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Chapter 30. Configuring ELILO
ELILO is the boot loader used on EFI-based systems, notably Itanium®. Similar to the GRUB, the boot loader on x86 and x86-64 systems, ELILO allows the user to select which installed kernel to load during the system boot sequence. ELILO also allows the user to pass arguments to the kernel. The ELILO configuration file, which is located in the EFI boot partition and symbolically linked to
/etc/elilo.conf, contains a list of global options and image stanzas. When you install the
kernel-xenRPM, a post install script adds the appropriate image stanza to the
This section on ELILO is for systems running the Xen kernel on the Intel Itanium architecture.
The ELILO configuration file has two sections:
- Global options that affect the behavior of ELILO and all the entries. Typically there is no need to change these from the default values.
- Image stanzas that define a boot selection along with associated options.
Here is a sample image stanza in elilo.conf:
image=vmlinuz-2.6.18-92.el5xen vmm=xen.gz-2.6.18-92.el5 label=linux initrd=initrd-2.6.18-92.el5xen.img read-only root=/dev/VolGroup00/rhel5_2 append="-- rhgb quiet"
imageparameter indicates the following lines apply to a single boot selection. This stanza defines a hypervisor (
initrd, and command line arguments (
append) to the hypervisor and kernel. When ELILO is loaded during the boot sequence, the image is labeled
read-onlyto the kernel command line option
rowhich causes the root file system to be mounted read-only until the
initscriptsmount the root drive as read-write. ELILO copies the "
root" line to the kernel command line. These are merged with the "
append" line to build a complete command line:
"-- root=/dev/VolGroup00/rhel5_2 ro rhgb quiet"
--symbols delimit hypervisor and kernel arguments. The hypervisor arguments come first, then the
--delimiter, followed by the kernel arguments. The hypervisor does not usually have any arguments.
ELILO passes the entire command line to the hypervisor. The hypervisor divides the content and passes the kernel options to the kernel.
To customize the hypervisor, insert parameters before the
--. An example of the hypervisor memory (
mem) parameter and the
quietparameter for the kernel:
append="dom0_mem=2G -- quiet"
ELILO hypervisor parameters
|Set the parameters for the second serial line. Refer the description of the |
A modified example of the configuration above, showing syntax for appending memory and cpu allocation parameters to the hypervisor:
image=vmlinuz-2.6.18-92.el5xen vmm=xen.gz-2.6.18-92.el5 label=linux initrd=initrd-2.6.18-92.el5xen.img read-only root=/dev/VolGroup00/rhel5_2 append="dom0_mem=2G dom0_max_vcpus=2 --"
Additionally this example removes the kernel parameters "
rhgb quiet" so that kernel and
initscriptoutput are generated on the console. Note the double-dash remains so that the append line is correctly interpreted as hypervisor arguments.