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# unsquashfs ovz-livecd/base/usrBe patient, this will take a few minutes.mo # this action takes some time, be patient ;)# mv squashfs-root/usr/ livecd-root/# rm -rf squashfs-root
# unsquashfs ovz-livecd/base/var.mo
# mv squashfs-root/var/ livecd-root/
# rm -rf squashfs-root
</pre>
This part contains detailed description of LiveCD creation. I've removed the output of some
commands in order to simplify the reading.
Note: before proceed with commands below, one needs to disable SE Linux on the host, otherwise rpm operations
in cdroot-ed environment described later on will fail due to inability to restore security file context. So, please,
do:
<pre>
# setenforce 0
</pre>
This will put SE linux in so-called 'permissive' mode, where all the blockers will be substituted by warnings.
If you wanna get rid of the warnings (rather annoying), the only way to do is to edit <tt>/etc/sysconfig/selinux</tt>
to read <tt>SELINUX=disabled</tt> and then reboot the host.
=== Creating booted LiveCD root filesystem ===
# cp mksquashfs /usr/bin/
# cd ~/workbench/-
# wget http://belnet.dl.sourceforge.net/sourceforge/squashfs/squashfs3.2-r2.tar.gz
# tar xzf squashfs3.2-r2.tar.gz
cc unsquashfs.o -lz -o unsquashfs
# cp unsquashfs /usr/bin/
# cd ~/workbench-
</pre>
Well, having the intruments in hand, why not extract the images? Create a directory, called <tt>livecd-root</tt>,
# mkdir livecd-root
# unsquashfs ovz-livecd/base/bin.mo # mv squashfs-root/for f in bin/ livecd-root/# rm -rf squashfs-root # unsquashfs ovz-livecd/base/etc.mo # mv squashfs-root/etc/ livecd-root/# rm -rf squashfs-root # unsquashfs ovz-livecd/base/lib.mo # mv squashfs-root/lib/ livecd-root/sbin usr var; do \# rm -rf squashfs-root # unsquashfs ovz-livecd/base/root$f.mo ; \# mv squashfs-root/root$f/ livecd-root/; \# rm -rf squashfs-root; \ done# unsquashfs ovz-livecd/base/sbin.mo # mv squashfs-root/sbin/ livecd-root</# rm -rf squashfs-rootpre>
Yet we have nearly complete root filesystem of '''booted''' LiveCD in <tt>livecd-root</tt> directory. However some things
are missing, and I guess you know what are they: <tt>/dev</tt>, <tt>/proc</tt>, <tt>/sys</tt>, <tt>/tmp</tt> and <tt>/boot</tt> directories. We need them, because some tools (<tt>rpm</tt>, <tt>bash</tt>, ...) will not work without them in chrooted environment later.
<pre>
# cd livecd-root# mkdir root/dev# cp -a /dev/* rootdev/dev# mkdir root/proc# mount -t proc proc root/proc/# mkdir root/sys# mount -t sysfs sysfs root/sys/# mkdir root/tmp# mkdir root/boot# cd -
</pre>
That's it. We have '''bootedbootstrapped''' LiveCD root filesystem in <tt>livecd-root</tt> directory.
Now we can <tt>chroot</tt> in this directory and install all needed packages. But what
packages do we need?
kernel of version other then 2.6.18 one is summarized below.
==== Peculiarities of building 2.6.9-rhel4 ====
* You should also include this path patch (http://git.openvz.org/?p=linux-2.6.18-openvz;a=commit;h=681d0b65dedd54d8c716cef56418ac1a478f94da)
in building process. Hopefully will be fixed in <tt>2.6.9-044stab044.8</tt> kernel.
* Use <tt>unionfs 1.0.14</tt>, but not <tt>unionfs 1.1.5</tt>, as offered at its official site!
* Small problems while building <tt>unionfs</tt>: arguments of <tt>vfs_permissions()</tt>. Just add <tt>NULL</tt>
to appropriate places.
