1.1. Disclaimer and License

This document is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Neither the author nor the distributors, or any other contributor of this document are in any way responsible for physical, financial, moral or any other type of damage incurred by following the suggestions in this text.

2.1. Redhat 9 directories organization

The latest distribution is, as of this writing, available only for the i386 platform. The toplevel directory appears a bit shallow, given the presence of a single architecture. (pub/redhat/linux/9/en/os/ ).

i386/

Otherwise, the toplevel directory, for releases slightly older than 9, contains distributions for the different platforms. For example, the corresponding directory for release 7.1 of Redhat Linux, is structured this way:

alpha/ i386/ ia64/ ppc/ s390x/

The root of the i386 directory in a Redhat 9 distribution looks like this:

-rwxr-xr-x 2 root root 248 Mar 14 2003 autorun drwxr-xr-x 7 root root 4096 Mar 14 2003 dosutils -rw-r--r-- 3 root root 6192 Mar 14 2003 EULA -rw-r--r-- 3 root root 18385 Mar 14 2003 GPL drwxr-xr-x 3 root root 2048 Mar 14 2003 images drwxr-xr-x 2 root root 2048 Mar 14 2003 isolinux -rw-r--r-- 3 root root 6127 Mar 14 2003 README -rw-r--r-- 2 root root 13052 Mar 14 2003 README-Accessibility -rw-r--r-- 2 root root 6686 Mar 14 2003 README.de -rw-r--r-- 2 root root 6990 Mar 14 2003 README.es -rw-r--r-- 2 root root 6492 Mar 14 2003 README.fr -rw-r--r-- 2 root root 6805 Mar 14 2003 README.it -rw-r--r-- 2 root root 7995 Mar 14 2003 README.ja -rw-r--r-- 2 root root 7312 Mar 14 2003 README.ko -rw-r--r-- 2 root root 5070 Mar 14 2003 README.pt -rw-r--r-- 2 root root 6613 Mar 14 2003 README.pt_BR -rw-r--r-- 2 root root 5879 Mar 14 2003 README.zh_CN -rw-r--r-- 2 root root 5892 Mar 14 2003 README.zh_TW drwxr-xr-x 4 root root 2048 Mar 14 2003 RedHat -rw-r--r-- 2 root root 25824 Mar 14 2003 RELEASE-NOTES -rw-r--r-- 2 root root 29902 Mar 14 2003 RELEASE-NOTES-de.html -rw-r--r-- 2 root root 30409 Mar 14 2003 RELEASE-NOTES-es.html -rw-r--r-- 2 root root 32354 Mar 14 2003 RELEASE-NOTES-fr.html -rw-r--r-- 2 root root 30064 Mar 14 2003 RELEASE-NOTES.html -rw-r--r-- 2 root root 29925 Mar 14 2003 RELEASE-NOTES-it.html -rw-r--r-- 2 root root 34666 Mar 14 2003 RELEASE-NOTES-ja.html -rw-r--r-- 2 root root 33520 Mar 14 2003 RELEASE-NOTES-ko.html -rw-r--r-- 2 root root 29496 Mar 14 2003 RELEASE-NOTES-pt_BR.html -rw-r--r-- 2 root root 22747 Mar 14 2003 RELEASE-NOTES-pt.html -rw-r--r-- 2 root root 25217 Mar 14 2003 RELEASE-NOTES-zh_CN.html -rw-r--r-- 2 root root 26645 Mar 14 2003 RELEASE-NOTES-zh_TW.html -rw-r--r-- 3 root root 1910 Mar 14 2003 RPM-GPG-KEY -r--r--r-- 1 root root 1823 Mar 14 2003 TRANS.TBL

The SRPMS directory contains the RPMS packages in source form.

The images directory contains boot and drivers floppy images that can be copied to a diskette if needed. In the 9 release, there is only one boot disk image available. This boot image is named bootdisk.img. A secondary driver disk is required beside this one if the installation is not performed directly from a CD-ROM or HD. A boot.iso file has now been added to boot a machine from the cdrom drive and start (network) installations more easily (i.e. without messing up with too many floppies). See section Installation and references therein for details and consult the README file in the directory for a more detailed explanation of the various files.

The isolinux directory contains the files needed to boot from the CD (and to rebuild bootable CDs which work the same way). This process was moved from floppy emulation to no emulation. This helps avoiding space constraints and compatibility problems.

The dosutils directory contains various programs for some other operating systems which are sometimes useful to support the installation process. An explanatory README file is included also in this case.

The listing is completed by a lot of files and the RedHat directory. The latter is the subject of the next sections while the formers have contents which will appear straightforward by simply reading their names (perhaps apart from the EULA, or End User License Agreement).

2.2. The "RedHat" directory -- the core of the distribution

The most important part of the directory tree is rooted in the RedHat directory:

drwxr-xr-x 2 root root 53248 Jun 14 03:15 RPMS drwxr-xr-x 2 root root 4096 Jun 14 04:15 base

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 files needed during the installation process, like the comps.xml 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.

Two other important files in the base directory are hdlist and hdlist2 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 these files without having to read all the RPM packages which is quite convenient especially during FTP installs. Another use of these files is mapping package names to file names (eg. perl to perl-5.004-6.i386.rpm). This means that if you want to incorporate updates from RedHat (see section Including the updates) or add your own packages to the RPMS directory, you need to update hdlist and hdlist2. This is described later in Rebuilding the installer. Besides these files, the images from which the installation environment (i.e. kernel, python interpreter, anaconda, etc.) is loaded are found.

