Editing Creating OpenVZ LiveCD based on Centos 4.4

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This article is a step by step guide explaining how to add OpenVZ functionality to Centos 4.4 LiveCD.
 
This article is a step by step guide explaining how to add OpenVZ functionality to Centos 4.4 LiveCD.
 
As a result, you will have a LiveCD, that can boot in various OpenVZ kernels (rhel4-2.6.9, 2.6.18,
 
As a result, you will have a LiveCD, that can boot in various OpenVZ kernels (rhel4-2.6.9, 2.6.18,
−
rhel5-2.6.18, 2.6.20) and in original CentOS kernel also. After booting from the CD, you will be able  
+
rhel5-2.6.18, 2.6.20) and in original CentOS kernel also. After booting from CD, you will be able  
 
to create [[VE]]s, start them, enter them - i.e. perform [[Getting started with OpenVZ live CD | common OpenVZ activity]].
 
to create [[VE]]s, start them, enter them - i.e. perform [[Getting started with OpenVZ live CD | common OpenVZ activity]].
  
Line 11: Line 11:
 
automatize this process. ;)
 
automatize this process. ;)
  
−
Actually you need to accomplish the following general actions - everything else is only technical details:
+
Actually you need to know the following general actions: everything else is only technical details.
−
* Get a copy of CentOS 4.4 LiveCD image  
+
* Get a copy of CentOS 4.4 LiveCD iso image  
−
* Use <tt>unsquashfs</tt> tool to extract the contents of *.mo files, located on the image
+
* Add <tt>squashfs</tt> support to your kernel (TODO: use unsquashfs instead)
−
* Construct '''booted''' LiveCD root filesystem from extracted files
+
* Extract the contents of *.mo files from CD using <tt>squashfs</tt> and construct LiveCD root filesystem.
−
* Create OpenVZ kernel RPM-packages  with <tt>squashfs</tt> support
+
* Compile OpenVZ kernels with <tt>squashfs</tt> and <tt>unionfs</tt> support
−
* Compile <tt>unionfs</tt> kernel modules against OpenVZ kernels
+
* Get OpenVZ user-space tools: vzctl, vzquota, vzpkg, ... and some precreated templates.
−
* Get OpenVZ tools RPM-packages: vzctl, vzquota, vzpkg, etc. Get template metadatas and precreated templates
+
* Install OpenVZ kernel, tools and templates in LiveCD root filesystem
−
* Remove some RPM-packages from '''booted''' LiveCD root filesystem (conflicting with OpenVZ kernel packages and redundant packages - to free some disk space)
+
* Remove some packages from LiveCD root filesystem
−
* Install OpenVZ kernels, tools and templates in '''booted''' LiveCD root filesystem
 
−
* Using <tt>mksquashfs</tt> tool compress '''booted''' CD root filesystem
 
 
* Modify initrd image: add there kernel modules for OpenVZ kernels
 
* Modify initrd image: add there kernel modules for OpenVZ kernels
−
* Introduce small modifications to isolinux configuration file
+
* Introduce some small changes to isolinux configuration file
 
* Create new iso image
 
* Create new iso image
  
 
== Technical details ==
 
== Technical details ==
−
This part contains detailed description of LiveCD creation. I've removed the output of some
+
This part contents detailed description of LiveCD creation. I've removed the output of some
 
commands in order to simplify the reading.
 
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 ===
 
=== Creating booted LiveCD root filesystem ===
Line 47: Line 35:
 
</pre>
 
</pre>
  
−
First of all we need some raw material - CentOS 4.4 LiveCD image:
+
First of all we need some raw material - CentOS 4.4 LiveCD:
 
<pre>
 
<pre>
 
# wget http://mirror.nsc.liu.se/CentOS/4.4/isos/i386/CentOS-4.4-i386-LiveCD.iso
 
# wget http://mirror.nsc.liu.se/CentOS/4.4/isos/i386/CentOS-4.4-i386-LiveCD.iso
Line 67: Line 55:
  
 
You can see, that <tt>ovz-livecd/base/</tt> directory owns several *.mo files - images of squashfs filesystem,
 
You can see, that <tt>ovz-livecd/base/</tt> directory owns several *.mo files - images of squashfs filesystem,
−
and each image holds one directory of '''booted''' LiveCD root filesystem: <tt>bin</tt>, <tt>usr</tt> and so on:
+
and each image holds one directory of LiveCD root filesystem: <tt>bin</tt>, <tt>usr</tt> and so on:
 
