netboot tarball needs a symlink to facilitate multi-arch installation

[Simon Kelley]

Binary package hint: debian-installer

The netboot.tar.gz tarball has symlinks at the top level from pxelinux.0 to
ubuntu-installer/$ARCH/pxelinux.0 and pxelinux.cfg to ubuntu-installer/$ARCH/pxelinux.cfg
This causes a problem is more than one arch netboot is installed, or if
the Debian netboot tarball is installed, since the symlinks trample on
each other.

The simplest way to avoid this when setting up a multi-arch/distro boot
server is to ignore the top-level symlinks, and set the bootfile name
in the DHCP/PXE config to include the directory, so instead of using a
filename pxelinux.0, use the filename ubuntu-installer/$ARCH/pxelinux.0
PXE ROMs are bright enough to spot and use the prefixed directory, so
they continue to download files from there; pxelinux.cfg is found, no
problem.

The problem occurs with all of the boot screens, etc, whose paths inside
pxelinux.cfg already include the ubuntu-installer/$ARCH/ prefix. The PXE
ROM adds the path again, and tries to tftp eg.
ubuntu-installer/$ARCH/ubuntu-installer/$ARCH/boot-screens/splash.png

The simplest way to fix this, is to add a symlink in the netboot tarball
from ubuntu-installer/$ARCH/ubuntu-installer to ../../ubuntu-installer.
This is completely backwards compatible, it doesn't affect the majority
who continue to rely on the top-level symlinks and a simple DHCP
filenname config, but it does allow more complex configurations to work
without manually making the link.

ProblemType: Bug
Architecture: i386
Dependencies:

DistroRelease: Ubuntu 9.04
Package: debian-installer None [modified: /var/lib/dpkg/info/debian-installer.list]
ProcEnviron:
 LANG=en_GB.UTF-8
 SHELL=/bin/bash
SourcePackage: debian-installer
Tags: ubuntu-unr
Uname: Linux 2.6.28-11-generic i686
UnreportableReason: This is not a genuine Ubuntu package