2.3. The "updates" directory

The /pub/redhat/linux/updates directory has updates for all releases of RedHat's distribution since version 3.0.3. This is the place to find software packages that have been updated for some reason or other. You should especially be aware of security updates. These are publicised on RedHat's errata page whenever a fix is available. The most important files found in the updates directory are:

drwxrwsr-x 3 root root 4096 Jul 13 10:13 5.2 drwxrwsr-x 3 root root 4096 Jul 13 10:13 6.0 drwxrwsr-x 3 root root 4096 Jul 13 10:13 6.1 drwxrwsr-x 4 root root 4096 Jul 13 10:14 6.2 drwxrwsr-x 4 root root 4096 Jul 13 10:14 7.0 drwxrwsr-x 4 root root 4096 Jul 13 10:14 7.1 drwxrwsr-x 4 root root 4096 Jul 13 10:13 7.2 drwxrwsr-x 3 root root 4096 Jul 13 10:14 7.3 drwxrwsr-x 3 root root 4096 Jul 13 10:14 8.0 drwxrwsr-x 3 root root 4096 Jul 13 10:14 9

The structure of each of these directories is similar to that described in the section The Redhat 9 tree. So you will find for each version, in the subdirectory en/os/ a series of subdirectories representing the various architectures and a noarch and SRPMS subdirectories, for packages which work on every architecture or are in source form respectively.

drwxrwsr-x 2 root root 4096 Sep 23 05:28 SRPMS drwxrwsr-x 2 root root 4096 Aug 28 18:25 athlon drwxrwsr-x 2 root root 8192 Sep 23 05:28 i386 drwxrwsr-x 2 root root 4096 Jul 13 10:14 i486 drwxrwsr-x 2 root root 4096 Aug 28 18:26 i586 drwxrwsr-x 2 root root 4096 Aug 28 18:26 i686 drwxrwsr-x 2 root root 4096 Jul 13 10:14 noarch

2.4. Differences for the 8.0 tree

The 8.0 distribution layout is almost identical to the one just described. The only major differences, in this respect, can be found in the images directory.

The images directory contains boot and drivers floppy images that can be copied to a diskette if needed. In the 8.0 release, there are three boot disk images available. The first boot image is called boot.img, and is required when installation is performed directly from a CD-ROM. If installing from a NFS mounted disk or FTP is required, the bootnet.img disk image is needed. Installs through PCMCIA adapters need the pcmcia.img floppy. See section Installation and references therein for details and consult the README file in the directory for a more detailed explanation of the various files.

2.5. Differences for the 7.x tree

The two distributions are fairly similar in this respect. The only changes which are of some interest to us (and easy to notice with a simple inspection of the main distribution tree) are represented by a missing isolinux directory and some changes in the RedHat/base directory. The first one is due to the way the installation CDs are made bootable in releases prior to 8.0 ("floppy emulation" has been superseded by "no emulation" in release 8.0), while the second is an effect of the migration of the comps file format to XML in Redhat releases after 8.0 (that's why it was renamed comps.xml). The Redhat/base/comps file is, in fact, a simple textual file with a quite inflexible syntax in releases prior to and including Redhat 7.3.

2.6. Differences for the 6.x tree

For release 6.2 ( pub/redhat/linux/6.2/en/os/), the last of the 6 series, the organization is the following (the previous releases are mostly similar if not really equal, in this respect):

alpha/ i386/ sparc/

While the root of the i386 directory looks like this:

-rw-r--r-- 1 root root 18385 Sep 7 1999 COPYING -rw-r--r-- 1 root root 3400 Mar 8 2000 README -rw-r--r-- 1 root root 16300 Mar 8 2000 RELEASE-NOTES -rw-r--r-- 1 root root 1908 Sep 25 1999 RPM-GPG-KEY drwxr-xr-x 1 root root 512 Sep 27 15:22 RedHat drwxr-xr-x 1 root root 17408 Sep 27 15:22 SRPMS -rwxr-xr-x 1 root root 538 Sep 26 1999 autorun -rwxr--r-- 1 root root 2048 Mar 9 2000 boot.cat drwxr-xr-x 1 root root 512 Sep 27 15:22 doc drwxr-xr-x 1 root root 512 Sep 27 15:22 dosutils drwxr-xr-x 1 root root 512 Sep 27 15:22 images drwxr-xr-x 1 root root 512 Sep 27 15:22 misc

In the following paragraphs I will only list differences from the newest releases, what is not explicitly mentioned is (or is believed to be) unchanged.

The doc directory contains an abundance of information. Most importantly, the RedHat installation manual can be found in HTML format in the directory or on the Redhat website ( Redhat 6.2 Installation guide). Next, there are the reference guide and the getting started guide. The documentation for the 7.x/8.0/9 releases is on a separate CD (in a different tree, on the ftp site).

The images directory contains boot floppy images that can be copied to a diskette if needed, like for 8.0, 7.3 and 9. See section Installation and references therein for details. The misc directory contains source and executables of a number of programs needed for the installation.

The most important part of the directory tree is (again) 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 should be already known to you. See the section RPM packages for more informations. The base directory holds different book-keeping files needed during the installation process, like for releases 7.3, 8.0 and 9. The only noticeable differences being represented by a single hdlist file and a missing stage2.img file whose functionalities should be provided by the files included in the instimage directory. This contains, in fact, a bare-bones live file system with a number of programs and shared libraries needed during the installation procedure.