<pre>
 
<pre>
 
# ls -1 ovz-livecd/base
 
# ls -1 ovz-livecd/base
Line 73: Line 61:
 
</pre>
 
</pre>
  
−
In order to decompress these images we need <tt>unsquashfs</tt> tool. <tt>squashfs</tt> source archive contains
+
In order to decompress these images we need <tt>squashfs</tt> tools. The source archive of <tt>squashfs</tt> contents
−
patches for various kernel versions (to be able to mount <tt>squashfs</tt>) and user-space tools for compressing usual filesytem into <tt>squashfs</tt> filesystem and for decompressing it back. Well, we don't need kernel patches right now (but we will need them later), we only want to install <tt>squashfs</tt> user-space tools.
+
patch for the kernel (to be able mount <tt>squashfs</tt>), and user-space tools for compressing/decomprassing usual filesytem
−
Here is '''an important''' note. We want, our LiveCD to be able to boot original Centos 4.4 kernel. This original kernel doesn't support
+
into squashfs filesystem. Well, we don't need the kernel patch right now (but we will need it later), we only want to install <tt>squashfs</tt> user-space tools:
−
<tt>squashfs</tt> of version <tt>3</tt>. Consequently we use <tt>sqashfs2.2-r2</tt> for <tt>mksquasfs</tt> tool, but for <tt>unsquashfs</tt> tool and later for compiling fresh OpenVZ kernels with <tt>squashfs</tt> support we use <tt>sqashfs3.2-r2</tt> sources/patches, because they are back compatible with <tt>sqashfs v2</tt>.
 
 
<pre>
 
<pre>
−
# wget http://belnet.dl.sourceforge.net/sourceforge/squashfs/squashfs2.2-r2.tar.gz
+
# wget wget http://switch.dl.sourceforge.net/sourceforge/squashfs/squashfs3.2-r2.tar.gz
−
# tar xzf squashfs2.2-r2.tar.gz
 
−
# cd squashfs2.2-r2/squashfs-tools/
 
−
# make
 
−
cc mksquashfs.o read_fs.o sort.o -lz -o mksquashfs
 
−
# cp mksquashfs /usr/bin/
 
−
 
 
−
# cd -
 
−
# wget http://belnet.dl.sourceforge.net/sourceforge/squashfs/squashfs3.2-r2.tar.gz
 
 
# tar xzf squashfs3.2-r2.tar.gz
 
# tar xzf squashfs3.2-r2.tar.gz
 
# cd squashfs3.2-r2/squashfs-tools/
 
# cd squashfs3.2-r2/squashfs-tools/
Line 92: Line 71:
 
cc mksquashfs.o read_fs.o sort.o -lz -lpthread -lm -o mksquashfs
 
cc mksquashfs.o read_fs.o sort.o -lz -lpthread -lm -o mksquashfs
 
cc unsquashfs.o -lz -o unsquashfs
 
cc unsquashfs.o -lz -o unsquashfs
 +
# cp mksquashfs /usr/bin/
 
# cp unsquashfs /usr/bin/
 
# cp unsquashfs /usr/bin/
−
# cd -
+
# cd ~/workbench
 
</pre>
 
</pre>
 
Well, having the intruments in hand, why not extract the images? Create a directory, called <tt>livecd-root</tt>,
 
Well, having the intruments in hand, why not extract the images? Create a directory, called <tt>livecd-root</tt>,
−
that will store the root filesystem of '''booted''' LiveCD. I.e. it will contain <tt>/bin</tt>, <tt>/sbin</tt>,
+
that will store the root filesystem for '''booted''' LiveCD. I.e. it will content <tt>/bin</tt>, <tt>/sbin</tt>,
 
<tt>/etc</tt> and other directories, which you will see after booting the LiveCD. Unfortunately <tt>unsquashfs</tt>
 
<tt>/etc</tt> and other directories, which you will see after booting the LiveCD. Unfortunately <tt>unsquashfs</tt>
 
tool is not very convenient, and I found only this way to use it:
 
tool is not very convenient, and I found only this way to use it:
Line 102: Line 82:
 
# mkdir livecd-root
 
# mkdir livecd-root
  
−
# for f in bin etc lib root sbin usr var; do \
+
# unsquashfs ovz-livecd/base/bin.mo
−
    unsquashfs ovz-livecd/base/$f.mo; \
+
# mv squashfs-root/bin/ livecd-root/
−
    mv squashfs-root/$f/ livecd-root; \
+
# rm -rf squashfs-root
−
    rm -rf squashfs-root; \
+
 
−
  done
+
# unsquashfs ovz-livecd/base/etc.mo
−
</pre>
+
# mv squashfs-root/etc/ livecd-root/
 +
# rm -rf squashfs-root
 +
 
 +
# unsquashfs ovz-livecd/base/lib.mo
 +
# mv squashfs-root/lib/ livecd-root/
 +
# rm -rf squashfs-root
 +
 
 +
# unsquashfs ovz-livecd/base/root.mo  
 +
# mv squashfs-root/root/ livecd-root/
 +
# rm -rf squashfs-root
 +
 
 +
# unsquashfs ovz-livecd/base/sbin.mo
 +
# mv squashfs-root/sbin/ livecd-root/
 +
# rm -rf squashfs-root
  
