Use an external PXE (DHCP+TFTP) subsystem for UEFI-based hosts installation

Support
1

We build our BIOS-based hosts by Satellite using an external PXE subsystem (DHCP+TFTP) because we have a multi-use menu system, used also for other reasons.
It uses pxelinux.0 as bootloader and a menu with an entry to chain to Satellite:

LABEL Satellite
        MENU LABEL Satellite
        KERNEL pxechain.com
        APPEND 10.61.0.199::pxelinux.0

Now I’m trying to do same thing for UEFI-based servers, using grub2 (or any other bootloader) but I’m unable to find a method to chain to Satellite. Any help?

2

Just a quick question @Mimmus,

Have you tried this: https://docs.theforeman.org/master/Provisioning_Guide/index-foreman.html#creating-hosts-with-uefi-http-boot-provisioning_provisioning

3

No, @mcorr, it sounds interesting but problem is always that I don’t know how to configure external DHCP+TFTP to have a menu entry to point to Satellite.

Thanks again

4

We don’t ship or test any configuration or workflow utilizing this kind of chainbooting. Just try PXELinux EFI, it’s shipped with Fedora in syslinux-efi64-6.04 package, unfortunately you will not find it in EL7.

5

PXELinux-EFI works but unfortunately no chainloading is supported.

I have to dismiss my menu-based PXE server and point DHCP directly to Satellite every time I need to build a UEFI bare-metal host.

6

I don’t think so.

Grub2 has a powerful shell-like scripting language. You can do quite something with it. How about:

  • grub2 is loaded using PXE/UEFI or HTTP UEFI
  • grub2 loads its configuration
  • one of the entry is customized by you “Load menu from a different server”

Now, you can easily dismiss the current menu and replace it with a new menu from Satellite or any source actually. I am assuming you want to load from Foreman/Satellite Proxy/Capsule.

set root=(tftp,192.168.1.1)
source /grub2/grub.cfg

The first statement sets root variable to the new TFTP server (you can probably even use hostname). The second is similar to bash - load and evaluate a “script”. Once those statements get evaluated, since root is now correct it will perform various other things like trying to load customized MAC based configuration, the template is here:

Alternatively if TFTP is not the option, you can enable HTTPBoot feature on the Proxy/Capsule and then do:

set root=(http,hostname)
source (http,hostname)/httpboot/grub2/grub.cfg

It will do the same but over HTTP, for this you make sure you have grubx64.efi from the latest RHEL 7.9, HTTP had some bugs which we recently fixed.

8

It sounds interesting!
But I have the opposite need: i have a DHCP/TFTP server, with the menu-system and I need an entry to “forward” to Satellite/Capsule default menu.
I was able to boot UEFI using grub2 and to create a menu by grub.cfg config file but I have some troubles to build an entry for Satellite:

menuentry 'Satellite' {
  set root=(tftp,10.61.0.199)
  set prefix=(tftp,10.61.0.199)/grub2
  source /grub2/grub.cfg
}

What other config options do I need to insert?

9

OK, after enabling my operating system in PXEGrub2 template, IT WORKS!

Thank you very much

1 Like