If you have any troubles during the boot process of your install clients and they can't mount the nfsroot, you like to have a shell for debuging.
You can get a shell by adding break=bottom as kernel parameter (in a pxelinux.cfg file). This stops the boot process and spaws a shell within the initramfs. Other values for break= can be found if you search all initramfs scripts for the subroutine maybe_break: maybe_break top maybe_break modules maybe_break premount maybe_break mount maybe_break mountroot maybe_break bottom maybe_break init maybe_break live-premount maybe_break live-bottom maybe_break pre-mdadm maybe_break post-mdadm -- regards Thomas