Re: [SSI-users] adding nodes

[John B. <joh...@hp...>]

Ron Croonenberg wrote:
> Hello,
> 
> I have some additional questions.
> 
> When I start adding nodes using etherboot, does the node that I add have to be
> the same/similar as the masternode ?
> 
> I'm wondering that when I create a boot-image that is going to be used for the
> slave-nodes to netboot from if that can be used to netboot a slave with at all
> if the master node and the slave node are not the same machine.
> 
> any suggestions ?
> 
> thanks,
> 
> Ron

It is possible to use have dissimilar machines, but we are not well set 
up to handle it.

What you have to do depends on exactly what the differences are. For 
instance, with a shared SCSI environment you need to specify different 
modules options on each node, so you need a different modules.conf to 
make the initrd. You can hack /sbin/mkinitrd to be able to use a 
different modules.conf file. You do this by replacing the 
"modulefile=/etc/modules.conf" with 
"modulefile=${modulefile:-/etc/modules.conf"; then you can run mkinitrd 
like "modulefile=/etc/modules.conf.dep mkinitrd ..." to generate a 
mkinitrd for the dependent nodes.

If you need different NIC drivers, then you don't have to deal with the 
modules.conf, you just need to build another initrd with the NIC drivers 
for the dependent node.

For the etherboot image, you will have to run mknbi by hand and place it 
in the /tftpboot directory. (Look in /sbin/cluster_lilo for how to do 
so.) If you had several dissimilar machines then you would have to 
generate images for each machine and modify you /etc/dhcpd.conf to 
specify the different files for each machine. (Which is tricky because 
it gets rebuilt automatically. You probably need to comment the lines 
out for the other nodes in /etc/clustertab and out the stanzas for your 
custom nodes in /etc/dhcpd.proto.)

Better support for situations like this is on our "todo" list, but it is 
kind of far down since we are aiming for larger clusters of similar 
machines. Volunteers to do the script modifications would be welcome. :)

John