==== Peculiarities of building 2.6.18-rhel5 ====
* Note, <tt>squashfs</tt> patch is already there, but you should use <tt>3.2</tt>! :)
==== Peculiarities of building 2.6.20 ====
* FIXMEOnly <tt>unionfs</tt> <tt>2.0</tt> is available for 2.6.20 kernel and it is distributed as a patch. Consequently modify <tt>spec</tt>-file and configs while building the kernel* <tt>unionfs</tt> <tt>2.0</tt> doesn't support unionctl. Consequently you have to modify <tt>liblinuxlive</tt> file on <tt>initrd</tt> image to mount all branches at once, but don't add them by ioctls.
=== Unionfs kernel module ===
<tt>tetex</tt>, <tt>latex</tt>, <tt>k3b</tt> and printing related packages:
<pre>
# cp -r to_booted_livecd/ livecd-root/tmp/# chroot livecd-root/
# rpm -e lksctp-tools-1.0.2-6.4E.1.i386
Clean it:
<pre>
# rm livecd-root/root/.bash_history
</pre>
Here we have to make one step to workaround [[Checkpointing and live migration]] problem. The thing is that at the moment
on this directory:
<pre>
mkdir livecd-root/vz/private/
</pre>
At the moment vzquota doesn't support <tt>tmpfs</tt> ([http://bugzilla.openvz.org/show_bug.cgi?id=558 Bug #558]).
<pre>
# rm -f ovz-livecd/base/*.mo
# mksquashfs root/lib/ ovz-livecd/base/for f in bin.mo -keep-as-directory# mksquashfs root/etc/ ovz-livecd/base/etc.mo -keep-as-directory# mksquashfs root/lib/ ovz-livecd/base/lib.mo -keep-as-directory# mksquashfs root/root/ ovz-livecd/base/root.mo -keep-as-directory# mksquashfs root/sbin/ ovz-livecd/base/sbin.mo -keep-as-directoryusr var vz; do \# mksquashfs root/usr/ ovz-livecd/base/usr.mo -keep-as-directory # it can take long...# mksquashfs root/var/ $f ovz-livecd/base/var$f.mo -keep-as-directory; \# mksquashfs root/vz/ ovz-livecd/base/vz.mo -keep-as-directory done
</pre>
than 8 characters) to kernel image, otherwise <tt>isolinux</tt> will not see it.
<pre>
# cp livecd-root/boot/vmlinuz-2.6.18-ovz028stab035.1-smp ovz-livecd/boot/ovz18
</pre>
Modify initrd image. More precisely, we need to add OpenVZ kernel modules there
# mount -o loop initrd-old mount-old/
# dd if=/dev/zero of=initrd bs=1048576 count=100
# mke2fs initrd
initrd is not a block special device.
Proceed anyway? (y,n) y
...
# mkdir mount
# mount -o loop initrd mount/
Copy modules to initrd:
<pre>
# cp -r ../livecd-root/lib/modules/2.6.18-ovz028stab035.1-smp/ mount/lib/modules/
# rm -rf mount/lib/modules/2.6.18-ovz028stab035.1-smp/build # we don't neet it on initrd image
</pre>
I also delete some not necessary kernel modules from initrd to free space.
They are stil on CD, so init sctipts will be able to load them later.
initrd image, that goes with Centos 4.4 LiveCD doesn't load cdrom kernel modules.
It works well for CentOS kernel, because cdrom support is built-in there.
# umount mount/
# gzip initrd
# /bin/cp initrd.gz ../ovz-livecd/boot/initrd.gz
# cd ..
</pre>
Also '''don't forget''' to change <tt>ramdisk_size</tt> to 102400 for all kernels including Centos 4.4 default!
And I suggest to remove <tt>quitequiet</tt> parameter, to see what happens: it will help greatly if some problem will happen.
=== Embellishment ===
console=ttyS0,115200 console=tty
</pre>
See more at [[remote console setup]].
== External Links ==
* [http://squashfs.sourceforge.net/ squashfs website]
* [http://www.filesystems.org/project-unionfs.html uninonfs official homepage]
[[Category: HOWTO]]
[[Category: Live CD]]
