Specifications

Configuring GRUB
GNU Grand Unified Boot Loader (or GRUB) is a program which enables the user to select
which installed operating system or kernel to load at system boot time. It also allows the user to
pass arguments to the kernel. The GRUB configuration file (located in /boot/grub/grub.conf)
is used to create a list of operating systems to boot in GRUB's menu interface. When you install
the kernel-xen RPM, a post script adds kernel-xen entries to the GRUB configuration file. You
can edit the grub.conf file and enable the following GRUB parameter:
title Red Hat Enterprise Linux Server (2.6.18-3.el5xen)
root (hd0; 0)
kernel /xen.gz.-2.6.18-3.el5
module /vmlinuz-2.6..18-3.el5xen ro root=/dev/VolGroup00/LogVol00 rhgb
quiet
module /initrd-2.6.18-3. el5xenxen.img
If you set your Linux grub entries to reflect this example, the boot loader loads the hypervisor,
initrd image, and Linux kernel. Since the kernel entry is on top of the other entries, the kernel
loads into memory first. The boot loader sends (and recieves) command line arguments to and
from the hypervisor and Linux kernel. This example entry shows how you would restrict the
Domain0 linux kernel memory to 800 MB:
title Red Hat Enterprise Linux Server (2.6.18-3.el5xen)
root (hd0; 0)
kernel /xen.gz.-2.6.18-3.el5 dom0_mem=800M
module /vmlinuz-2.6..18-3.el5xen ro root=/dev/VolGroup00/LogVol00 rhgb
quiet
module /initrd-2.6.18-3. el5xenxen.img
You can use these GRUB parameters to configure the Virtualization hypervisor:
mem
This limits the amount of memory that is available for domain0.
com1=115200, 8n1
This enables the first serial port in the system to act as serial console (com2 is assigned for the
next port, and so on...).
Chapter 6.
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