Linux – Access single user mode from the ubuntu live cd boot menu

I agree with the sentiment of the other answers here: Although it may be possible to install Ubuntu remotely on RHEL 3.4, you are likely going to be treading on some very thin ice.

I think the biggest problem you may have is the age of the kernel and libc on the existing system. Is that a 2.4.x-series kernel? If so, I'm not sure you'll be able to pull this off, because at some point during your install, you'll need to run tools that were compiled to run in Ubuntu's kernel and libc, and they may not function properly (or at all) on an older runtime environment. If you are not running a 2.6.x-series kernel on the remote server, I don't think you have much chance of success.

If you still think you might want to try this, there are a couple of guides I am aware of:

• Installing new Debian systems with debootstrap, on debian-administration.org. Although it is Debian-specific, it is mostly applicable to Ubuntu as well.

• Installing Debian GNU/Linux from a Unix/Linux System, from the Debian GNU/Linux Installation Guide. Again, Debian-specific, but mostly applicable.

Both of those guides are kind of old, so neither can be treated as anything even close to a cut-and-paste guide. I would strongly suggest following the advice of others here and do some dry runs on a local server or a VM, because there are definitely kinks and gotchas you'll need to work out before going ahead for real.

Your going to have to add this flag to the pxe boot config "device_mapper_multipath=yes" for example:

default xenserver
label xenserver
       kernel mboot.c32
       append /tftpboot/xenserver/xen.gz dom0_mem=752M com1=115200,8n1 \
       console=com1,vga --- /tftpboot/xenserver/vmlinuz \
       xencons=hvc console=hvc0 console=tty0 \ 
       device_mapper_multipath=yes \
       --- /tftpboot/xenserver/install.img

KDB Article here :

http://docs.vmd.citrix.com/XenServer/5.6.0fp1/1.0/en_gb/installation.html#boot_from_san