−
Be patient, this will take a few minutes.
+
# unsquashfs ovz-livecd/base/usr.mo    # this action takes some time, be patient ;)
 +
# mv squashfs-root/usr/ livecd-root/
 +
# rm -rf squashfs-root
  
−
Yet we have nearly complete root filesystem of '''booted''' LiveCD in <tt>livecd-root</tt> directory. However some things
+
# unsquashfs ovz-livecd/base/var.mo
−
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.
+
# mv squashfs-root/var/ livecd-root/
 +
# rm -rf squashfs-root
 +
</pre>
 +
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>
 
<pre>
−
# cd livecd-root
+
# mkdir root/dev
−
# mkdir dev
+
# cp -a /dev/* root/dev
−
# cp -a /dev/* dev/
+
# mkdir root/proc
−
# mkdir proc
+
# mount -t proc proc root/proc/
−
# mount -t proc proc proc/
+
# mkdir root/sys
−
# mkdir sys
+
# mount -t sysfs sysfs root/sys/
−
# mount -t sysfs sysfs sys/
+
# mkdir root/tmp
−
# mkdir tmp
+
# mkdir root/boot
−
# mkdir boot
 
−
# cd -
 
 
</pre>
 
</pre>
  
−
That's it. We have '''bootstrapped''' LiveCD root filesystem in <tt>livecd-root</tt> directory.
+
That's it. We have booted 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
 
Now we can <tt>chroot</tt> in this directory and install all needed packages. But what
 
packages do we need?
 
packages do we need?
−
* OpenVZ kernels
+
* OpenVZ kernel
 
* OpenVZ tools: vzctl, vzquota, vzpkg, vzrpm43, vzrpm44, vzyum
 
* OpenVZ tools: vzctl, vzquota, vzpkg, vzrpm43, vzrpm44, vzyum
 
* OpenVZ template metadatas: centos-4, fc-3, fc4 and fc-5
 
* OpenVZ template metadatas: centos-4, fc-3, fc4 and fc-5
 
* Some OpenVZ precreated templates
 
* Some OpenVZ precreated templates
−
* Some CentOS tool updates: sqlite package
+
* Some CentOS tools updates: sqlite package
 
Tools and templates related packages can be simply downloaded and installed.
 
Tools and templates related packages can be simply downloaded and installed.
 
But it is not so easy with kernel. Usual OpenVZ kernel won't work: it doesn't
 
But it is not so easy with kernel. Usual OpenVZ kernel won't work: it doesn't
−
support <tt>squashfs</tt>. The next chapter explains how to create RPM-package with
+
support <tt>squashfs</tt>. The next chapter explains how to create RPM package with
 
OpenVZ kernel, that supports <tt>squashfs</tt>
 
OpenVZ kernel, that supports <tt>squashfs</tt>
  
−
=== Building OpenVZ kernels ===
+
=== Building OpenVZ kernels and kernel modules ===
−
Let's consider, how to build <tt>2.6.18</tt> OpenVZ kernel RPM-package with <tt>squashfs</tt> support.
 
−
First  download and install OpenVZ source RPM:
 
−
<pre>
 
−
# wget http://download.openvz.org/kernel/branches/2.6.18/028stab035.1/kernel-2.6.18-ovz028stab035.1.src.rpm
 
−
# rpm -ivh kernel-2.6.18-ovz028stab035.1.src.rpm
 
−
</pre>
 
−
<tt>squashfs</tt> sources contain the patch against <tt>2.6.18</tt>. Let's copy this patch to RPM build directory:
 
−
<pre>
 
−
# cp squashfs3.2-r2/kernel-patches/linux-2.6.18/squashfs3.2-patch /usr/src/redhat/SOURCES/
 
−
</pre>
 
−
Now we need to modify the spec-file (<tt>/usr/src/redhat/SPECS/kernel-ovz.spec</tt>) in order to add <tt>squashfs</tt> patch to build process. Below are the changes you should introduce in diff format.
 
−
The meaning of changes is transparent: firstly, do not build UP, enterprise and debug kernels (our LiveCD will be
 
−
based on SMP kernel) and secondly, apply <tt>squashfs</tt> patch before compilation.
 
−
<pre>
 
−
--- kernel-ovz.spec.orig        2007-06-09 11:40:15.000000000 +0400
 
−
+++ kernel-ovz.spec    2007-06-28 17:42:41.000000000 +0400
 
−
@@ -5,13 +5,13 @@ Summary: The Linux kernel (the core of t
 
  
−
# normal/debug/debuginfo
 
−
%define buildnormal 1
 
−
-%define builddebug 1
 
−
+%define builddebug 0
 
−
%define builddebuginfo 0
 
  
−
# kernels we want to build
+
To be continued...
−
-%define buildup 1
 
−
+%define buildup 0
 
−
%define buildsmp 1
 
−
-%define buildenterprise 1
 
−
+%define buildenterprise 0
 
−
%define buildentnosplit 0
 
  
−
# versions
 
−
@@ -161,6 +161,9 @@ Patch2104: linux-2.6.18-drbd-0.7.22-0.8.
 