The updates directory is really similar to the one described for release 9 with the only difference of having more architecture related directories.

3.1. Comparing two versions of a RPM package

The C code included in the three files Makefile, rvc.h, rvc.c was extracted from the Redhat Package Manager and (slightly) modified to fit our needs. They form a simple C program which given two versions A and B of a package returns 1, 0 or -1 if A is respectively newer, equal or older than B and other values in case of error (you can read the code comments for more detailed informations). To compile the program (you need the make program and the gcc C compiler), put the files in the same directory and issue the command:

$ make

This program is needed by almost every script used in the following sections and is found setting the RVC variable in the file rhcd.conf.

You can find a copy of the source and a precompiled version in the archive rhcd-sripts.tar.gz in the rpmvc directory.

There was an error in the way this program was used by the updateDist.sh (ver. < 1.17) and updateCD.sh (ver. < 1.12) scripts. I strongly suggest to avoid versions of the scripts which have lower release numbers than the reported ones, even if the problem doesn't show up really frequently (at least apparently).

4.1. Using wget and bash

This is not the simplest, even if, probably, the most accurate way. I like it because it works comparing the RPM versions of the files and not the dates/times or names (like the standard mirroring packages) and it checks the signatures of the updates each time it downloads some of them if configured to do so by means of the CHECKSIG variable in the rhcd.conf file.

Create a directory to hold the installation files and cd into it, then issue the command (which will download ~3Gb of data on your hard drive):

$ wget -r -c -t0 -l0 --retr-symlinks -nH --cut-dirs=9 \ ftp://ftp.mirror.ac.uk/sites/ftp.redhat.com/pub/redhat/linux/updates/7.3/en/os/i386

You will probably want to change the ftp download mirror and, consequently, the parameter passed to the --cut-dirs option. That's used, in fact, together with -nH to avoid the recreation of the ftp site directory hierarchy. For more information on how to use the option correctly you can have a look at the wget documentation and man page.

If you want to exclude one or more directories from the download, you can use the -X list option, where list represents a comma-separated list of directories. For example to exclude the SRPMS directory from the previous download, you would use:

$ wget -r -c -t0 -l0 --retr-symlinks -nH --cut-dirs=9 \ -X /sites/ftp.redhat.com/pub/redhat/linux/updates/7.3/en/os/i386/SRPMS \ ftp://ftp.mirror.ac.uk/sites/ftp.redhat.com/pub/redhat/linux/updates/7.3/en/os/i386

This could be useful if you consider the size of the SRPMS directory (~1.2GB), or at least, I find it useful.

If you want to check the GPG signatures to make sure of the authenticity of the packages (which is something I suggest) you should install the gnupg package (needed only on Redhat 7.3) and import the security@redhat.com public key you can find in the root directory of the CDs (RPM-GPG-KEY) or on the RedHat website. The key is imported by running the command: gpg --import <filename> in releases up to and including 7.3, which is to be changed to read rpm --import <filename> for releases 8.0 and 9 (for more informations on this have a look at the GNU Privacy Guard and at the RPM - Redhat Package Manager websites).

If you want to check the rpm packages you can do it using the following command (I'm assuming you are issuing it from the directory you have completed the downloads in):

For releases up to and including 7.3:

$ find . -name "*.rpm" -exec rpm -K --nopgp {} \; |grep "NOT *OK"

For release 8.0 and 9 (and for future releases as well I guess):

$ find . -name "*.rpm" -exec rpm -K {} \; |grep "NOT *OK"

If you don't want to "bother" yourself with all these steps, I hope you want to check (at least) for the integrity of the downloaded files (which doesn't mean nobody has tampered with them), verifying the md5 signatures. This is done with:

For releases up to and including 7.3:

$ find . -name "*.rpm" -exec rpm -K --nopgp --nogpg {} \; |grep "NOT *OK"

For release 8.0 and 9 (and for future releases as well, I guess):

$ find . -name "*.rpm" -exec rpm -K --nosignature {} \; |grep "NOT *OK"

The content of a Red Hat distribution does not change between releases, so you only need to download these packages ONCE. All changes to the distribution are in the updates directory. Thus, if you want to keep an up-to-date mirror of the Red Hat distribution, you only need to keep the updates directory current. This is done using the script updateDist.sh. Before using this script you have to configure the rhcd.conf configuration file and export a RHCDPATH variable pointing to the directory where this file is.

$ export RHCDPATH=/home/luigi/tmp/rhcd-scripts $ sh updateDist.sh

The script will download the new updates excluding the subdirectories contained in the EXCLUDELIST variable, moving the old ones (i.e. just superseded by new versions) to the directory represented by the OLDDIR variable after having completed two tests. The first test compares the .listing files generated by wget to the content of the local directories to make sure all the files were downloaded. The second test verifies the packages signatures depending on the values of the two variables CHECKSIG and USEGPG (set both of them to "yes" if you want the operation to be completed). In case of a failure in the signature checking process the script will move the offending packages to OLDDIR assigning them the ".UPDcheckfail" extension and exit without moving the old updates to OLDDIR.

