Some notes on node image deployment

Nodes are provided in ISO format.  These ISO images can be deployed by either:
1. Writing the image to a CD
2. Writing the image to USB flash using livecd-iso-to-disk utility
3. Creating pxe bootable files using livecd-iso-to-pxeboot utility

To burn a Node image to a usb stick accessible as /dev/sdb:
livecd-iso-to-disk --format /usr/share/ovirt-node-image/ovirt-node-image.iso /dev/sdb

To create vmlinuz and initrd images suitable for pxe booting:
livecd-iso-to-pxeboot /usr/share/ovirt-node-image/ovirt-node-image.iso

The output of livecd-iso-to-pxeboot is a directory called tftpboot that has the
following files in it:
./pxelinux.0
./pxelinux.cfg/default
./vmlinuz0
./initrd0.img

The vmlinuz0/initrd0.img files can be imported into a cobbler server or any
other PXE/tftp server.  pxelinux.cfg/default provides a template for
configuring the pxe server to export the Node image:

DEFAULT pxeboot
TIMEOUT 20
PROMPT 0
LABEL pxeboot
      KERNEL vmlinuz0
      APPEND rootflags=loop initrd=initrd0.img root=/ovirt-node-image.iso rootfstype=auto ro liveimg check rootfstype=iso9660 elevator=deadline
ONERROR LOCALBOOT 0

In addition, PXE booted Nodes rely on the PXE server passing the mac address
of the pxe interface to the kernel.  This is provided by using the IPAPPEND 2
parameter as follows:

DEFAULT pxeboot
TIMEOUT 20
PROMPT 0
LABEL pxeboot
      KERNEL vmlinuz0
      IPAPPEND 2
      APPEND rootflags=loop initrd=initrd0.img root=/ovirt-node-image.iso rootfstype=auto ro liveimg check rootfstype=iso9660 elevator=deadline
ONERROR LOCALBOOT 0