−
Patch2105: linux-2.6.18-drbd-8.0.0-8.0.2.patch
 
−
Patch2106: linux-2.6.18-drbd-8.0.2-8.0.3.patch
 
  
−
+# squashfs3.2-patch
 
−
+Patch2107: squashfs3.2-patch
 
−
+
 
−
# ----------------------------------------------------------------------------
 
  
−
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
 
−
@@ -318,6 +321,8 @@ cd linux-%{kversion}
 
−
%patch2105 -p1
 
−
%patch2106 -p1
 
  
−
+%patch2107 -p1
+
=== Obrezki ===
−
+
+
TODO
−
# ----------------------------------------------------------------------------
+
rpms/
 +
rpms/kernel
 +
rpms/tools
 +
rpms/update
  
−
mkdir configs
+
Uninstall <tt>lsctp-tools</tt> package, because these tools they need kernel version prior to 2.6.10:
−
</pre>
 
−
We need one more tiny hack in order RPM-build process to walk smoothly.
 
−
There are config files for various OpenVZ kernel flavours
 
−
in <tt>/usr/src/redhat/SOURCES</tt> directory:
 
 
<pre>
 
<pre>
−
# ls /usr/src/redhat/SOURCES/*.config.ovz
+
rpm -e lksctp-tools-1.0.2-6.4E.1.i386
−
/usr/src/redhat/SOURCES/kernel-2.6.18-i686.config.ovz            /usr/src/redhat/SOURCES/kernel-2.6.18-ppc64.config.ovz
 
−
/usr/src/redhat/SOURCES/kernel-2.6.18-i686-enterprise.config.ovz  /usr/src/redhat/SOURCES/kernel-2.6.18-x86_64.config.ovz
 
−
/usr/src/redhat/SOURCES/kernel-2.6.18-i686-smp.config.ovz        /usr/src/redhat/SOURCES/kernel-2.6.18-x86_64-smp.config.ovz
 
−
/usr/src/redhat/SOURCES/kernel-2.6.18-ia64.config.ovz
 
 
</pre>
 
</pre>
−
'''All''' these files should contain information about <tt>squashfs</tt>.
+
Uninstall kernel-module-xfs package, because these modules are compiled against original
−
In fact, only two additional lines are necessary:
 
 
<pre>
 
<pre>
−
CONFIG_SQUASHFS=m
+
rpm -e kernel-module-xfs-2.6.9-42.livecd.c4-0.1-3.i686
−
CONFIG_SQUASHFS_EMBEDDED=n
 
 
</pre>
 
</pre>
−
I did it with the following command:
 
−
<pre>
 
−
# cd /usr/src/redhat/SOURCES/
 
−
# echo "CONFIG_SQUASHFS=m
 
−
> CONFIG_SQUASHFS_EMBEDDED=n" | tee -a *.config.ovz
 
−
CONFIG_SQUASHFS=m
 
−
CONFIG_SQUASHFS_EMBEDDED=n
 
−
</pre>
 
−
After all efforts, building the RPM-package is very easy:
 
−
<pre>
 
−
# cd /usr/src/redhat/SPECS/
 
−
# rpmbuild --target=i686 -ba kernel-ovz.spec
 
−
</pre>
 
−
If everything goes smoothly, in several tens of minutes depending on the power of your node you willl have OpenVZ kernel RPM-package with <tt>squashfs</tt> support. Let's copy it to our local directory <tt>to_booted_livecd/kernels/</tt>:
 
−
<pre>
 
−
# cd ~/workbench/
 
−
# ls /usr/src/redhat/RPMS/i686/
 
−
kernel-smp-2.6.18-ovz028stab035.1.i686.rpm
 
−
# mkdir -p to_booted_livecd/kernels
 
−
# cp /usr/src/redhat/RPMS/i686/kernel-smp-2.6.18-ovz028stab035.1.i686.rpm to_booted_livecd/kernels/
 
−
</pre>
 
−
OpenVZ LiveCD supports several kernels. So, the actions mentioned above should be accomplished to all kernels,
 
−
that you need on LiveCD. In this article I skip the description of building RPMS for all kernels. All description
 
−
below are based on <tt>028stab035</tt> kernel, that has been just build above. But some important differences in building
 
−
kernel of version other then 2.6.18 one is summarized below.
 
