Making a new distribution based on PCLinuxOS

2006-06-07
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PCLinuxOS >

Create your own PCLinuxOS-derived Linux distribution.

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Introduction ∞

You can create a new livecd that can install to reproduce most (or all) of your current PCLinuxOS installation.

By adding and removing packages, or changing any files, you can customize the distribution.

With the right knowhow, mklivecd is a simple way to make a "new" Linux distribution. With significant work, your remaster could totally diverge from its PCLinuxOS roots. However, a basic remaster really isn't a new distribution.. it's more of an homage to PCLinuxOS, with a bit of personalization.

A remaster that works on older computers ∞

There are two types of kernels:

  • normal -- Optimised for newer computers (i586 and better).

  • lve -- Optimised for older computers (i386 and better) but not newer computers.

The original PCLinuxOS LiveCD is made using the lve kernel so that it will work on older computers. However, when you install it and then update your system, you will end up using the normal kernel (FIXME - Is this true?).

When you create your own LiveCD, it will use your existing kernel by default.

  • TODO - Write up some advice on switching kernels. Link to a howto if possible.

Working with packages ∞

It's probably a good idea to update an installation before remastering it, so it's in tip-top shape.

Sure, you could log into X, run Synaptic, reload, mark upgrades and apply.. but on the console, I do:

# As root

# Update all packages
# WARNING: In theory, updating can break things!
# Consider backing up before, and rebooting then testing after.
apt-get autoclean && apt-get update && apt-get dist-upgrade

Removing packages you don't ever use is probably a good idea to reduce the size of your installation and therefore the resulting mklivecd ISO. I use synaptic for this, and I keep a careful eye on the dependancies so I don't remove things I really do need.

Pre-remaster preparation ∞

2008-08 - updated for PCLinuxOS 2007

When you have a PCLinuxOS installation which you would like to remaster into its own liveboot CD, what kinds of things should be considered?

  • Your users stay, including their passwords and all files in their home folders. This includes all cached files, command history and the like.

My intention is to wrap this into a script. I should even be able to build it as an RPM which is designed to perform these actions, and then fail to install. I can also put this into the PCLinuxOS contrib repository as some kind of apt-get install cleanup command.. which would rock.

I have users root, user and guest. Your system may be different and you will need to modify this script for your system. Yes it could be made much more intelligent. However, I would sooner rewrite it as a Ruby script than get technical with Bash. =)

This manual application cleanup could be supplemented by software:

manual cleanup script 

# as root

# Update all packages
# WARNING: In theory, updating can break things!
# Consider backing up before, and rebooting then testing after.
# I prefer to do this manually..
# apt-get autoclean && apt-get update && apt-get dist-upgrade

# Delete all files, but don't delete any directories:
find /var/cache/apt/       -name '*' -exec rm {} \;
find /var/log/             -name '*' -exec rm {} \;
find /var/state/apt/lists/ -name '*' -exec rm {} \;

# I have not tested this 'old kernels' cleanup:
# Clean up kernel headers and kernel modules from old kernels (if any)
KERNEL_VERSION=`uname -r`
OLDPWD=`pwd`
cd /usr/src
DELETE_HEADERS=`ls -1 /usr/src/|grep -i "linux-2*"|grep -v $KERNEL_VERSION`
rm -rf $DELETE_HEADERS
#
cd /lib/modules
DELETE_MODULES=`ls -1 /lib/modules/|grep -v $KERNEL_VERSION`
rm -rf $ DELETE_MODULES
cd $OLDPWD

# Remove everything out of /usr/share/doc except the HTML directory.
mv /usr/share/doc/HTML /;rm -rf /usr/share/doc/*;mv /HTML /usr/share/doc/

# Delete and recreate the guest account:
# if [TYPE != "BACKUP"] then:
  userdel -r guest
  useradd -g guest -d /home/guest -s /bin/bash -c "Guest Account" -m -k /etc/skel -p guest guest
  # I'm not sure how to just make this run automatically with my preferences.
  nohup kcmshell privacy & > /dev/null
# fi

