dhcp vendor-option and grub net_pxe_extensionspath

[Carl Karsten]

I am using dnsmasq, but I can bring up isc dhcp too.  I need help with both
sides, but on the grub list I won't be too picky about what dhcp server is
used.

I am looking for the syntax of dhcp vendor options, and then how to access
them in grub-net.  I think.  maybe there is a better way.

I pxe boot grub, which boots di (Debian Installer) and pass a preseed file.

I am trying to work out a nice way to pass host specific info to di
example, most use:
partman-auto/disk="/dev/sda"
but one machine has an onboard ssd nvme which needs /dev/nvme0n1

di will read values appended to the kernel boot line, so I can hard code it
like this:

menuentry "Install Ubuntu preseed" {
set gfxpayload=keep
linux /ubuntu-installer/amd64/linux gfxpayload=800x600x16,800x600 ---
auto=true url=dc10b hostname= partman-auto/disk="/dev/nvme0n1"
interface=${net_default_mac}
initrd /ubuntu-installer/amd64/initrd.gz
}

interface=${net_default_mac} - use the nic that pxe booted.

Now I get lost in conf options and syntax.  forgive me for making stuff up
here, if it worked I wouldn't be asking for help.

I am hoping for something like
partman-auto/disk=$(net_pxe_extensionspath/disk}

in dnsmasq conf:
dhcp-host=40:8d:5c:7f:bb:90,,gator

dhcp-option-force=host:gator,209,"disk=/dev/nvme0n1"

So yeah, how do I send random strings based on mac/hostname
and how do I read what was sent in grub?

--
Carl K