Customize RedHat 7 Installation

This article is built on top of all the articles listed in the reference section. You are strongly recommended to go over all of them before go on reading this article.

Special thanks to Gray Watson, author of "Customized RedHat Linux Kickstart Installation Cdrom" and Tony Nugent ("The (unofficial) RedHat 7 Customised Installer mini-HOWTO"). Without their renovative experience, there won't be this article. More over, I've "borrowed" lots of materials from their article, sometimes even the whole paragraph is copied over. :-) If you don't have much time, you should at least read Gray's "Customized RedHat Linux Kickstart Installation Cdrom" first. It is the most clear and concise article I've read so far.

Choose "Hard Drive" option to install Red Hat Linux from a hard drive. Two text entry boxes for hard drive partition and hard drive directory will appear. Enter the hard drive partition that contains the ISO images (for example, /dev/hda1) in the Hard Drive Partition text box, and enter the directory that contains the ISO images in the Hard Drive Directory text box.

If you don't have enough space on your PC, the next mininum-hassle solution is to find a Linux box, loop mount the disk images and make them accessible from http. All decent Linux distro have loop mount and web server features ready for use. But a PC with a big empty HD space is strongly recommended. The following paragraph assumes that you have enough empty spaces on HD (~3G).

Caution, RH7.3 has a bug in its installation. I have no problem installing from hard drive using hda1. But when I try to reinstall the second time, RedHat refuses to list /dev/hda1. All I can choose is the Linux partitions. Darn! What sense it makes if the only places I can pick the images are those I am going to destroy?

So I recommend that you make at least two Linux volumes. One for root volume, and the other for the /export volumn. Copy the image files into the /export volumn right after the installation, in case you need to reinstall again. And preserve the /export in the following installations.

This is what I've been doing. Several small (2G) volumes for various flavor/version of Linux, and one big /export volume to share my home accross all of them. It also makes upgrading/testing the OS quite easy.

Gray Watson suggested to use "trim down" approach to select your own rpms:

Boot into Linux, loop mount the installation ISO images. Copy each of of them into the same place that you've picked.

# Load the first CD into the drive
mount -o loop /sourcepath/valhalla-i386-disc1.iso /mnt/cdrom
mkdir /somepath/cdrom_files
cd /mnt/cdrom
tar -cf - . | ( cd /somepath/cdrom_files ; tar -xvpf - )
cd /somepath/cdrom_files
umount /mnt/cdrom

# Repeat the above steps for disk2 & 3.
mount -o loop /sourcepath/valhalla-i386-disc2.iso /mnt/cdrom

He then went on:

"The next stage of the process is to trim down the list of packages until you get below the 700mb that will fit onto one CD. In general, I sorted the RedHat/RPMS directory by size and started at the top and moved down removing the rpms that I knew I did not need. You need to be careful here because there are dependencies between packages that aren't always expected. Someone probably has a tool to resolve dependencies but I don't know about it…

"If you rebuild the hdlist file, make the CD, and try to install and it prompts for the 2nd CD in the set then you missed a dependency. I'm not sure if or how you can tell which package is the specific problem. "

Resolve RedHat rpms' dependencies had always been a painful headache to me. More over, I haven't been paying close attention what rpm packages had been install on my system before, and what rpms I do not need. For example, I didn't know if I need the following rpms or not up until very recently: specspo, cyrus-sasl, ORBit or cURL.

So, what I did basically is to carefully select what I need during RedHat installation and include all the installed rpms in my customized CD:

cd /mnt

mkdir iso{1,2,3,4,5} rpms-org rpms-pck

mount -o loop /export/rh73/valhalla-i386-disc1.iso /mnt/iso1
mount -o loop /export/rh73/valhalla-i386-disc2.iso /mnt/iso2
mount -o loop /export/rh73/valhalla-i386-disc3.iso /mnt/iso3

cd rpms-org
ln -s ../iso1/RedHat/RPMS/*.rpm .
ln -s ../iso2/RedHat/RPMS/*.rpm .
ln -s ../iso3/RedHat/RPMS/*.rpm .

cd ../rpms-pck
rpm -qa | sed 's|^|ln -s ../rpms-org/|; s/\s*$/*.rpm ./'
!! | sh

cd ..
tar -h -czf rpms-pck.tgz rpms-pck

Now, I've got all the installed rpms on my system in rpms-pck.tgz file.

In practice, I hand-crafted my own kickstart configuration file to select the very rpms that I really need. For example, all tools from the "Software Development" package group, but not any "-devel" rpms from it. If you don't want to go this far (to be so prefect), following my above steps would be definitely enough.

