How to force GPT partitions in kickstart for Oracle Linux 6

Question

I want to configure OL6 kickstart to install a system that boots from BIOS but uses GPT partitioning instead of MBR, even for disks <2TB.

The relevant part of my kickstart file looks like this ($ROOTDRIVE has been correctly initialized):

%pre
parted -s $ROOTDRIVE mklabel gpt

bootloader --location=partition --append="elevator=deadline nomodeset inst.gpt" --driveorder=$ROOTDRIVE
part biosboot --fstype biosboot --size=1 --ondisk=$ROOTDRIVE
part /boot --fstype ext3 --size=500 --ondisk=$ROOTDRIVE
part pv.2 --size=1 --grow --ondisk=$ROOTDRIVE`

I have removed clearpart --all --drives=$ROOTDRIVE and zerombr as these supposedly wipe my parted GPT and reinstate MBR.

I believe the following in my conf should result in GPT:

• parted mklabel gpt
• --location=partition (not sure if I really need this?)
• inst.gpt (may be available in OL7 only?)
• part biosboot

Yet my resulting system still lists the primary drive as MBR (msdos label):

[root@localhost ~]$ parted -l
Model: VMware Virtual disk (scsi)
Disk /dev/sda: 172GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

My question: is there any kickstart config I can use to ensure I end up with GPT disks rather than MBR?

Answer 1

Newer versions of kickstart have a --disklabel flag for the clearpart option that can be set to gpt. It appears this was added in Fedora21/RHEL7 so I am not sure if it is available in OL6.

There is an older flag to clearpart, --initlabel, that mentions it "initializes the disk label to the default for your architecture" and would use gpt for Itanium architecture.

If no usable options exist in your version of kickstart, you can configure the disks in the kickstart preinstall script. You could use parted scripting, or whatever tool you use to configure your disks/RAID.