−
==== Peculiarities of building 2.6.9-rhel4 ====
 
−
* You should also include this 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 ====
+
cd /tmp/rpms/kernel
−
* Note, <tt>squashfs</tt> patch is already there, but you should use <tt>3.2</tt>! :)
+
rpm -ivh kernel-smp-2.6.18-ovz028stab033.1.i686.rpm
−
* While building <tt>unionfs</tt> some small fixes: <tt>i_blksize</tt> field is missing in <tt>inode</tt> structure, <tt>ino_t</tt> should be changed to <tt>u64</tt> in some functions.
+
rpm -e kernel-2.6.9-42.livecd.c4
  
−
==== Peculiarities of building 2.6.20 ====
+
cd /tmp/rpms/updates
−
* Only <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
+
rpm -Uvh sqlite-3.3.6-2.i386.rpm
−
* <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>
−
In most present-day LiveCDs <tt>unionfs</tt> filesystem is used. This filesystem "can appear to merge the contents of several directories, while keeping their physical content separate". For example, after the command
+
# rpm -ivh vz*
−
<pre>
 
−
# mount -t unionfs -o dirs=/tmp/changes=rw:/cdrom=ro unionfs /union
 
−
</pre>
 
−
you will see merged contents of <tt>/cdrom</tt> and <tt>/tmp/changes</tt> directories in <tt>/union</tt> directory.
 
−
At that, <tt>cdrom</tt> will be read-only. I.e. if you will write to some file in <tt>/union</tt> directory,
 
−
that resides in <tt>/cdrom</tt> in fact, this modified file will be automatically moved to <tt>/tmp/changes</tt>.
 
−
Such useful property is logically used in LiveCDs: <tt>unionfs</tt> merges cdrom contents (that is read-only)
 
−
and temporary in-memory filesystem.
 
−
In order to add support of <tt>unionfs</tt> filesystem to OpenVZ kernel we need to compile <tt>unionfs</tt> kernel
 
−
module against used kernel. Download the sources of unionfs:
 
−
<pre>
 
−
# wget ftp://ftp.filesystems.org/pub/unionfs/unionfs-1.x/unionfs-1.4.tar.gz
 
−
# tar xzf unionfs-1.4.tar.gz
 
−
</pre>
 
−
In previous chapter we have created an RPM-package with OpenVZ kernel. We should install it: because
 
−
this packages contents kernel headers, required for building kernel modules.
 
−
<pre>
 
−
# rpm -ivh to_booted_livecd/kernels/kernel-smp-2.6.18-ovz028stab035.1.i686.rpm
 
 
Preparing...                ########################################### [100%]
 
Preparing...                ########################################### [100%]
−
   1:kernel-smp            ########################################### [100%]
+
   1:vzrpm44                ########################################### [ 8%]
−
</pre>
+
  2:vzrpm44-python        ########################################### [ 15%]
−
Now compile <tt>unionfs</tt>:
+
  3:vzrpm43-python         ########################################### [ 23%]
−
<pre>
+
  4:vzrpm43                ########################################### [ 31%]
−
# cd unionfs-1.4
+
  5:vzyum                  ########################################### [ 38%]
−
# echo 'LINUXSRC=/lib/modules/2.6.18-ovz028stab035.1-smp/build/
+
  6:vzquota                ########################################### [ 46%]
−
> TOPINC=-I$(LINUXSRC)/include
+
  7:vzctl-lib              ########################################### [ 54%]
−
> MODDIR=/lib/modules/2.6.18-ovz028stab035.1-smp/' > fistdev.mk
+
  8:vzctl                  ########################################### [ 62%]
−
# make
+
  9:vzpkg                  ########################################### [ 69%]
−
# ls unionfs.ko
+
   10:vztmpl-centos-4       ########################################### [ 77%]
−
unionfs.ko
+
   11:vztmpl-fedora-core-3   ########################################### [ 85%]
−
# cd ..
+
   12:vztmpl-fedora-core-4   ########################################### [ 92%]
−
</pre>
+
   13:vztmpl-fedora-core-5   ########################################### [100%]
−
Later we will place <tt>unionfs.ko</tt> to appropriate place in '''booted''' LiveCD filesystem.
+
</tt>
−
At the moment copy it to local <tt>to_booted_livecd/unionfs-modules/2.6.18/</tt> directory:
 
−
<pre>
 
−
# mkdir -p to_booted_livecd/unionfs-modules/2.6.18/
 
−
# cp unionfs-1.4/unionfs.ko to_booted_livecd/unionfs-modules/2.6.18/
 
−
</pre>
 
−
I repeat once again: if you want to use several kernels on LiveCD - the operation above should
 
−
be repeated for each wishful kernel.
 
−
 
 
−
=== OpenVZ tools and templates. CentOS updates ===
 
−
We have now the kernel RPM-package. But we also need OpenVZ tools RPM-packages.
 