In the RedHat/base directory on the 1st CD is the comps file which is what anaconda reads when it displays the various packages of RPMs. It is also used used by the %packages section of the ks.cfg file. An example the comps file is:

4

1 Base {
  MAKEDEV
  anacron
  ...
}

0 --hide Network Server {
  @ Network Support
  (arch !i386): vnc
  finger-server
  ? X Window System {
    i386: compat-libstdc++
    libpcap
  }
  ...
}

The leading 4 means the format version of the comps file.

The "1 Base {" defines a collection of RPMs associated with the Base package. The 1 means that it is enabled by default. The "0 —hide Network Server {" defines the Network Server package which is off by default. The "—hide" means that it should be hidden from the user's package selection tool in anaconda.

The "@ Network Support" line means that the "Network Server" package includes the "Network Support" package. The "(arch !i386") line allows certain packages to be installed if (or in this case if not) installing on specific architecture. The "? X Window System {" line means that if X windows is installed then the packages in subsection are included in Network Server package.

In any case, by looking at this file, you can see which RPMs you use when you install a Network Workstation and which ones are candidates for removal if you don't install X11 stuff.

Further tuning can be done, for example to add an entry for any extra rpms that you specifically want to install:

0 --hide Extras {
   numlock
   xcdroast
   taper
   etc...
}

From "Building a kernel for AARNet Dell machines" http://www.aarnet.edu.au/redhat/build.txt

The "comps" file format is not documented, but is reasonably obvious. The mysterious "4" at the top of the file is a version number for the file format. The sections are of the basic form

<wanted> <options> <component> {
  <dependency>
  ...
  <package>
  ...
  <optionalpackage>
  ...
}

Where <wanted> is 1 where the package defaults to being installed, 0 otherwise. <package> is the RPM package.

<options> ::= <nil>
<options> ::= --hide

<dependency> ::= <nil>
<dependency> ::= @ <component>

<optionalpackage> ::= ? <dependency> {
                        <package>
                        ...
                      }

All lines appear to have the form

<condition>: <text>

<condition> ::= <nil>
<condition> ::= !<condition>
<condition> ::= <architecture>:
<condition> ::= (<expr>):
<expr> ::= <term>
<expr> ::= <term> and <term>
<term> ::= arch <architecture>
<term> ::= arch !<architecture>
<term> ::= lang <language>
<term> ::= lang !<language>
<architecture> ::= i386 | ia64 | sparc | alpha
<language> ::= <lang>[_<region>[.<codeset>]]
<lang> ::= ja | cs | pl | ro | sl | sk | tr | uk | ru | ...
<region> ::= BR | CN | HK | TW | GB | CA | ES | ...
<codeset> ::= gb2312 | ...

I've hacked another Perl tool, to clearn out from the comps file the packages that you have not selected. It is at http://xpt.sf.net/techdocs/linuxsm/CustomizeInstallation/tools/compsClean.pl. Again, this might not be necessary, Gray Watson didn't do it when building his own RH7.2.

The usage is simple:

compsClean.pl [architecture] [comps file] [path to rpms]

For example:

compsClean.pl i386 RedHat/base/comps /export/rpms/rpms-pck > /tmp/comps.new

Then you can copy the "comps.new" over the old "comps", of course after doing a diff on them.

Do this to check the internal md5 checksum of each rpm package to make sure that they are all intact:

cd /export/linux/7.3/en/os/i386/RedHat/RPMS
rpm -K  --nopgp --nogpg *.rpm | grep "NOT OK"

In the base directory, there 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 or add your own packages to the RPMS directory, you need to update hdlist.

Once you have removed certain RPMs from the directory and done updating rpms, you will need to rebuild the hdlist file. The file hdlist lists which RPMs are available on the first CD, and the file hdlist2 is for the second CD. You will need to build the genhdlist utility which is included in the anaconda source release. Available from any redhat mirror site, at

/…/ftp.redhat.com/linux/7.3/en/os/i386/SRPMS/anaconda-7.3-7.src.rpm

rpm -ih anaconda-7.3-7.src.rpm
cd /usr/src/redhat/SOURCES
tar -xjf anaconda-7.3.tar.bz2

In the utils directory in the source tarball, should be the genhdlist.c which should be buildable with make genhdlist.

cd anaconda-7.3/utils/
make genhdlist

Once you've built the genhdlist tool, go to the root path of your future cdrom system:

cd /export/linux/7.3/en/os/i386

rm -f RedHat/base/hdlist*
genhdlist --withnumbers --hdlist RedHat/base/hdlist `pwd`
ls -l RedHat/base/hdlist*

