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Configuring Serial Console with OpenSSI

You should already be familiar with configuring a serial console before 
reading this document. If you're not, the following HOWTO can be
helpful:

http://www.tldp.org/HOWTO/Remote-Serial-Console-HOWTO/

The only extra thing to be aware of with an OpenSSI cluster is that a 
booting node gets its kernel arguments from one of three places, depending
on how it boots:

1) Nodes with local boot devices get their kernel arguments from their 
local copy of /etc/grub.conf. Whenever you update this file, you should run 
ssi-ksync to push your changes to all local boot devices.

2) Nodes that PXE boot get their kernel arguments from 
/tftpboot/pxelinux.cfg/default. This file is read everytime a node PXE boots.

A sample change would be:

 label openssi
 kernel kernel
-append initrd=initrd ro panic=15
+append initrd=initrd ro console=tty0 console=ttyS0,115200 panic=15

3) Nodes that Etherboot get their kernel arguments from the 
/tftpboot/combined image, which contains the kernel, kernel arguments and 
initrd for an etherbooting node. To modify the kernel arguments, edit the
--append option to the mkelf-linux command at the bottom of the 
/sbin/ssi-ksync-network script. After you change these arguments, be 
sure to run either ssi-ksync or ssi-ksync-network to generate a new 
/tftpboot/combined image. You will probably need to `touch' the kernel or
initrd before running the script, so that it will know it needs to rebuild 
the image.

A sample change would be:

 if [ $RUN_MKELF -eq 1 ]; then
-	mkelf-linux --append='panic=15' \
+	mkelf-linux --append='console=tty0 console=ttyS0,115200 panic=15' \
 		$kernel $initrd >/tftpboot/combined
 fi

4) As suggested in the HOWTO referenced above, you probably added a line to
your /etc/inittab to run a getty program on the serial console (otherwise
you could not login from the serial console). You should add a 'U' to the 
runlevel information for this line, so that this getty is started on all
nodes in the cluster, and not just the init node.

For example:

co:2345U:respawn:/sbin/agetty ttyS0 9600

This page last updated on Thu Dec 15 17:17:43 2005 GMT
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