# Clean up after 'links'
rm -f /home/user/.links/links.his
rm -f /home/user/.links/cookies
rm -f /root/.links/links.his
rm -f /root/.links/cookies

# Clean up after 'Firefox 3'
cd /root/.mozilla/firefox/*.default
rm -rf Cache*
rm -f cookies.sqlite downloads.sqlite search.sqlite sessionstore.* formhistory.sqlite
cd minidumps;rm -rf *
#-
cd /home/user/.mozilla/firefox/*.default
rm -rf Cache*
cd minidumps;rm -rf *
rm -f cookies.sqlite downloads.sqlite search.sqlite sessionstore.* formhistory.sqlite

# Clean out the .thumbnails directory
rm -rf /root/.thumbnails/*
rm -rf /home/user/.thumbnails/*

# umount all partitions except the main partition
umount /mnt/*

# locate/slocate's database
updatedb -v

rm -f /home/user/.bash_history
rm -f /root/.bash_history

mklivecd new.iso --bootopt splash=silent --bootkey F2=advanced.msg --bootimg boot.lss

Notes:

  • How do I clean out the /tmp directory safely?
  • Clear out Mozilla Firefox saved passwords.

  • Lynx doesn't appear to need cleanup.. I can't find any lynx-related files after using it.

Generating the LiveCD ∞

mklivecd new.iso

Yeah, that's it. Isn't Linux great? For more options, type

mklivecd --help

More advanced examples ∞

If you want to do something a bit fancier, you can have an initial splash, bootsplash and have the F2 key working on bootup:

mklivecd new.iso --bootopt splash=silent --bootkey F2=advanced.msg --bootimg boot.lss

Ignoring certain directories and files, specifying the working directory, the target directory and file, etc:

mklivecd \
  --nodir ^/root/temp,^/root/tmp,^/mnt,^/tmp,^/root/temp/livecd,^/root/livecd_iso \
  --nofile ^/etc/X11/xorg.conf,^/etc/X11/XF86Config,^/etc/modprobe.conf,^/etc/modeprobe.preload,^/etc/fstab \
  --root / \
  --workdir /root/temp/livecd \
  --bootopt splash=silent \
  --bootimg boot.lss \
  /root/livecd_iso/filename.iso

(Untested) Here's an example using the CVS version with $nodir and $nofile set, and uses this mklivecd command:

mklivecd \
  --nodir=^/root/temp,^/root/temp/livecd,^/root/livecd_iso \
  --nofile=/etc/X11/xorg.conf,/etc/X11/XF86Config,/etc/modprobe.conf,/etc/fstab, \
  /etc/resolv.conf,/etc/sysconfig/harddrake2/previous_hw,/etc/asound.state \
  --workdir /root/temp/livecd \
  --bootopt splash=silent \
  --bootimg boot.lss \
  --bootkey F2=advanced.msg \
  --md5sum \
  /root/livecd_iso/filename.iso

Omiting certain directories ∞

Note that the CVS version of livecd-utils has some advantages over the current version. See below for information on how to get, and use, the CVS version.

mklivecd documentation 

mklivecd supports --nofile and --nodir

   --nofile <ex1>[,][...]          Excludes files from the final image. (Also
                                   see the --nodir option for a full 
                                   description)
   --nodir <ex1>[,][...]           Excludes directories from the final image.
                                   Patterns passed to this option (as with the
                                   --nofile option) should be valid in a grep(1)
                                   search, e.g. --nodir=^/home/jaco,^/root/.mcop
                                   will exclude both the /home/jaco and 
                                   /root/.mcop directories from the final 
                                   LiveCD.