−
It is much easier with them: just download these packages from http://openvz.org:
 
−
<pre>
 
−
# mkdir to_booted_livecd/tools
 
−
# cd to_booted_livecd/tools/
 
−
 
 
−
# wget http://download.openvz.org/utils/vzctl/3.0.16/vzctl-3.0.16-1.i386.rpm
 
−
# wget http://download.openvz.org/utils/vzctl/3.0.16/vzctl-lib-3.0.16-1.i386.rpm
 
−
# wget http://download.openvz.org/utils/vzquota/3.0.9/vzquota-3.0.9-1.i386.rpm
 
−
# wget http://download.openvz.org/template/utils/vzpkg/2.7.0-18/vzpkg-2.7.0-18.noarch.rpm
 
−
# wget http://download.openvz.org/template/utils/vzrpm43/current/vzrpm43-4.3.3-7_nonptl.6.i386.rpm
 
−
# wget http://download.openvz.org/template/utils/vzrpm43/current/vzrpm43-python-4.3.3-7_nonptl.6.i386.rpm
 
−
# wget http://download.openvz.org/template/utils/vzrpm44/current/vzrpm44-4.4.1-22.5.i386.rpm
 
−
# wget http://download.openvz.org/template/utils/vzrpm44/current/vzrpm44-python-4.4.1-22.5.i386.rpm
 
−
# wget http://download.openvz.org/template/utils/vzyum/current/vzyum-2.4.0-11.noarch.rpm
 
−
 
 
−
# mkdir ../template-metadatas
 
−
# cd ../template-metadatas
 
−
 
 
−
# wget http://download.openvz.org/template/metadata/centos-4/vztmpl-centos-4-2.0-2.i386.rpm
 
−
# wget http://download.openvz.org/template/metadata/fedora-core-3/vztmpl-fedora-core-3-2.0-2.i386.rpm
 
−
# wget http://download.openvz.org/template/metadata/fedora-core-4/vztmpl-fedora-core-4-2.0-2.i386.rpm
 
−
# wget http://download.openvz.org/template/metadata/fedora-core-5/vztmpl-fedora-core-5-2.0-2.i386.rpm
 
−
 
 
−
# mkdir ../precreated
 
−
# cd ../precreated
 
−
 
 
−
# wget http://download.openvz.org/template/precreated/centos-4-i386-minimal.tar.gz
 
−
# wget http://download.openvz.org/template/precreated/debian-3.1-i386-minimal.tar.gz
 
−
# wget http://download.openvz.org/template/precreated/fedora-core-5-i386-minimal.tar.gz
 
−
 
 
−
# cd ~/workbench/
 
−
</pre>
 
−
As you understand, you can add other precreated templates to LiveCD. The main thing here is that usual CD is
 
−
not rubber and precreated templates are rather big! ;)
 
−
 
 
−
Centos 4.4 LiveCD has a serios problem: <tt>sqlite</tt> package is broken and consequently
 
−
<tt>yum</tt> doesn't work. In order to fix this problem we need updated <tt>sqlite</tt> package:
 
−
<pre>
 
−
# mkdir to_booted_livecd/updates
 
−
# cd to_booted_livecd/updates
 
−
# wget http://centos.arcticnetwork.ca/4.5/os/i386/CentOS/RPMS/sqlite-3.3.6-2.i386.rpm
 
−
# cd ~/workbench/
 
−
</pre>
 
−
 
 
−
=== Install all these finally ===
 
−
We have all components that will be on '''booted''' LiveCD ready. Let's install them
 
−
in <tt>chrooted</tt> environment. But before uninstall <tt>lsctp-tools</tt> package,
 
−
because these tools need kernel version prior to 2.6.10. Then update <tt>sqlite</tt>
 
−
package. Also we need to remove some other packages in order to free some disk space:
 
−
I've removed <tt>openoffice.org</tt>, <tt>gimp</tt>, <tt>dia</tt>, <tt>gnome-games</tt>,
 
−
<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
 
−
 
 
−
# rpm -e openoffice.org-libs openoffice.org
 
−
# rpm -e gimp-data-extras xsane-gimp gimp-print-plugin gimp-print-utils
 
−
# rpm -e gimp gimp-print gimp-help gimp-gap
 
−
# rpm -e dia
 
−
# rpm -e planner
 
−
# rpm -e gnome-games
 
−
# rpm -e tetex-latex jadetex xmltex passivetex tetex tetex-afm \
 
−
tetex-dvips tetex-fonts tetex-xdvi
 
−
# rpm -e k3b
 
−
# rpm -e foomatic Omni Omni-foomatic system-config-printer \
 
−
system-config-printer-gui hal-cups-utils desktop-printing
 
−
 
 
−
# cd /tmp/to_booted_livecd/
 
−
 
 
−
# rpm -Uvh updates/sqlite-3.3.6-2.i386.rpm
 
−
 
 
−
# rpm -ivh kernels/kernel-smp-2.6.18-ovz028stab035.1.i686.rpm
 
−
# rpm -ivh tools/*.rpm
 
−
# rpm -ivh template-metadatas/*.rpm
 
−
</pre>
 
−
 
 
−
Copy precreated templates to appropriate place:
 
−
<pre>
 
−
# cp  precreated/* /vz/template/cache/
 
−
</pre>
 
−
Add <tt>unionfs.ko</tt> to other kernel modules and run <tt>depmod</tt>:
 
−
<pre>
 
−
# mkdir /lib/modules/2.6.18-ovz028stab035.1-smp/kernel/fs/unionfs
 
−
# cp unionfs-modules/2.6.18/unionfs.ko /lib/modules/2.6.18-ovz028stab035.1-smp/kernel/fs/unionfs/
 
−
# depmod 2.6.18-ovz028stab035.1-smp
 
−
# exit
 
−
exit
 
−
</pre>
 
−
While being in chrooted environment bash history was written to <tt>~/.bash_history</tt> file.
 