Please note

This is optional. It requires a tools listed in the later "Helpful tools" part. I include them here to show how I did the test. The reason doing this is that hdlists are binary files. You can't compare them directly.

dumphdrlist.py RedHat/base/hdlist | less

dumphdrlist.py /mnt/iso1/RedHat/base/hdlist > /export/baks/hdlist.o1
dumphdrlist.py /mnt/iso1/RedHat/base/hdlist2 > /export/baks/hdlist.o2

dumphdrlist.py /export/linux/7.3/en/os/i386/RedHat/base/hdlist > /export/baks/hdlist.n1
dumphdrlist.py /export/linux/7.3/en/os/i386/RedHat/base/hdlist2 > /export/baks/hdlist.n2

diff -wu /export/baks/hdlist.o1 /export/baks/hdlist.n1 | less
diff -wu /export/baks/hdlist.o2 /export/baks/hdlist.n2 | less

If you need to copy files off of the install media to the new installation then you'll need to do something like the following:

%post --nochroot
# the --nochroot is necessary to not change root into the new installation
# cp /mnt/source/dir/file /mnt/sysimage/dir/file
# where /mnt/source is the install media
# and /mnt/sysimage is the new installation

# Use my very own profile
cp /mnt/source/customized/profile /mnt/sysimage/etc/profile
# My extra can't-live-without tools
cp /mnt/source/customized/opt.tgz /mnt/sysimage/

The beginning of this section is signified by the %post directive in the KickStart config file. In what follows you can take advantage of all of the utilities which have been installed on your newly built Linux system, and operated on the real root file system.

For example, setup crontab jobs by creating root crontab entries as files in one or more of the directories /etc/cron.hourly, /etc/cron.daily, /etc/cron.weekly and /etc/cron.monthly.

Mine is:

%post

# turn off packages that we don't want running
echo Turning off some packages
/sbin/chkconfig --level 0123456 isdn off
/sbin/chkconfig --level 0123456 nfslock off

echo Turning on some packages
/sbin/chkconfig --level 345 httpd on
/sbin/chkconfig --level 345 postgresql on
/sbin/chkconfig --level 345 rsync on
/sbin/chkconfig --level 345 wu-ftpd on

echo Change firewall from ipchains to iptables
chkconfig --level 12345 ipchains off
chkconfig --level 345 iptables on

/bin/bash -c 'rm -f /root/.bash_logout'

/bin/echo "/opt/bin/guide &" >> /etc/rc.d/rc.local

Refer to Tony's article for a full script creating iso9660 disk images. Also available at my local copy "Bare bone RedHat 7 Customised Installer" http://xpt.sf.net/techdocs/linuxsm/CustomizeInstallation/linuxsm01.003.html#section-1.

Note, mkisofs will show the following warning:

Warning: creating filesystem that does not conform to ISO-9660.
Using XFREE000.RPM for  RedHat/RPMS/XFree86-ISO8859-15-100dpi-fonts-4.2.0-8.i386.rpm (XFree86-100dpi-fonts-4.2.0-8.i386.rpm)
Using XFREE001.RPM for  RedHat/RPMS/XFree86-100dpi-fonts-4.2.0-8.i386.rpm (XFree86-4.2.0-8.i386.rpm)

This is normal, because we are generating Joliet directory records in addition to regular iso9660 file names. Also, we will have long file names on CD (e.g., XFree86-100dpi-fonts-4.2.0-8.i386.rpm) instead of short ones like XFREE000.RPM. Use the technique in the next topic to verify it.

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.

Note,

If any of above links does not work by the time you read this article, you can find a local copy here:

http://xpt.sf.net/techdocs/linuxsm/CustomizeInstallation/mirrored

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.

Also, Anaconda offers some tools that help to ensure that things are ok.

The python script /usr/lib/anaconda-runtime/check-repository.py can be used to check the RedHat/base/comps file to ensure that it is consistent with the contents of the RedHat/RPMS/ directory. However, comment out the "import todo" entry (around line 38) before you use it. (Thanks to Forrest Taylor <forrestx.taylor@ intel.com> for this hint).

Seth has some more gems available at http://www.dulug.duke.edu/treetools/…

dumphdrlist.py is a python script written by Jeremy Katz (<katzj@redhat.com>) that looks at the RedHat/base/hdlist file and lists which installation disk a particular rpm is on. From Jeremy: "Usage is simple enough — 'dumphdrlist.py /path/to/hdlist' and it will then print the NEVRA of all of the packages as well as the disc it's on in the format" http://www.linuxworks.com.au/dumphdrlist.py.txt