machine.
They represent three stages of Mosix/openmosix growth. The file /etc/mosix.map is the orginal Mosix map name, The file /etc/hpc.map was an early openMosix map name (and 'hpc' is still used for the /proc files in openMosix). The current map name is /etc/openmosix.map.
You'll need to modify your /etc/hosts file. On Red Hat machines mostly the /etc/hosts file includes a line like
127.0.0.1 hostname.domain.com localhost
If hostname.domain.com has an IP address of 192.168.10.250, and if you looked up hostname.domain.com you might get 127.0.0.1 as an answer.
However, if you put
192.168.10.250 hostname.domain.com 127.0.0.1 localhost
A machine is never too weak: I have three P200s (64MB each) and two P166s (one with 48MB and one with 192MB). Two of them are on 10Base-T and the other three on 100Base-T. Even with these antiquated machines and "heterogenous" network, I get perfect load balancing to run simulation programs that I write in Perl. (Look at our ProgramToTestACluster"). Don't be held back by the fact your machines are old. To us this is a nice feature of openMosix: you can add newer machines to an existing cluster as they become available. And you do not need to have all identical machines. That's fantastic!
However, a 100Base-T network is recommended! Contributed by Charles Nadeau.
If you intend to run VMWare under openMosix so that openMosix would load-balance several instances of that (yes, that works). But, if you want to run openMosix in several VMWare instances and let these instances load balance (that fails).
The first case works. The latter case does not work because VMware has a bug in its Pentium emulation that makes VMware crash (not openMosix, but the VMware binary) on the first migration.
Only IA-32 is currently supported. The port of openMosix to the Intel(r) Itanium(tm) IA-64 Processor Family is complete. Project plans for openMosix' second year include porting to the 64-bit AMD Opteron(tm) processor.