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4.5. Red Hat and openMosix

If you are running a RedHat 7.2, 7.3 or 8.0 version, this is probably the easiest *Mosix install you have ever done. Choose the appropriate openMosix RPMs from sourceforge. They have precompiled kernels (as I write this 2.4.20) that work seamlessly: I have tested them on several machines including Laptops with PCMCIA cards and Servers with SCSI disks. If you are a grub user, the kernel rpm even modifies your grub.conf. So all you have to do is install 2 RPMs:

rpm -Uvh openmosix-kernel-2.4.20-openmosix2.i686.rpm openmosix-tools-0.2.4-1.i386.rpm
and edit your /etc/openmosix.map if you don't wish to use the autodiscovery daemon (omdiscd). Since this seems to be a problem for lots of people, let's go with another example. Say you have 3 machines: 192.168.10.220, 192.168.10.78 and 192.168.10.84. Your openmosix.map will look like this.
[root@oscar0 root]# more /etc/openmosix.map 
# openMosix CONFIGURATION
# ===================
#
# Each line should contain 3 fields, mapping IP addresses to openMosix node-numbers:
# 1) first openMosix node-number in range.
# 2) IP address of the above node (or node-name from /etc/hosts).
# 3) number of nodes in this range.
#
# Example: 10 machines with IP 192.168.1.50 - 192.168.1.59
# 1        192.168.1.50     10
#
# openMosix-#  IP  number-of-nodes
# ============================
1 192.168.10.220 1
2 192.168.10.78  1
3 192.168.10.84  1
Now by rebooting the different machines with the newly installed kernel you will get one step closer to having a working cluster.

Most RedHat installations have one extra thing to fix. You often get the following error:

[root@inspon root]# /etc/init.d/openmosix start 
Initializing openMosix...
setpe: the supplied table is well-formatted,
but my IP address (127.0.0.1) is not there!
This means that your hostname is not listed in /etc/hosts with the same ip as in your openmosix.map. You might have a machine called omosix1.localhost.org in your hostfile listed as
127.0.0.1      omosix1.localhost.org localhost 
If you modify your /etc/hosts to look like below, openMosix will have less troubles starting up.
192.168.10.78   omosix1.localhost.org
127.0.0.1       localhost 
[root@inspon root]# /etc/init.d/openmosix start 
Initializing openMosix...
[root@inspon root]# /etc/init.d/openmosix status
This is openMosix node #2
Network protocol: 2 (AF_INET)
openMosix range     1-1     begins at 192.168.10.220
openMosix range     2-2     begins at inspon.localhost.be
openMosix range     3-3     begins at 192.168.10.84
Total configured: 3

If you would like to use more bleeding edge patches, you can always opt for the src rpm and run rpmbuild --rebuild on it. This will install the source for you and create an initial config file. From there you can go further applying patches to openMosix

A tutorial on how to build your own openMosix RPM's can be found in the Appendixes.

As new RedHat versions come out, they might be supported out of the box so, feel free to drop the author a note and help him keeping this information updated.