Philippe : /* Installing */

2008-08-02T20:09:21Z

‎Installing

Philippe : /* Foreword */

2008-01-08T20:43:34Z

‎Foreword

Philippe le 2 janvier 2008 à 15:43

2008-01-02T15:43:12Z

Nouvelle page

If, for whatever reason you want to install a [http://www.debian.org Debian Etch]''DomU'' using a [http://www.debian.org Debian Etch] / [http://www.xensource.com Xen 3.1.0] ''Dom0'' using the '''Debian Installer''' instead of the [http://xen-tools.org/software/xen-tools/ xen-tools], this article may help you...

= Foreword =
This articles describes how to install a [http://www.debian.org Debian Etch]''DomU'' using the ''Debian Installer''

We have here a [http://www.debian.org Debian Etch]''Dom0'', but this could easily be extended to any ''Dom0'', as we do not use the usual [http://xen-tools.org/software/xen-tools/ xen-tools]

= About the installer =
The [http://www.debian.org Debian] installer does not know anything about Xen...

But the ''NetInstall'' CD Image just contains a kernel and an initrd, which in turn contains all the install procedure.

So basically we will run a standard ''xenified'' kernel with the netinstall initrd

{{Box Note| We are doing a 64-Bits install here, the kernel used is the vanilla Xen kernel, and the initrd is extracted from the ''mini.iso'' installer image}}

= Disk allocation =
We use a logical volume to allocate disk space for the virtual machine:
{{Box Code|shell| lvcreate -L 10240 -n sixty-four vgXen }}
It will be used as Disk Image (''xvd'') by the virtual machine. This gives more flexibility to the guest than individual partitions (''hd''), and makes the boot process easier (see below).

= Xen DomU Configuration file =
This is the minimal configuration file that we will use for this installation:
{{Box File|/etc/xen/sixty-four.cfg|2=<nowiki></nowiki>
# -*- mode: python; -*-
#============================================================================
# Python configuration setup for 'xm create'.
# This script sets the parameters used when a domain is created using 'xm create'.
# You use a separate script for each domain you want to create, or
# you can set the parameters for the domain on the xm command line.
#============================================================================

#----------------------------------------------------------------------------
# Kernel image file.
bootloader="/usr/bin/pygrub"

# Initial memory allocation (in megabytes) for the new domain.
memory = 512

# A name for your domain. All domains must have different names.
name = "sixty-four"

#----------------------------------------------------------------------------
# Define network interfaces.
vif = [ 'ip=xxx.xxx.xxx.xxx,mac=yy:yy:yy:yy:yy:yy,bridge=xenloc0' ]

#----------------------------------------------------------------------------
# Define the disk devices you want the domain to have access to, and
# what you want them accessible as.
# Each disk entry is of the form phy:UNAME,DEV,MODE
# where UNAME is the device, DEV is the device name the domain will see,
# and MODE is r for read-only, w for read-write.
disk = [ 'phy:/dev/vgDomU/sixty-four,xvda,w' ]

#----------------------------------------------------------------------------
# Define frame buffer device.
# vfb = ["type=vnc,vncunused=1"]
keymap = 'fr-be'

#----------------------------------------------------------------------------
# Configure the behaviour when a domain exits. There are three 'reasons'
# for a domain to stop: poweroff, reboot, and crash.
on_poweroff = 'destroy'
on_reboot = 'restart'
on_crash = 'restart'

#============================================================================
}}

The interresting aspect of using {{Command|pygrub}} as ''bootloader'' instead of specifying a kernel and a ramdisk is that the linux kernel will be taken from the ''DomU'' virtual machine and not from the ''Dom0'' host. Obviously we will have to override that during the installation.

= Installation =

== Booting ==

To avoid the text-mode-in-console, we use the Xen Virtual Frame Buffre (''vfb''), so we need to tell the kernel:
{{Box Code|shell|2=<nowiki></nowiki>
LinuxRC="xencons=ttyS0 video=xenfb"
}}

We also override the ''bootloader'' directive and specify the installation kernel.
<br />We also need to ask for a ''destroy'' at reboot time, otherwise the virtual machine would re-enter the installation procedure when done!
{{Box Code|shell|2=<nowiki></nowiki>
XmCreate="bootloader= \
kernel=/boot/debian-etch-amd64/vmlinuz-2.6.18-xen \
ramdisk=/boot/debian-etch-amd64/initrd-netinst.gz \
on_reboot=destroy"
}}

We start the installation with the following incantation:
{{Box Code|shell|2=<nowiki></nowiki>
xm create /etc/xen/sixty-four.cfg \
${XmCreate} \
vfb='type=vnc,vncunused=1' \
extra="${LinuxRC}"
}}

We start {{Command|xvncviewer}} to access the install console -- e.g.:
{{Box Code|shell|2=<nowiki></nowiki>
xvncviewer -via <Dom0> :1
}}

== Installing ==
We are now in the (text-mode / graphical) installer.
<br />We will be asked for the language, timezone...

The machine will find the packages and proceed with the installation just like on a bare metal system.

{{Boite Attention|There are a couple of things we need to know:
# The vanilla Xen kernel does not have ''ext3'' built-in, so we need to create ''ext2'' filesystems
# Debian Grub does not like ''xvd'' as device name, so you will not be able to install Grub
# No Xen kernel is installed by default
}}

== Reboot ==
At the end of the installation, the system reboots and you are back at the command prompt of your ''Dom0'' host.

Since we specified the ''on_reboot=destroy'' parameter, we need to restart the virtual machine, using this time only the parameters from the configuration file:
{{Box Code|shell| xm create /etc/xen/sixty-four.cfg *** TBD*** }}

After the {{Command|pygrub}} boot screen the system will start, ask a couple of post-install questions and we are done!

= Post Install =

ToDo

@@ Ligne 109: / Ligne 109: @@
 {{Boite Attention|There are a couple of things we need to know:
 # The vanilla Xen kernel does not have ''ext3'' built-in, so we need to create ''ext2'' filesystems
-# Debian Grub does not like ''xvd'' as device name, so you will not be able to install Grub
+# Etch Debian Grub does not like ''xvd'' as device name, so you will not be able to install Grub without recompiling the package.<br />There is no issue with Debian Lenny
-# No Xen kernel is installed by default
+# No Xen kernel is installed by default, so at the end of the installation, ask a shell, chroot the installed system and install the xen kernel.
 }}

@@ Ligne 2: / Ligne 2: @@
 = Foreword =
-This articles describes how to install a [http://www.debian.org Debian Etch]''DomU'' using the ''Debian Installer''
+This articles describes how to install a [http://www.debian.org Debian Etch] ''DomU'' using the ''Debian Installer''
 We have here a [http://www.debian.org Debian Etch]''Dom0'', but this could easily be extended to any ''Dom0'', as we do not use the usual [http://xen-tools.org/software/xen-tools/ xen-tools]

Xen Debian Installer - Historique des versions

Philippe : /* Installing */

Philippe : /* Foreword */

Philippe le 2 janvier 2008 à 15:43