The Perfect Xen Setup For Debian And Ubuntu - Page 3

3.2 Installing From The Sources

Run the following commands:

apt-get remove exim4 exim4-base lpr nfs-common portmap pidentd pcmcia-cs pppoe pppoeconf ppp pppconfig
apt-get install iproute bridge-utils python-twisted gcc-3.3 binutils make libcurl3-dev zlib1g-dev python-dev transfig bzip2 screen ssh debootstrap libcurl3-dev libncurses5-dev (1 line!)
cd ~
mkdir xen
cd xen
mkdir archive
cd archive

3.2.1 Install Xen

Now execute these commands:

wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.11.12.tar.bz2
wget http://www.cl.cam.ac.uk/Research/SRG/netos/xen/downloads/xen-2.0.7-src.tgz
cd ..

tar -xvzf archive/xen-2.0.7-src.tgz
tar -xvjf archive/linux-2.6.11.12.tar.bz2

cd xen-2.0
make world

make install
sh ./install.sh

Now Xen is installed. In order to start the Xen services at boot time, do the following:

update-rc.d xend defaults 20 21
update-rc.d xendomains defaults 21 20

3.2.2 Compile A New dom0 Kernel

Next we compile a new dom0 kernel with Xen-, iptables-, quota-, and dummy support. The kernel will be installed to ~/xen/install so that we can save it for other machines. From ~/xen/install we will install it to the real locations. Xen works with kernel 2.6.11, so I take the latest 2.6.11 kernel (2.6.11.12) instead of newer kernels, e.g. 2.6.14.

cd ..
mv /lib/tls /lib/tls.disabled
cp -al linux-2.6.11.12 linux-2.6.11.12-xen0
cd xen-2.0/linux-2.6.11-xen-sparse/
./mkbuildtree ../../linux-2.6.11.12-xen0/
cd ../..
echo "-xen0" > linux-2.6.11.12-xen0/localversion-xen
diff -Naur linux-2.6.11.12 linux-2.6.11.12-xen0 > archive/linux-2.6.11.12-xen0.patch

cd linux-2.6.11.12
patch -p1 < ../archive/linux-2.6.11.12-xen0.patch
cd ../
mkdir install
cd linux-2.6.11.12-xen0
cp arch/xen/configs/xen0_defconfig .config
ARCH=xen; INSTALL_PATH=../install; INSTALL_MOD_PATH=../install
export ARCH INSTALL_PATH INSTALL_MOD_PATH
make oldconfig
make menuconfig

In the kernel configuration menu that shows up we have to enable quota, iptables and the dummy network driver as modules. This is where you enable these modules:

File systems --> [*] Quota support
<M> Old quota format support
<M> Quota format v2 support

Device Drivers ---> Networking support ---> <M> Dummy net driver support

Device Drivers ---> Networking support ---> Networking options ---> [*] Network packet filtering (replaces ipchains) ---> IP: Netfilter Configuration ---> <M> IP tables support (required for filtering/masq/NAT)

[*] means: build into the kernel statically.
<M> means: build as a kernel module.

Now we install the kernel to ~/xen/install:

make modules
make modules_install
make install

Finally, we copy the kernel to the "real" locations:

cd ../install/
cp boot/* /boot
cp -r lib/modules/2.6.11.12-xen0/ /lib/modules
cp -r usr/include/xen /usr/include

(If you are interested, this is my dom0 kernel configuration.)

3.2.3 Configure The Bootloader And Reboot

Next we add our new kernel to Grub, our bootloader. Edit /boot/grub/menu.lst, and before the line ### BEGIN AUTOMAGIC KERNELS LIST add the following stanza:

title        Xen 2.0.7 / XenLinux 2.6.11.12-xen0
root        (hd0,0)
kernel        /xen.gz dom0_mem=65536
module        /vmlinuz-2.6.11.12-xen0 root=/dev/hda6 ro console=tty0

Make sure that /dev/hda6 is your / partition. Keep in mind what I said about Grub and partitioning in chapter 1!

Now reboot the system:

shutdown -r now

At the boot prompt, Grub should now list Xen 2.0.7 / XenLinux 2.6.11.12-xen0 as the first kernel and boot it automatically. If your system comes up without problems, then everything is fine!

3.2.4 Compile A New domU Kernel

Now we compile a new domU kernel for our virtual machines. Again, we install the kernel in ~/xen/install and copy it to the real location afterwards:

cd ~/xen
cd linux-2.6.11.12
make clean
cd ../
cp -al linux-2.6.11.12 linux-2.6.11.12-xenU
cd xen-2.0/linux-2.6.11-xen-sparse/
./mkbuildtree ../../linux-2.6.11.12-xenU/
cd ../..
echo "-xenU" > linux-2.6.11.12-xenU/localversion-xen
diff -Naur linux-2.6.11.12 linux-2.6.11.12-xenU > archive/linux-2.6.11.12-xenU.patch

cd linux-2.6.11.12
patch -p1 < ../archive/linux-2.6.11.12-xenU.patch
cd ../
rm -fr install
mkdir install
cd linux-2.6.11.12-xenU
cp arch/xen/configs/xenU_defconfig .config
ARCH=xen; INSTALL_PATH=../install; INSTALL_MOD_PATH=../install
export ARCH INSTALL_PATH INSTALL_MOD_PATH
make oldconfig
make menuconfig

In the kernel comfiguration menu that shows up we have to enable quota and iptables as modules (it is important that they are modules. I could not get iptables to work in a virtual machine when I compiled it into the kernel statically!). This is where you enable these modules:

File systems --> [*] Quota support
<M> Old quota format support
<M> Quota format v2 support

Device Drivers ---> Networking support ---> Networking options ---> [*] Network packet filtering (replaces ipchains) ---> IP: Netfilter Configuration ---> <M> IP tables support (required for filtering/masq/NAT)

[*] means: build into the kernel statically.
<M> means: build as a kernel module.

Now we install the kernel to ~/xen/install:

make modules
make modules_install
make install

Finally, we copy the kernel to the "real" locations:

cd ../install/
cp boot/* /boot
cp -r lib/modules/2.6.11.12-xenU/ /lib/modules
cp -r usr/include/xen /usr/include

(This is my domU kernel configuration.)