4.2. Using mirror

Mirror is a sophisticated perl script that compares the content of a directory on a remote site with a local directory. It will use FTP to fetch the files that are on the remote site but not the local site, and delete files on the local site that are not on the remote site. The mirror program is configured with a configuration file. The mirror package is available as an RPM from rufus.w3.org. Make your local copy mirror.redhat of the mirror configuration file, and edit the relevant fields at the top of the file. After the default section, define these packages:

package=updates site=ftp.mirror.ac.uk exclude_patt=(SRPMS/) remote_dir=/sites/ftp.redhat.com/pub/redhat/linux/updates/7.3/en/os/i386 local_dir=/home/luigi/tmp/redhat-cd/redhat-7.3-updates package=dist site=ftp.mirror.ac.uk exclude_patt=(SRPMS/) remote_dir=/sites/ftp.redhat.com/pub/redhat/linux/7.3/en/os/i386 local_dir=/home/luigi/tmp/redhat-cd/redhat-7.3

The following command will download a copy of the entire RedHat tree on your local disk. **Think** before you do this, you are about to transfer approximately 1.5Gb of data (if you have excluded the SRPMS directory)!

$ mirror -pdist mirror.redhat

This will mirror the Red Hat FTP site on your local disk. The content of a Red Hat distribution does not change between releases, so you only need to download this package ONCE. All changes to the distribution are in the updates directory. Thus, if you want to keep an up-to-date mirror of the Red Hat distribution, you only need to keep the updates directory current. This is done using the command

$ mirror -pupdates mirror.redhat

You can run this regularly, say, once a week, through a cron script. The RedHat distribution is available on a great number of FTP servers around the world, which are updated daily from the master site at ftp.redhat.com. You should choose an FTP site close to you, see the RedHat list of mirror sites.

I haven't personally tested this procedure. It was the only proposed one for the older versions of the howto (up to version 1.34, regarding RedHat <=6.1).

5.1. Correcting the file protection modes

During the installation process of the releases up to and including 6.2, 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.sh script on your local copy of the distribution. It is really needed only for version 6.2 and older, the only part useful to the 7.3/8.0/9 releases procedure is the directories permissions update, even if the rest won't hurt and things are kept coherent. It is almost equal to the updatePerm script included in the previous version of the howto, just some slight changes were made. Before using this script you have to configure the rhcd.conf configuration file and export a RHCDPATH variable pointing to the directory where this file is.

$ export RHCDPATH=/home/luigi/tmp/rhcd-scripts $ sh updatePerm.sh

5.2. Replacing the updated RPMS

The updateCD.sh script copies all the new files from the update directory to the RPMS (and SRPMS) directory. The script uses the rvc program which was presented in section Comparing RPM versions to determine which packages in the updates directory are more recent. Older packages are moved to the ${OLDDIR} directory. If the CHECKSIG variable is set to "yes", all the packages in the main tree will have their signature checked for correctness. If a package fails the signature check (the kind of check is configured by means of the USEGPG variable whose value is assigned in the file rhcd.conf), it is moved to the OLDDIR directory with an added extension of "CDcheckfail".

Before using this script, you have to configure the rhcd.conf configuration file and export a RHCDPATH variable pointing to the directory where this file is.

$ export RHCDPATH=/home/luigi/tmp/rhcd-scripts $ sh updateCD.sh

After having incorporated the updates in the main RedHat/RPMS directory, your copy of the distribution is no longer a mirror of the Red Hat distribution site. Actually, it is more up-to-date! Therefore, if you attempt to mirror the distribution using mirror, older versions of the RPM's that have been updated will be downloaded once more, and the updates deleted. The bash/wget based procedure doesn't suffer from the problem, but will leave the main tree in an incoherent state. Old and new packages will be in this case mixed together, but you can find and remove them wrapping the rvc binary in a simple shell script (which I will leave as an exercise for the reader...).

5.3. Rebuilding the installer

Things have changed pretty much in this section with the introduction of the anaconda installer (as of release 6.1) and with the considerable increment in size (and ... number of CDs) the 7.x/8.0 distributions have seen. Until release 6.2, the only step composing this section was represented by generating a new hdlist file. With release 6.2, this appears to be true only to a certain extent, because of the changes in the anaconda installer, in the rpm software itself (from version 3.x to 4.x) and the migration of the updated packages to this new version (updates for release 6.2 are in fact packaged with both major releases of the rpm software). We will consider three different procedures trying to cover all the releases.

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5.3.1. RedHat <= 6.1

5.3.1.1. Regenerating the hdlist file

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 (from version 1.34 of this howto):

#!/bin/bash RHVERSION=6.1 ARCH=i386 echo generating hdlist... RHROOT=/home/luigi/tmp/redhat-${RHVERSION} GENHDDIR=${RHROOT}/${ARCH}/misc/src/anaconda/utils chmod u+x ${GENHDDIR}/genhdlist chmod 644 ${RHROOT}/${ARCH}/RedHat/base/hdlist ${GENHDDIR}/genhdlist ${RHROOT}/${ARCH} || echo "*** GENHDLIST FAILED ***" exit 0

	Important note for RedHat < 6.1
	The installation in RedHat 6.1 is completely changed from earlier versions, and RedHat has introduced anaconda. The genhdlist program is now found in a different place, so in the script above, we used GENHDDIR=${RHROOT}/${ARCH}/misc/src/anaconda/utils while for releases up to (and including) 6.0 that line should read GENHDDIR=${RHROOT}/${ARCH}/misc/src/install

In some cases, genhdlist fails to run, because the executable is not statically linked. In such a case, you can add a new line ${RHROOT}/${ARCH}/RedHat/instimage/usr/lib in /etc/ld.so.conf and run ldconfig -v.

