3 Preparing The Physical Nodes

node1/node2:

First we update the packages database:

apt-get update

Then we install OpenSSH and a full-featured vim text editor (unless you prefer another text editor such as nano):

apt-get install ssh openssh-server vim-full

node1:

Because the Debian Etch installer has configured our system to get its network settings via DHCP, we have to change that now because a server should have a static IP address. Edit /etc/network/interfaces and adjust it to your needs (please note that I replace allow-hotplug eth0 with auto eth0; otherwise restarting the network doesn't work, and we'd have to reboot the whole system):

vi /etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#allow-hotplug eth0
#iface eth0 inet dhcp
auto eth0
iface eth0 inet static
        address 192.168.0.100
        netmask 255.255.255.0
        network 192.168.0.0
        broadcast 192.168.0.255
        gateway 192.168.0.1

Then restart your network:

/etc/init.d/networking restart

Then edit /etc/hosts. Make it look like this:

vi /etc/hosts

127.0.0.1       localhost.localdomain   localhost
192.168.0.100   node1.example.com       node1           cluster1.example.com    cluster1
192.168.0.101   node2.example.com       node2
192.168.0.105   inst1.example.com       inst1

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

Next we must make sure that the commands

hostname

and

hostname -f

print out the full hostname (node1.example.com). If you get something different (e.g. just node1), do this:

echo node1.example.com > /etc/hostname
/etc/init.d/hostname.sh start

Afterwards, the hostname commands should show the full hostname.

node2:

Now we do the same again on node2.example.com:

vi /etc/network/interfaces

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#allow-hotplug eth0
#iface eth0 inet dhcp
auto eth0
iface eth0 inet static
        address 192.168.0.101
        netmask 255.255.255.0
        network 192.168.0.0
        broadcast 192.168.0.255
        gateway 192.168.0.1

/etc/init.d/networking restart

vi /etc/hosts

127.0.0.1       localhost.localdomain   localhost
192.168.0.100   node1.example.com       node1           cluster1.example.com    cluster1
192.168.0.101   node2.example.com       node2
192.168.0.105   inst1.example.com       inst1

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

echo node2.example.com > /etc/hostname
/etc/init.d/hostname.sh start

node1/node2:

Edit /etc/apt/sources.list. Comment out the CD. It should look like this:

vi /etc/apt/sources.list

#
# deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 NETINST Binary-1 20070407-11:29]/ etch contrib main

#deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 NETINST Binary-1 20070407-11:29]/ etch contrib main

deb http://ftp2.de.debian.org/debian/ etch main
deb-src http://ftp2.de.debian.org/debian/ etch main

deb http://security.debian.org/ etch/updates main contrib
deb-src http://security.debian.org/ etch/updates main contrib

Then run

apt-get update

to update the apt packages database and

apt-get upgrade

to install the latest updates (if there are any). Afterwards, install the build-essential package:

apt-get install build-essential

4 Installing Xen

node1/node2:

Next we install Xen on both physical nodes:

apt-get install xen-linux-system-2.6.18-5-xen-686 libc6-xen

Then we edit /etc/xen/xend-config.sxp and modify the dom0-min-mem line so that it looks like this:

vi /etc/xen/xend-config.sxp

[...]
# Dom0 will balloon out when needed to free memory for domU.
# dom0-min-mem is the lowest memory level (in MB) dom0 will get down to.
# If dom0-min-mem=0, dom0 will never balloon out.
(dom0-min-mem 0)
[...]

Next open /boot/grub/menu.lst and find the # xenhopt= and # xenkopt= lines and modify them as follows (don't remove the # at the beginning!):

vi /boot/grub/menu.lst

[...]

## Xen hypervisor options to use with the default Xen boot option
# xenhopt=dom0_mem=64M

## Xen Linux kernel options to use with the default Xen boot option
# xenkopt=console=tty0 nosmp
[...]

(Remember what I said about memory in chapter 1. If you have enough RAM, you should probably use 256M or 512M here, at least on production systems.)

Afterwards, update the GRUB boot loader:

update-grub

and reboot both physical nodes:

shutdown -r now

At the boot prompt, select the new Xen kernel and boot from it.

After the nodes have come up, do this:

cd /boot
ln -s vmlinuz-`uname -r` vmlinuz-2.6-xenU
ln -s initrd.img-`uname -r` initrd-2.6-xenU

5 Installing DRBD

node1/node2:

Next we install DRBD:

apt-get install drbd0.7-module-source drbd0.7-utils

Now we must compile and enable the DRBD kernel module:

m-a update

m-a a-i drbd0.7

echo drbd minor_count=64 >> /etc/modules
modprobe drbd minor_count=64