ADMIN

Virtualization
OpenVZ
Figure 3: I installing OpenVZ from the package sources for Ubuntu 8.04 – the
last version of Ubuntu to officially include an OpenVZ kernel. The only package
needed for this was the linux‐openvz meta-package.
Figure 4: The OpenVZ developers provide container templates for various guest
systems; this makes installing a guest system a quick and easy experience.
Templates from the community are also available.
should have at least 5GB of hard disk
space, a fair amount of RAM (at least
4GB), and enough swap space.
Starting OpenVZ
Installing OpenVZ is simple. Users on
RPM-based operating systems such as
RHEL or CentOS can simply include
the Yum repository specified in the
quick install manual on the project
homepage. Ubuntu 8.04 users will
find a linux‐openvz meta-package
in the multiverse repository, which
installs the required OpenVZ kernel,
including the kernel modules and
header files (Figure 3). At the time of
writing, no OpenVZ kernel was available
for Ubuntu 10.04. If you are interested
in using OpenVZ with a current
version of Ubuntu, you will find
a prebuilt deb package in Debian’s
unstable branch. To install type:
detailed information on this, refer to
the sysctl section in the quick install
guide, which covers providing network
access to the guest systems, involving
setting up packet forwarding
for IPv4 [5]. Then, you need to reboot
with the new kernel. If you edit
sysctl after rebooting, you can reload
by typing sudo sysctl ‐p. Typing
sudo /etc/init.d/vz start
wakes up the virtualization machine.
Next, you should make sure all the
OpenVZ services are running; this is
done easily (on Ubuntu) by issuing:
sudo sysv‐rc‐conf ‐list vz
If the tool is missing, you can type
sudo apt‐get install sysconfig
to install it. Debian and Red Hat users
can run the legacy chkconfig tool. A
check of service vz status should
now tell you that OpenVZ is running.
Container Templates
OpenVZ users don’t need to install
an operating system in the traditional
sense of the word. The most convenient
approach to set up OpenVZ
containers is with templates (i.e.,
tarballs with a minimal version of the
distribution you want to use in the
container). Administrators can create
templates themselves, although it’s
not exactly trivial [6]. Downloading
prebuilt templates [7] and copying
them to the template folder is easier:
sudo cp path_to_template U
/var/lib/vz/template/cache
Besides templates provided by the
OpenVZ team, the page also offers
sudo dpkg ‐i linux‐base_2.6.32‐10_all.debU
linux‐image‐2.6.32‐4‐openvz‐686_U
2.6.32‐10_i386.deb
The sudo apt‐get ‐f install command
will automatically retrieve any
missing packages. You will also need
to install the vzctl tool, which has a
dependency for vzquota.
Before setting up the containers and
configuring the OpenVZ host environment,
you need to modify a few
kernel parameters that are necessary
to run OpenVZ in the /etc/sysctl.
conf file on the host system. For more
Figure 5: A couple of clear-cut commands are used for creating and starting a VE and for entering the VE.
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