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Last updated on 2008-01-11.
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You want a distribution CD containing the latest distribution with all current updates, and only your selection, on to one single disk.
Mostly the information bellow is hacked from "Burning a RedHat CD HOWTO" http://imsb.au.dk/~mok/linux/doc/RedHat-CD.html
The toplevel directory for RedHat Linux release contains distributions for the different platforms, and a directory containing updates and corrections to program packages that have been published since the release.
The images directory contains boot floppy images that must be copied to a diskette. The boot image is called boot.img, which is required when installation is performed directly from a CD-ROM. If installation from a local hard disk, NFS mounted disk or FTP is required, the supplementary disk image supp.img might be needed.
The misc directory contains source and executables of a number of programs needed for the installation. Finally, the iso directory contains iso9660 images just like the one you we about to make.
The most important part of the directory tree is rooted in the RedHat directory: drwxr-xr-x 2 root root 28672 Oct 26 09:01 RPMS drwxr-xr-x 2 root root 4096 Oct 26 09:01 base -rw-r—r-- 1 root root 0 Jan 19 1999 i386 drwxr-xr-x 6 root root 4096 Oct 26 09:01 instimage
The RPMS directory contains the major part of the Red Hat distribution consisting of a set of RPM (Redhat Package Manager) files. An RPM package typically contains binary executables, along with relevant configuration files and documentation. See the section RPM packages for more information.
The base directory holds different book-keeping files needed during the installation process, e.g. the comps file, which defines the components (groups of packages) used during the "Choose packages to install" phase. See section The comps file for more information on this file, and how to use it. Another important file in the base directory is the hdlist file containing most of the header fields from all the RPMs in the RPMS directory.
This means that all the interdependencies among RPM packages can be determined just by reading hdlist without having to read all the RPM packages which is quite convenient especially during FTP installs.
Another use of hdlist is mapping package names to file name, eg. perl to perl-5.004-6.i386.rpm. This means that if you want to incorporate updates from RedHat (see section Incorporating the updates) or add your own packages to the RPMS directory, you need to update hdlist. This is descriped later in Generating a new hdlist file.
The instimage directory contains a bare-bones live file system with a number of programs and shared libraries needed during the installation procedure.
If you maintain a mirror of the updates directory, you can at any time produce a CD including the current updates by repeating these steps.
During the installation process, some programs are run directly off the CD. Unfortunately, the FTP program does not always preserve the protection modes of the files and directories that are copied. Therefore, it is necessary to make sure that execute permission is given to programs, shell scripts and shared libraries, before the directory is burned on the CD. This is done by running the updatePerm script on your local copy of the distribution:
Joshua Sarro <mthed@shore.net> has contributed a perl script called updateMirror.pl that copies all files from the update directory to the RPMS directory. The script uses some nifty rpm tricks to determine what packages in directory. The "kernel" packages that come in several flavors are also preserved (Certain RPMs, specifically the kernel and kernel-smp packages, include the platform in the filename but not in the package name). You can fetch it here: http://imsb.au.dk/~mok/linux/doc/updateMirror.pl.
When installing from the CD, the installation program on the CD relies on the file RedHat/base/hdlist describing what RPM packages are available on the CD. The hdlist file can be generated by the program misc/src/install/genhdlist. This program must be run with the absolute path to the root of the distribution as the only argument. Here is the updateHdlist script which calls that program:
#!/bin/bash
RHVERSION=6.1 ARCH=i386
echo generating hdlist...
RHROOT=/jaz/redhat-${RHVERSION}
GENHDDIR=${RHROOT}/${ARCH}/misc/src/install
GENHDDIR=${RHROOT}/${ARCH}/misc/src/anaconda/utilschmod u+x ${GENHDDIR}/genhdlist
chmod 644 ${RHROOT}/${ARCH}/RedHat/base/hdlist
${GENHDDIR}/genhdlist ${RHROOT}/${ARCH} || echo "** GENHDLIST FAILED **"exit 0
The installation in RedHat 6.1 is completely changed from earlier versions, and RedHat have introduced a system called “anaconda”. The genhdlist program is now found in a different place, so in the script has changed in GENHDDIR.
The comps file defines how the packages are bundled during the installation. In the Red Hat distribution, this is done according to the functionality they provide, for example:
Printer Support X Window System GNOME KDE Mail/WWW/News Tools ... Kernel Development Extra Documentation
Sometime during the installation process, the user is presented with a dialog called "Components to install". Some of the components have been preselected, and others not.
On the dialog box, there also is an option that enables the user to customize exactly what packages will be installed. Customizing the installation by hand, or selecting "Everything" in the components list is the only way to have your own packages installed unless you modify the RedHat/base/comps file.
With RedHat version 6.1, we have not yet disected it to discover the file format. With the bellow information, however, it should be easy enough to do it yourself. The decoding takes place in
${RHROOT}/${ARCH}/misc/src/anaconda/comps.py.The format of the comps file currently starts with a header describing the version of the comps format, followed by an empty line.
0.1 <empty line>
After this, the components are listed, separated by empty lines:
<component 1> <empty line> <component 2> <empty line> . . <component n> <empty line> EOF
Each component has the following definition:
(0|1) (--hide)? <name> <RPM 1> <RPM 2> ... <RPM n> end
Before the name of each component, 0 or 1 is given. A value of 1 here means that the component is chosen by default, and 0 means it's not. The option "—hide" means that you will not see the entry, unless you choose "expert" installation. The first component is called "Base", and that is special, in the sense that it must be present and it does not show up in the dialog (you can't deselect the base installation, which makes sense…)
Next follows a list of rpm packages belonging to that component. Note that this is the package name stored in the rpm file, and not any part of the file name of the package (although it is often the same).
By adding your packages to the comps file, you can customize your own distribution, and make sure that your packages will be installed by default. One thing to be careful about is interdependence among your packages, but here, you are on your own :-) A word of warning: be careful not to add or remove extra whitespace in the file. Examine the existing comps file (make a copy of the original) to see how it's done (or check i386/misc/src/install/pkgs.c if you want to see how the file is parsed).
Make sure the top directory of the CD contains at least the following files and directories:
COPYING RPM-PGP-KEY README RedHat/
The following directories might come in handy:
doc/ gnome/ misc/ dosutils/ images/
If you're paranoid you can test your new disk image by mounting it. If you forgot to fix the file permissions or set the rock ridge extensions then the error will be obvious here since the file names and directory structure will be wrong.
mount -t iso9660 -o ro,loop=/dev/loop0 /tmp/redhat.img /mnt/cdrom
When you're done, don't forget to unmount it.
umount /mnt/cdrom
This perl script to extract a list of rpms from the /RedHat/RPMS directory on the cdrom. I only had about 6 corrections to make and figured it would take me longer to fix the perl script that it would be to fix the list.
#!/usr/bin/perl
while(my $Rpm = <>){
if ($Rpm =~ /\-[0-9]+\-[0-9]+\./)
{($Rpm,$Junk) = split(/\-[0-9]+\-[0-9]\./, $Rpm,2);}
elsif ($Rpm =~ /\-[0-9]+\./)
{($Rpm,$Junk) = split(/\-[0-9]+\./, $Rpm,2);}
else {($Rpm,$Junk) = split(/\-[0-9]/, $Rpm,2);}
print $Rpm\n";
}