Example:

mklivecd \
  --nodir ^/root/temp,^/root/tmp,^/mnt,^/tmp,^/root/temp/livecd,^/root/livecd_iso \
  --nofile ^/etc/X11/xorg.conf,^/etc/X11/XF86Config,^/etc/modprobe.conf,^/etc/modeprobe.preload,^/etc/fstab \
  filename.iso

Alternately, because this seems to work:

cd ~
find|grep ^/*.*/[.]links/cookies

I'm fairly confident that you can omit certain files and directories like this:

mklivecd \
  --nodir ^/home/*.*/[.]thumbnails/, ^/root/[.]thumbnails/ \
  --nofile ^/root/[.]links/cookies, ^/root/[.]links/links.his, ^/home/*.*/[.]links/cookies, ^/home/*.*/[.]links/links.his \
  filename.iso

the CVS version ∞

I have not worked with the CVS livecd-utils. This is all untested.

To get and install the CVS livecd-utils:

mkdir /tmp/mklivecd
cd /tmp/mklivecd
cvs -d:pserver:anonymous@cvs.livecd.berlios.de:/cvsroot/livecd login
cvs -z3 -d:pserver:anonymous@cvs.livecd.berlios.de:/cvsroot/livecd co mklivecd livecd-utils
cd mklivecd
make;make install
cd ../livecd-utils/;make;make install
cd
rm -rf /tmp/mklivecd

Omitting certain directories ∞

(untested)

The CVS version of the mklivecd script uses the $nodirs and $nofiles parameters automatically.

$nodirs  = '^/[.].* ^/dev$ ^/initrd$ ^/lost+found$ ^/mnt$ ^/proc$ ^/sys$ ^/tmp$ ^/var/tmp$ ^/root/tmp$';
$nofile  = '^/[.].* ^/fastboot$ /core[.][0-9][0-9]*$ .*~$ .*[.]rpmnew$ .*[.]rpmsave$ [.]bash_history$ [.]fonts[.]cache-[0-9]$ [.]xauth.* [.]wh[.]* [.]xsession-errors$ ^/var/run/ ^/var/lock/subsys/';

The nodirs and nofiles specifies files and directories which don't participate in the livecd creation, these directories and files will be recreated during the livecd boot.

Notes and Issues ∞

Other files and directories to clean up ∞

find / -name ".wh*" -exec rm -f {} \;

I'm not sure what files these are. There may be a better way to clean up after them. When I search for these files, I see:

/var/lib/alsa/dev/snd/.wh.controlC0
/var/lib/alsa/dev/snd/.wh.pcmC0D0c
/var/lib/alsa/dev/snd/.wh.pcmC0D0p
/var/lib/alsa/dev/snd/.wh.pcmC0D1c
/var/lib/alsa/dev/snd/.wh.timer
/var/lib/alsa/dev/.wh.adsp
/var/lib/alsa/dev/.wh.audio
/var/lib/alsa/dev/.wh.dsp
/var/lib/alsa/dev/.wh.mixer

I don't want to delete things without understanding what they're doing.

I don't know how to not include certain users ∞

While it's possible to not include certain directories, I don't know how to not include an entire user.

I suspect that if I do this, it will still leave 'user' lingering around. Meaning that 'user' could log in but it has no home folder.

mklivecd \
  --nodir ^/home/user \
  /root/livecd_iso/filename.iso

Untested things ∞

CVS livecd-utils ∞

'old kernels' cleanup ∞

Other notes and issues ∞

One recommended command to generate the livecd is:

mklivecd new.iso --tmp=/mnt/sda6/tmp --bootopt splash=silent
  --bootimg=boot.lss --bootkey F2=advanced.msg --md5sum
  --fstab=rw,noauto
  --nofile=/etc/X11/xorg.conf,/etc/X11/XF86Config,/etc/modprobe.conf,/etc/fstab,/etc/resolv.conf,/etc/sysconfig/harddrake2/previous_hw,/etc/asound.state

What are the files that determine the "default" new user settings for KDE?

/etc/skel/.kde/share/config

If you want your custom settings to be for the default user then you would copy them into /etc/skel directory. Anything in that directory gets transferred to the new user.

If you go into the guest/root account and make your changes then build the livecd then yes they will show up just like they are on the hard drive. However if they install from the livecd to the hard drive and create a new user for themselves then no they will get the standard settings.

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