−
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
 
−
chekpointing isn't supported on <tt>unionfs</tt> filesystem ([http://bugzilla.openvz.org/show_bug.cgi?id=606  Bug #606]).
 
−
But we want of course checkpoiting to work on LiveCD. If we mount <tt>tmpfs</tt> on <tt>/vz/private/</tt> on '''booted''' LiveCD,
 
−
then all newly created VEs reside on <tt>tmpfs</tt> and checkpointing works. Moreover we do not introduce any additional memory usage,
 
−
because even without <tt>tmpfs</tt> all VEs reside in RAM (they contain new/updated files for <tt>unionfs</tt>).
 
−
 
 
−
Create <tt>/vz/private</tt> directory, later, while modifying initrd image we will add the line that will mount <tt>tmpfs</tt>
 
−
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]).
 
−
We're working on this problem, but for now '''switching the disk quota off''' in <tt>/etc/vz/vz.conf</tt>: <tt>DISK_QUOTA=no</tt>.
 
−
But when disk quota is off <tt>vzmigrate</tt> fails! ;) This is the [http://bugzilla.openvz.org/show_bug.cgi?id=558  Bug #512].
 
−
So, don't forget to apply the patch attached to this bug report to <tt>vzmigrate</tt>.
 
−
 
 
−
'''Booted''' LiveCD filesystem is ready, congratulations!
 
−
 
 
−
=== Compressing '''booted''' LiveCD filesystem ===
 
−
Since <tt>mksquashfs</tt> tool is already installed we can simply use it to create
 
−
<tt>*.mo</tt> files:  
 
−
<pre>
 
−
# rm -f ovz-livecd/base/*.mo
 
−
# for f in bin etc lib root sbin usr var vz; do \
 
−
    mksquashfs livecd-root/$f ovz-livecd/base/$f.mo -keep-as-directory; \
 
−
   done
 
−
</pre>
 
−
 
 
−
=== Vmlinux, initrd and isolinux.cfg ===
 
−
The next step is to force <tt>isolinux</tt> (cdrom boot loader) to boot OpenVZ kernel.
 
−
First, copy kernel image to OpenVZ CD. It is important to give '''short name''' (not greater
 
−
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
 
−
and apply small patches to <tt>liblinuxlive</tt> file. Initrd image that goes with Centos 4.4 is
 
−
of size 40Mb. OpenVZ LiveCD will contain several kernels, so initrd should have several sets of
 
−
kernel modules (for each kernel) and 40Mb isn't enough in this case. I created an initrd of size 100Mb.
 
−
Don't forget to update <tt>ramdisk_size</tt> in <tt>isolinux.cfg</tt> file later!
 
−
 
 
−
Creating "big" initrd with original content:
 
−
<pre>
 
−
# mkdir initrd.d
 
−
# cp ovz-livecd/boot/initrd.gz initrd.d/initrd-old.gz
 
−
# cd initrd.d/
 
−
# mkdir mount-old
 
−
# gunzip initrd-old.gz
 
−
# 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/
 
−
# cp -a mount-old/* mount/
 
−
# umount mount-old/
 
−
# rm -rf mount-old initrd-old
 
−
</pre>
 
−
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.
 
−
But OpenVZ kernel supports cdrom (usual ide cdrom) via kernel module.
 
−
Consequetnly we need to apply the following patch to <tt>liblinuxlive</tt> file:
 
−
<pre>
 
−
--- liblinuxlive.orig   2006-08-19 08:53:11.000000000 +0400
 
−
+++ liblinuxlive        2007-07-02 17:50:34.000000000 +0400
 
−
@@ -337,6 +337,9 @@ modprobe_essential_modules()
 
−
{
 
−
    echolog "starting loop device support"
 
−
    modprobe_module loop max_loop=32
 
−
+   echolog "starting cdrom support"
 
−
+   modprobe_module cdrom
 
−
+  modprobe_module ide-cd
 
−
    echolog "starting cdrom filesystem support"
 
−
    modprobe_module isofs
 
−
    echolog "starting squashfs support"
 
−
</pre>
 
−
As mentioned earlier we want to mount <tt>tmpfs</tt> on /vz/private automatically. Just apply this patch to
 
−
<tt>liblinuxlive</tt> file:
 
−
<pre>
 
−
--- liblinuxlive.orig-fstab    2007-07-02 17:50:34.000000000 +0400
 
−
+++ mount/liblinuxlive  2007-07-03 12:33:30.000000000 +0400
 
−
@@ -414,6 +414,7 @@ activate_fstab()
 
