Docs/Howto/Kerrighed
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[edit] Kerrighed
Kerrighed is a Single System Image operating system based on the Linux kernel. http://www.kerrighed.org/
[edit] Kerrighed on Mandriva
Kerrighed is available in Mandriva Cooker. There are also backports for Mandriva 2007.1.
Packages for cooker are available on every cooker mirrors. Backport packages for Mandriva 2007.1 are available at this address : http://people.mandriva.com/~nvigier/kerrighed-2.1.1/2007.1/
[edit] Kerrighed Status
Please be aware that Kerrighed 2.1.1 is still experimental, and does not work on x86_64 yet (only x86), and that it does not support SMP yet. See this page for the roadmap.
[edit] Installation
Kerrighed consists of a patched Kernel, a kernel module, and some userland tools. All you have to do, is install the kerrighed package using urpmi on every nodes of your cluster. If you're using cooker repository :
urpmi kerrighed
Or if you're installing on 2007.1 packages you downloaded manually :
rpm -i kerrighed-2.1.1-1mdv2007.1.i586.rpm kerrighed-kernel-2.1.1-1mdv2007.1.i586.rpm kerrighed-utils-2.1.1-1mdv2007.1.i586.rpm \
libkerrighed-2.1.1-1mdv2007.1.i586.rpm kernel-kerrighed-2.6.20.16-krg2.1.1-2mdv-1-1mdv2007.1.i586.rpm
This should start the installation of the kerrighed kernel, the kerrighed kernel module as well as the kerrighed tools.
[edit] Using Kerrighed
First edit the file /boot/grub/menu.lst. Go to the section for the kerrighed kernel (this should be the one called linux). You should have a line that looks like this :
kernel (hd0,0)/boot/vmlinuz BOOT_IMAGE=linux root=/dev/sda1 acpi=ht resume=/dev/sda5 splash=silent vga=788
replace it with something like this :
kernel (hd0,0)/boot/vmlinuz BOOT_IMAGE=linux root=/dev/sda1 acpi=ht resume=/dev/sda5 vga=788 node_id=0
ie. remove the "splash=silent" option, and add the node_id option. The node_id is the identifier of your node in the cluster, you should give a different number to each node.
Edit the file /etc/kerrighed_nodes to have something like this :
session=1 nbmin=2 12.12.12.1:0:eth0 12.12.12.2:1:eth
See the manpage for details about this file.
Now you can reboot every nodes. Once they are back, load the kerrighed module :
modprobe kerrighed
now you can look at kernel messages using dmesg to check that the correct node_id has been assigned to your node. You should have something like this :
Init Kerrighed low-level framework (nodeid 1) : done
If everything is ok, you can run this command :
krgadm cluster start
If you want the module to be loaded automatically at boot time, you can add the module name (kerrighed) to /etc/modprobe.preload.
Now, if everything is ok, you can run top, and see the process of other nodes. And if you press '1' inside top, you should see more than one CPU.
[edit] Same Root Filesystem
Currently, Kerrighed needs to have exactly the same binaries, libraries and users/groups on every node. To do that, be sure to install the same packages and updates on every node. You can also use replication to replicate one node on the others. An other way to do it is to install Mandriva inside a chroot and use nfsroot on the nodes.
If you're not using nfsroot, you still need to have a common shared filesystem accessible by all the nodes with the same path, for the processes reading and writting files that will be migrated. If a process with files opened on a local filesystem is migrated, weird things could happen.
[edit] Getting more infos
You can get more informations about kerrighed on http://www.kerrighed.org/
