How to Boot the openSUSE 16.0 network install image with PXE:

1. Download the CD image available here: get.opensuse.org/leap/16.0/
   I am using this image file: Leap-16.0-online-installer-x86_64.install.iso.
   
   The other files I reference are here: bootimage


2. Mount the image ( as /mnt/cd-16.0)
   mkdir /mnt/cd-16.0
   mount Leap-16.0-online-installer-x86_64.install.iso /mnt/cd-16.0
   
   You can find the linux and initrd files you need to boot it under:
   /mnt/cd-16.0/boot/x86_64/loader/
   Copy those to your tftp boot server.


3. Mount the squashfs.img (in the cd image):
   mkdir /mnt/squashfs-16.0
   mount /mnt/cd-16.0/LiveOS/squashfs.img /mnt/squashfs-16.0


4. Mount the rootfs.img (in the squashfs image):
   mkdir /mnt/rootfs-16.0
   mount /mnt/squashfs-16.0/LiveOS/rootfs.img /mnt/rootfs-16.0


5. Copy the contents of /mnt/rootfs-16.0/ to your nfs server share, I use the folder /export/boot/net-install-opensuse-16.0/READONLY
   (but it could be something else - last directory must be /READONLY, or the below will be very hard to follow):
   mkdir -p /export/boot/net-install-opensuse-16.0/READONLY
   cp -a /mnt/rootfs-16.0/. /export/boot/net-install-opensuse-16.0/READONLY/.


6. Move these folders from READONLY up:
   cd /export/boot/net-install-opensuse-16.0
   mv -i READONLY/dev .
   mv -i READONLY/mnt .
   mv -i READONLY/proc .
   mv -i READONLY/run .
   mv -i READONLY/sys .
   mv -i READONLY/tmp .


7. Make links in READONLY for the moved folders:
   cd /export/boot/net-install-opensuse-16.0/READONLY
   ln -si ../* .
   (DO NOT replace existing folders).
   rm READONLY OVERLAY
   (This is to make sure links in the subfolders of READONLY/ work).


8. In /export/boot/net-install-opensuse-16.0/, create the folder OVERLAY/:
   mkdir /export/boot/net-install-opensuse-16.0/OVERLAY
   
   And make links in OVERLAY for folders (and the one file) in READONLY/:
   cd /export/boot/net-install-opensuse-16.0/OVERLAY
   ln -s ../READONLY/.profile .
   ln -s ../READONLY/* .


9. Make links in the main folder for folders (and the one file) in OVERLAY/:
   cd /export/boot/net-install-opensuse-16.0
   ln -s OVERLAY/.profile .
   ln -si OVERLAY/* .
   (DO NOT replace existing folders).


10. Now place the files I have shared here: bootimage/usr/local/sbin/
    in: /export/boot/net-install-opensuse-16.0/READONLY/usr/local/sbin/


11. Export "/export/boot" with the options: -ro,sec=sys,no_root_squash,subtree_check,async
    ( You could just export "/export/boot/net-install-opensuse-16.0" )


12. Use this file as a template for your boot loader: bootimage/grub-boot.cfg
    It NFS mounts /export/boot/net-install-opensuse-16.0/ as root ( nfsroot=repo-suse-start.localdomain:/export/boot/net-install-opensuse-16.0,ro )
    And starts (as init) the special init.sh you put in place ( init=/usr/local/sbin/init.sh ).