The default parameters for the GRUB bootloader is the master boot record on the first BIOS-enabled drive. However, sometimes more control is needed to support alternative configurations or to work around either anaconda (the installer) issues or platform BIOS problems. For Rocks version 6, the default parameters are
These are encoded into the base.xml configuration node and is part of the base roll.
It is possible to completely override the default with the Bootloader attribute. This affects the generation of the node's kickstart file. The most common change is the --driveorder option to tell anaconda precisely which device is the first in the BIOS boot order. In the following example, we set the driveorder to "sda" for node compute-0-0.
# rocks set host attr compute-0-0 Bootloader value="--location=mbr --timeout=5 --driveorder=sda"
One can check the value as follows
# rocks list host attr compute-0-0 | grep Bootloader compute-0-0: Bootloader --location=mbr --timeout=5 --driveorder=sda H
We see that compute-0-0 has the Bootloader attribute set. The "H" indicates that this attribute is a Host-specific attribute.
If you define a Bootloader attribute, you must include the --location= directive. This is an Anaconda requirement
The full set of bootloader options is available at Kickstart Options
To revert to the Rocks default, one simply removes the attribute
# rocks remove host attr compute-0-0 attr=Bootloader