−
    echo "tmpfs            /                tmpfs      defaults        0   0" >$FSTAB
 
−
    echo "devpts          /dev/pts        devpts      gid=5,mode=620  0  0" >>$FSTAB
 
−
    echo "proc            /proc            proc        defaults        0  0" >>$FSTAB
 
−
+  echo "tmpfs            /vz/private      tmpfs      defaults        0  0" >>$FSTAB
 
−
 
 
−
    # now done by fstab-sync
 
−
    # list_cdrom_devices | while read DEVICE; do
 
−
</pre>
 
−
Finishing actions with initrd:
 
−
<pre>
 
−
# sync
 
−
# umount mount/
 
−
# gzip initrd
 
−
# cp initrd.gz ../ovz-livecd/boot/initrd.gz
 
−
# cd ..
 
−
</pre>
 
−
Now we should modify <tt>ovz-livecd/isolinux.cfg</tt> file, that controls <tt>isolinux</tt> boot loader.
 
−
We inform boot loader, that new kernel was added by introducing the following changes (in diff format):
 
−
<pre>
 
−
--- ovz-livecd/isolinux.cfg.orig   2006-08-19 08:53:09.000000000 +0400
 
−
+++ ovz-livecd/isolinux.cfg    2007-07-02 19:10:51.000000000 +0400
 
−
@@ -1,5 +1,5 @@
 
−
display boot/splash.cfg
 
−
-default linux
 
−
+default ovz18
 
−
prompt 1
 
−
timeout 300
 
−
F1 boot/help1.txt
 
−
@@ -11,5 +11,9 @@ label linux
 
−
kernel boot/vmlinuz
 
−
append max_loop=32 vga=791 initrd=boot/initrd.gz init=linuxrc load_ramdisk=1 prompt_ramdisk=0 ramdisk_size=40000 root=/dev/ram0 rw rhgb quiet
 
−
 
 
−
+label ovz18
 
−
+kernel boot/ovz18
 
−
+append max_loop=32 vga=791 initrd=boot/initrd.gz init=linuxrc load_ramdisk=1 prompt_ramdisk=0 ramdisk_size=102400 root=/dev/ram0 rw rhgb
 
−
+
 
−
label memtest
 
−
kernel boot/memtest
 
−
 
 
−
</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>quiet</tt> parameter, to see what happens: it will help greatly if some problem will happen.
 
−
 
 
−
=== Embellishment ===
 
−
If you want to release LiveCD to other people some "embelishments" should be added.
 
−
 
 
−
First, edit <tt>splash.cfg</tt>, <tt>help1.txt</tt>, <tt>help2.txt</tt> and <tt>help3.txt</tt>
 
−
files (that are in <tt>~/workbench/ovz-livecd/boot/help</tt> directory) to contain appropriate information.
 
−
These messages appear on the LiveCD initial boot: they help to choose kernel and kernel options.
 
−
 
 
−
Also, you can note, that CentOS logo appears at this moment. This logo resides in <tt>ovz-livecd/boot/splash.lss</tt>
 
−
file. I added OpenVZ logo there. The following tools will help you: <tt>lss16toppm</tt>, <tt>ppmtolss16</tt> and
 
−
of course <tt>gimp</tt> :)
 
−
 
 
−
One more thing we change is default desktop background. It resides in <tt>usr/share/backgrounds/images/default.png</tt>.
 
−
I added OpenVZ logo there.
 
−
 
 
−
=== Creating ISO ===
 
−
Centos 4.4 LiveCD creators were very gentle and have placed <tt>make_iso.sh</tt> script on CD.
 
−
Using this script, it is very easy to create iso:
 
−
<pre>
 
−
# cd ovz-livecd
 
−
# ./make_iso.sh ../CentOS-4.4-i386-OpenVZ-LiveCD.iso
 
−
</pre>
 
−
 
 
−
== Debugging LiveCD ==
 
−
If you have trouble with created OpenVZ LiveCD, boot the kernel with
 
−
<pre>
 
−
vga=0 debug
 
−
</pre>
 
−
command line options. It will help you to diagnose the problem more precisely.
 
−
Also it can be useful to redirect kernel output to serial console:
 
−
<pre>
 
−
console=ttyS0,115200 console=tty
 
−
</pre>
 
−
 
 
−
See more at [[remote console setup]].
 
  
 
== External Links ==
 
== External Links ==
Line 567: Line 191:
 
* [http://squashfs.sourceforge.net/ squashfs website]
 
* [http://squashfs.sourceforge.net/ squashfs website]
 
* [http://www.filesystems.org/project-unionfs.html uninonfs official homepage]
 
* [http://www.filesystems.org/project-unionfs.html uninonfs official homepage]
−
 
−
[[Category: HOWTO]]
 
−
[[Category: Live CD]]
 

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