PXE boot always boots hd0 regardless of which drive is selected as the boot drive.

PXE boot always boots hd0 regardless of which drive is selected as the boot drive. This is a problem for some devices that refuse to order drives properly (HPE sl230s servers booting from internal flash storage, for example).

config.local.i386.template forces boot from hd0:

> https://github.com/maas/maas/blob/2.3/src/provisioningserver/templates/pxe/config.local.i386.template

> DEFAULT local
>
> LABEL local
> SAY Booting local disk ...
> KERNEL chain.c32
> APPEND hd0

chain.c32 supports booting disk/partition by lable, guid, or MBR serial:

http://www.syslinux.org/wiki/index.php?title=Comboot/chain.c32

> chain.c32 hd<disk#> [<partition>] [options]
> chain.c32 fd<disk#> [options]
> chain.c32 mbr:<id> [<partition>] [options]
> chain.c32 boot [<partition>] [options]
> chain.c32 fs [options]
> chain.c32 label=<label> [options]
> chain.c32 guid=<label> [options]
>
> ...
>
> Find partition by uuid or label in all GPT partitions on all available drives:
> label=mylabel
> guid=myguid
> Note that label and guid work only on GPT partition tables; it is not filesystem but partition label and guid.
>
> ...
>
> mbr
>
> The mbr: syntax means search all the hard disks until one with a specific MBR serial number (bytes 440-443) is found.
> You can get the MBR serial number, by running the following command (change /dev/sda to the correct device):
> $ hexdump -s 440 -n 4 -e '"0x%08x\n"' /dev/sda
> 0x0ec8694c
> Or by running:
> $ fdisk -l /dev/sda
> ...
> Disk identifier: 0x0ec8694c
> Example:
> LABEL mbr_serial
> COM32 chain.c32
> APPEND mbr:0x0ec8694c

MAAS could note the disk/partition guid or MBR serial on deployment and tell chain.c32 to boot that disk in order to ensure that the disk with grub installed is the disk that gets booted.