As part of T78135: Provide a pxe-bootable rescue image and to make things simple we should be providing a choice menu via pxelinux (https://www.syslinux.org/wiki/index.php?title=Menu) to select actions besides "run d-i" at pxeboot time.
The first and default option is going to be d-i to leave current behavior unchanged for the time being.
- d-i (default)
- rescue
- boot from disk
Other options can include burning, wipe disks, etc