Another solution is to recompile genhdlist. The following modification to the updateHdlist script worked under RedHat 5.2:

#!/bin/bash RHVERSION=6.1 ARCH=i386 RHROOT=/misc/redhat/redhat-${RHVERSION} GENHDDIR=${RHROOT}/${ARCH}/misc/src/anaconda/utils echo Compiling genhdlist... sed -e 's/FD_t/int/' \ -e 's/fdOpen/open/' \ -e 's/fdClose/close/' \ -e 's/fdFileno//' < ${GENHDDIR}/genhdlist.c > /tmp/genhdlist.c cc -o /tmp/genhdlist -I/usr/include/rpm /tmp/genhdlist.c -lrpm -lz echo generating hdlist... chmod 644 ${RHROOT}/${ARCH}/RedHat/base/hdlist /tmp/genhdlist ${RHROOT}/${ARCH} || echo "*** GENHDLIST FAILED ***" exit 0

In this version of the script, a copy of the C source of genhdlist.c is piped through sed to create a copy in /tmp that will compile under RedHat 5.2. This version of genhdlist is then used to create the hdlist file

Important note for RedHat 5.2

As distributed with RedHat version 5.2 and earlier, genhdlist CRASHES if there are files in the RedHat/RPMS directory which are not RPM files! This causes problems, because in the 5.2 distribution, there are a couple of non-RPM files named ls-lR and ls-lR.gz in RedHat/RPMS. Therefore, you must remove all non-RPM files from the directory. Alternatively, you can apply the patch genhdlist.c.diff to misc/src/install/genhdlist.c and do a make. The patch will cause genhdlist to ignore any non-RPM files.

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5.3.1.2. Creating the CD iso image

You'll need to create an image file which will be written to the CD. This file will be 500Mb or more so find a partition with enough free space. You may need to be root to use mount and cdrecord. Here you will prepare the iso image of the bootable CD to be burned. It is actually, not strictly necessary, to create a bootable CD, because you could use a boot floppy instead of it, but it's definitely a nifty feature (and makes your disc more similar in behaviour to the original one). These are the commands I use to complete the task:

$ mkdir /images-destination-dir $ mkisofs -r -J -T -v -V "Red Hat 6.1 (Hedwig)" \ -c boot.cat -b images/boot.img \ -o /images-destination-dir/i386-disc.iso .

This is needed to burn the (bootable) disc and is executed from the top level directory of the distribution. The /images-destination-dir directory is the container for the iso image you are generating, and it must exist (obviously) before starting the procedure. In the following table you can read a brief explanation of the various options and their meanings (most of it was extracted from the mkisofs man page).

Table 1. mkisofs options and parameters

-r		Rock Ridge extensions with useful values for the permission bits
-J		Joliet extensions to use the cd with some different operating systems
-T		Generate a TRANS.TBL file in each directory to map correctly the file names even on systems which do not support the Rock Ridge extensions.
-v		be verbose
-V <volid>		Specifies the volume ID (volume name or label) to be written into the master block.
-c <boot catalog>		Specifies the path and filename of the boot catalog to be used when making an "El Torito" bootable CD. The pathname must be relative to the source path specified to mkisofs.
-b <eltorito boot image>		Specifies the path and filename of the boot image to be used when making an "El Torito" bootable CD. The pathname must be relative to the source path specified to mkisofs and specify a floppy image (which is why we use one of the floppy images found on the original CD. You may want to change this with the pcmcia.img image to install using pcmcia devices like network cards or CDROM readers.
-o <filename>		Name of the file containing the generated iso image
.		This is the root directory for our generated iso image (we are working from the root directory of every CD, so a dot is enough).

You will find details of how to burn the image on a media in Burning the CD. The mkisofs and cdrecord steps can be executed by means of a graphical frontend like X-CD-Roast which should currently support the creation of bootable CDs (I've never used it, so don't expect me to give you any explanation).

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5.3.3. RedHat 9, 8.0 and 7.3

Once again a lot of things have changed with the release of the 7.x series of the distribution. There are now more operations to complete to obtain a fresh and uptodate series of CDs. Exactly, they have become more than one with release 7.0 and now the tree has to be split to fit on the media. This is done by means of the splitdistro script, which is written in python like most of the anaconda installer. To complete this part, you must use a Linux RedHat 7.3, 8.0 or 9 machine with the anaconda-runtime package installed (it will probably have version 7.3.7, 8.0.4 or 9.0.4), depending on the release you want to rebuild. The procedure is composed by seven steps:

1. Regenerating the hdlist and hdlist2 files

2. Updating the comps.xml (or comps) file

3. Rebuilding the installer

4. Splitting the distribution in CD-sized chunks

5. Regenerating the hdlist and hdlist2 files (again)

6. Generating the iso images

7. adding and checking the md5 signatures in the iso images

All the steps are grouped together in a single script presented in the last section.

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5.3.3.1. Preliminary operations on the main tree

Some of the scripts included in the anaconda-runtime package need the main tree to be moved in a subdirectory named like the architecture we are building for (so i386/ for me). We will move everything to such directory before starting the procedure and change the invocation of the scripts which don't need this modification.

For redhat 9 and 8.0:

$ chmod -R u+w /absolute-path-to-toplevel-dir $ mkdir -p /absolute-path-to-toplevel-dir/i386 $ cd /absolute-path-to-toplevel-dir $ /bin/mv * i386

You should change "/absolute-path-to-toplevel-dir" with the absolute path of the directory where the root of your local copy of the distribution is located (maybe somewhere on some hard drive). You will get an error, from the execution of the last command, because the i386/ directory cannot be moved under itself, but you don't need to worry about that.

For redhat 7.3:

$ chmod -R u+w /absolute-path-to-toplevel-dir $ mkdir -p /absolute-path-to-toplevel-dir/i386 $ cd /absolute-path-to-toplevel-dir $ for i in `ls` ; do [ $i != "SRPMS" -a $i != i386 ] && /bin/mv $i i386 ; done

You shouldn't receive any error message this time from the last command (hopefully).

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5.3.3.2. Regenerating the hdlist and hdlist2 files

This is done by means of the following two commands with the help of the genhdlist program.

$ /usr/lib/anaconda-runtime/genhdlist /absolute-path-to-toplevel-dir/i386 $ chmod 644 /absolute-path-to-toplevel-dir/i386/RedHat/base/hdlist{,2}

Once again, "/absolute-path-to-toplevel-dir" is the absolute path of the directory where the root of your local copy of the distribution is located. The second command is needed to make sure the correct permissions are set for the file. You should already have an idea of what these files are about if you have read through The Redhat directory.

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5.3.3.3. Update the comps.xml file

In Redhat Linux 8.0 the format of the comps file has completely changed and it's now based on XML. It provides much more flexibility and ease of customization as you can read in The comps file. If you have modified or intend to modify the list of the installed packages, you need to complete this step. This, in turn, implies having the modified version of comps-9.tar.gz comps-9.tar.gz (the original one doesn't work for me) or comps-8.0.tar.gz package (depending on the release you are building) including the master comps file found on the Redhat website and the comps-extras rpm package installed. Follow these steps for Redhat 9 and 8.0:

$ cd /some-dir-of-your-choice $ tar xzvf /path-to-comps-9.tar.gz/comps-9.tar.gz $ cd comps $ make $ cat comps-milan.xml |sed 's!</comps>!!g' >comps-tmp.xml $ /usr/share/comps-extras/getfullcomps.py comps.xml \ /absolute-path-to-toplevel-dir i386 >> comps-tmp.xml $ echo '</comps>' >> comps-tmp.xml $ cp comps-tmp.xml /absolute-path-to-toplevel-dir/i386/RedHat/base/comps.xml

Beside "/absolute-path-to-toplevel-dir", you should take care of assigning valid names to "/some-dir-of-your-choice" and "/path-to-comps-9.tar.gz". The rest of the commands can be just copied. And... you must (obviously) change 9 to read 8.0 if you are building a Redhat 8.0 distribution.

Again, before issuing the make command, you should modify the file comps-milan.xml.in using your favourite text editor and following the guidelines and the suggestions found in The comps file and on the anaconda comps section of the Redhat website.

The script presented in the last section will execute all the steps needed after the make command, using the COMPSFILE variable to find the comps-milan.xml file (it doesn't need to have that name, I'm just using the original name, but you can change it if you want).

If you are using Redhat 7.3, the comps file (have you noticed the different name...) is a textual file with a completely different syntax described in some more detail in The comps file. In this case, the only necessary operations are modifying the file to suit your needs and copying it to the RedHat/base/comps file in the main tree overwriting the original one.

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5.3.3.4. Rebuilding the installer

This will rebuild the anaconda installer in your local copy of the distribution using your updated packages. For Redhat 9 execute:

$ /usr/lib/anaconda-runtime/buildinstall \ --pkgorder /absolute-path-to-toplevel-dir/pkgorder.txt \ --comp dist-9 --product "Red Hat Linux" --version 9 \ --release "Redhat 9 (Shrike)" /absolute-path-to-toplevel-dir/i386

Where, once again, "/absolute-path-to-toplevel-dir" is the directory where the root of your local copy of the distribution is located.

For Redhat 8.0, the procedure is pretty much the same (the "--product" option is missing):

$ /usr/lib/anaconda-runtime/buildinstall \ --pkgorder /absolute-path-to-toplevel-dir/pkgorder.txt \ --comp dist-8.0 --version 8.0 --release "Redhat 8.0 (Psyche)" \ /absolute-path-to-toplevel-dir/i386

Or if you are still using Redhat 7.3 (as I am):

$ /usr/lib/anaconda-runtime/buildinstall \ --pkgorder /absolute-path-to-toplevel-dir/pkgorder.txt \ --comp dist-7.3 --version 7.3 /absolute-path-to-toplevel-dir/i386

The absence of the (mandatory in 8.0) --release option is the only noticeable difference.

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5.3.3.5. Split the distribution

This will create five directories, each one corresponding to a different CD and will put in them hard links to the real files contained in your local copy of the distribution.

This will not work at all for Redhat 7.3 if you don't use the modified version of the splitdistro script reported in the next paragraph. For Redhat 8.0 and 9, a modified version of splitdistro is provided mainly because even if the problems in the previous script were fixed, the execution now fails if there are not enough packages to fill all the CDs (the first four completely and the last one even just partly).

$ $/usr/lib/anaconda-runtime/splitdistro \ --fileorder /absolute-path-to-toplevel-dir/pkgorder.txt --release \ "Redhat 9 (Shrike)" /absolute-path-to-toplevel-dir i386

The only thing you need to change for 8.0 and 7.3 is the string passed to the --release option (which should read "Redhat 8.0 (Psyche)" or "Redhat 7.3 (Valhalla)")

For Redhat 7.3 the version of the splitdistro7.3 (python) script used was extracted from the anaconda-runtime 7.3.7 package and modified by me. You should sustitute it to the original one (maybe after copying the latter) named /usr/lib/anaconda-runtime/splitdistro.

The only modification (apart from some small fixes), the script went through, is a change in its behaviour if the SRPMS directory is not found (doesn't terminate, but generate the CDs without source packages).

For Redhat 8.0 the version of the splitdistro8.0 (python) script used was extracted from the anaconda-runtime 8.0.4 package and modified once again by me to obtain some improvements I felt the need for. You should sustitute it to the original one (maybe after copying the latter somewhere) named /usr/lib/anaconda-runtime/splitdistro. Anyway, the original one works well, if you want to build a distribution which has all the SRPMS packages (so to fill all the 5 CDs otherwise the script will fail).

The only modification the script went through is a change in its behaviour if the SRPMS directory is not found (doesn't terminate failing, but generates the CDs without source packages) or there is one CD which hasn't any package on it (instead of failing, generates an empty directory).

For Redhat 9 you can find a copy of the script with the same modifications applied to the version included in release 8.0 here: splitdistro9. Everything said for Redhat 8.0 in the previous paragraph applies to release 9.

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5.3.3.6. Regenerating the hdlist and hdlist2 files

This is needed to recreate the hdlist and hdlist2 files, using some of the informations obtained in the previous steps. There are no differences between 7.3, 8.0 and 9 for this execution of the program The command to issue is the following:

$ /usr/lib/anaconda-runtime/genhdlist \ --fileorder /absolute-path-to-toplevel-dir/pkgorder.txt --withnumbers \ /absolute-path-to-toplevel-dir/i386-disc[1-3]

As you can see, there are two new options passed to the program, if you remember the first run of it. The first one, --fileorder, tells genhdlist to use the file pkgorder.txt we generated in the second step (rebuild the installer). This file keeps informations on how the packages were split on the different CDs and is used by the installer to determine in which order the packages should be installed. Basically, if you avoid using it, you will (probably) end up swapping the various CDs many times during the installation. The --withnumbers option is needed to associate a CD number to every package (as you can see, a wildcard indicating the first 3 iso images is used).

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5.3.3.7. Generating the iso images

Here you will prepare the iso images to be burned on the actual CDs. There are two different commands to be used for the first disc and for the rest of them. This is due to the need of obtaining a first CD which is bootable. This is actually, not strictly necessary, because you could use a boot floppy instead of it, but it's definitely a nifty feature (and makes your discs more similar in behaviour to the original ones). These are the commands I use to complete the task:

$ mkdir /images-destination-dir $ mkisofs -r -J -T -v -V "Red Hat 9 (Shrike) disc 1" \ -c isolinux/boot.cat -b isolinux/isolinux.bin -no-emul-boot \ -boot-load-size 4 -boot-info-table -o /images-destination-dir/i386-disc1.iso .

This is needed to burn the first (bootable) disc for RedHat 8.0 and 9 (with no floppy emulation) and is executed from the top level directory of the distribution. The /images-destination-dir directory is the container for the five iso images you are generating, and it must exist before starting the procedure. The only thing which needs to be changed for Redhat 8.0 is the volume name (it should be "Red Hat 8.0 (Psyche) disc 1").

$ mkdir /images-destination-dir $ mkisofs -r -J -T -v -V "Red Hat 7.3 (Valhalla) disc 1" \ -c boot.cat -b dosutils/autoboot/boot.img \ -o /images-destination-dir/i386-disc1.iso .

This is needed to burn the first (bootable) disc on 7.3 and is executed from the top level directory of the distribution (this time with floppy emulation).

The rest of the images can be written by means of this "for" loop

$ for i in `echo 2 3 4 5` ; do mkisofs -r -J -T -v \ -V "Red Hat 9 (Shrike) disc ${i}" \ -o /images-destination-dir/i386-disc${i}.iso . ; done

The loop just presented will prepare the last four images giving them the correct numbers. As you can see, there are just two missing options from the first run, and, as you can guess, they are needed only to create a bootable CD. In Creating the CD iso image, you can read a brief explanation of the various options and their meanings (most of it was extracted from the man page). Again if you are building a Redhat 8.0 you should change the volume name to read "Red Hat 8.0 (Psyche) disc ${i}".

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5.3.3.8. Implant and check the md5 signatures in the iso images

This is actually an optional step but it permits the use of the "checkmedia" option to verify the CDs signatures before installing them, so to guarantee their correctness.

The following commands permit to inject and verify an md5 signature on an iso image:

$ /usr/lib/anaconda-runtime/implantisomd5 iso-image $ /usr/lib/anaconda-runtime/checkisomd5 iso-image

After completing all these steps, we will find ourselves with the five CD images to burn. Considering that typing all this stuff is a bit time consuming, in the next section is presented a script, which will complete all of the listed operations in a single run (do not forget to configure the parameters properly).

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5.3.3.9. Putting all the steps together

The updateBuild.sh script will execute all the steps needed to rebuild the distribution CDs for RedHat 7.3, 8.0 or 9 in a single run (as root). Before using this script you have to configure the rhcd.conf configuration file after exporting a RHCDPATH variable pointing to the directory where this file is. If you want to include a modified comps.xml (or comps) file in your CDs as explained in The comps file, you should copy it into the location defined by means of the COMPSFILE variable now (before executing the script). Don't forget to add the modified splitdistro script to the /usr/lib/anaconda-runtime directory if you need it.

# export RHCDPATH=/home/luigi/tmp/rhcd-scripts # sh updateBuild.sh

6.1. Test the image(s)

If you're paranoid, you can test your new disk image(s) 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. The (optional) test can be done by issuing the command:

# mount -t iso9660 -o ro,loop=/dev/loop0 iso-image /mnt/cdrom

Where "iso-image" is the name you gave to the iso image file to be mounted (which is the only one for releases up to and including 6.2). When you're done, don't forget to unmount it

# umount /mnt/cdrom

6.2. Burn the disk(s)

Be sure to set the correct parameters for your device. This command, for example, is for a 4X CDR, which is quite slow, by the way. Moreover, it is assumed that the CD writer is on SCSI bus 0, with ID number 0 and LUN 0 (you can obtain these values by issuing a cdrecord -scanbus and assign them to the -dev= parameter).

# cdrecord -v speed=4 dev=0,0,0 /images-destination-dir/disc1.img

7.1. Format of comps file in RedHat versions < 6.1

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 should be the same by convention).

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).

7.2. Format of comps file in RedHat version 6.1

With RedHat version 6.1, the format of the comps file has changed. The decoding takes place in ${RHROOT}/${ARCH}/misc/src/anaconda/comps.py. I didn't analyze yet this python script and the following rules were obtained only by reading the file and testing some configurations for it.

In release 6.1, the definition of component is extended to include some more optional elements beside the <RPM> ones. These elements are:

<arch-dependent-RPM 1> ... <arch-dependent-RPM n> <required-component 1> ... <required-component n> <component-dependent-RPM 1> ... <component-dependent-RPM n>

An <arch-dependent-RPM> defines a dependency between a package and specific architecture and has the following definition:

(!)?arch: <RPM>

So it can, for example, present itself, in the real world, as:

!alpha: kernelcfg

which means: if architecture is not alpha then install package kernelcfg.

Or as:

i386: mkbootdisk

which means if architecture is i386 then install package mkbootdisk

A <required-component1> enforces the dependency from another component and is defined as:

@ <component>

So, for example, if inside a component definition you find the following line:

@ Networked Workstation

it means that the component itself needs the installation of another component named Networked Workstation.

A <component-dependent-RPM> is used to select the installation of some additional packages for a component, given the presence of another component. Its definition is as follows:

? <component> { <RPM 1> ... <RPM n> }

So if, for example, in a component definition, you happen to read the following lines:

? KDE { kpppload }

then if the KDE component is installed, the package kpppload will be installed together with the packages included in the component the definition was found in.

7.3. Format of comps file in RedHat version 6.2

With RedHat version 6.2, the format of the comps file has, apparently, changed just slightly. The decoding takes place in ${RHROOT}/${ARCH}/misc/src/anaconda/comps.py even in this case. Once again, I didn't analyze yet this python script and the following rules were obtained only by reading the file and testing some configurations for it.

In release 6.2, the definition of component is extended to include two more optional elements which are:

<lang-dependent-RPM 1> ... <lang-dependent-RPM n> <arch-dependent-component 1> ... <arch-dependent-component n>

A <lang-dependent-RPM> is needed to specify the installation of a package in case a specific language was selected. It's defined as:

(lang <language>): <RPM>

For example, the following line:

(lang ja_JP)): locale-ja

means: if the Japanese language is selected, then install the locale-ja package together with the other packages installed for the current component.

An <arch-dependent-component> extends the concept of <arch-dependent-RPM> introduced in release 6.1 to an entire component, as you can understand reading the definition:

(!)?arch: <component>

7.4. Format of comps file in RedHat version 7.3

With RedHat version 7.3, the format of the comps file has gained some more syntactical power. The decoding takes place (again) in the comps.py script, which you can now find in the /usr/lib/anaconda/ directory if you have installed the anaconda package. The dependencies on a language or an architecture by a component or a package can now be joined with the and operator. For example:

(arch !s390 and arch !s390x and arch !ia64): readline2.2.1

which means if architecture is not any of s390, s390x, ia64 then install the package readline2.2.1. This can be done with components instead of packages and languages instead of architectures. All this, is definitely more than enough for the simple examples of customization of the default installation which will be presented in the next section.

7.5. Format of comps file in RedHat version 8.0 and 9

With RedHat version 8.0 and 9, the format of the comps file has changed completely and now an XML file, whose name is comps.xml, is used. Details on the file syntax can be found in the anaconda comps section of the RedHat website.

8.1. Booting from a bootable CD

Most modern machines are able to boot directly from a CD, provided it is made bootable with the procedure outlined in section Creating the CD iso image. Often, however, you need to change the setting of the BIOS to make the CD drive bootable. See the documentation for your mother board to see how it's done.

10.1. Related documentation

10.2. Acknowledgements

Apart from those mentioned above, thanks are given to the following people for valuable input, feedback, discussions and other: