Installation on Debian/old

OpenVZ consists of a kernel, user-level tools, and container templates.

This guide tells how to install the kernel and the tools on Debian Etch and Lenny.

For Etch users, this document explain how to partialy upgrade to Debian Lenny and install from lenny repositories (use this options at your risk).

Requirements

Filesystems

It is recommended to use a separate partition for container private directories (by default /var/lib/vz/private/<CTID>). The reason why you should do so is that if you wish to use OpenVZ per-container disk quota, you won't be able to use usual Linux disk quotas on the same partition. Bear in mind that per-container quota in this context includes not only pure per-container quota but also usual Linux disk quota used in container, not on HN.

At least try to avoid using root partition for containers because the root user of container will be able to overcome the 5% disk space barrier in some situations. If the HN root partition is completely filled, it will break the system.

OpenVZ per-container disk quota is supported only for ext2/ext3 filesystems so use one of these filesystems (ext3 is recommended) if you need per-container disk quota.

Repository setup (Etch only)

If you are using Debian Lenny, this step in no longer required. Openvz kernel packages and tools are available on main repository.

1. Using openvz.org repositories

At the moment two different repositories are online at http://download.openvz.org:

by Ola Lundqvist <opal@debian.org>

(OpenVZ kernels only)

apt-uri http://download.openvz.org/debian

by Thorsten Schifferdecker <tsd@debian.systs.org>

apt-uri http://download.openvz.org/debian-systs

(Mirror of OpenVZ Repository from http://debian.systs.org/)

Note: The next steps use the repository at http://download.openvz.org/debian-systs; the actual OpenVZ Tools for Debian exist only as unstable builds, see http://packages.debian.org/vzctl

Note: By default, on Ubuntu systems root tasks are executed with sudo

This can be achieved by the following commands, as root or as privileged "sudo" user

# echo -e "\ndeb http://download.openvz.org/debian-systs etch openvz" >> /etc/apt/sources.list
# wget -q http://download.openvz.org/debian-systs/dso_archiv_signing_key.asc -O- | apt-key add - && apt-get update

2. Using Debian repositories (upgrade to lenny)

There is even an lenny repository with kernel 2.6.28. Use it at your own risk!

Add lenny repositories to your /etc/apt/sources.list

deb http://DEBIAN-MIRROR/debian/ testing main
deb http://DEBIAN-MIRROR/debian-security/ testing/updates main

Enlarge apt-cache adding to /etc/apt/apt.conf this line:

APT::Cache-Limit "100000000";

Give etch package priority over lenny packages. Edit /etc/apt/preferences and set like this:

Package: *
Pin: release a=etch
Pin-Priority: 700

Package: *
Pin: release a=lenny
Pin-Priority: 650

Then apt-get update && apt-get dist-upgrade to upgrade to lenny.

Kernel installation

Lenny

aptitude install linux-image-openvz-686

this command will install latest kernel and all required packages and will arrange grub bootloader propertly.

Etch

1. Using openvz kernel repositories

Note: In case you want to recompile the OpenVZ kernel yourself on Debian, see Compiling the OpenVZ kernel (the Debian way).

First, you need to choose what kernel you want to install.

OpenVZ Kernel list built with kernel config from http://download.openvz.org

Kernel	Description	Hardware	Debian Architecture
ovzkernel-2.6.18	uniprocessor	up to 4GB of RAM	i386 and amd64
ovzkernel-2.6.18-smp	symmetric multiprocessor	up to 4 GB of RAM	i386 and amd64
ovzkernel-2.6.18-enterprise	SMP + PAE support + 4/4GB split	up to 64 GB of RAM	i386 only

OpenVZ Kernel list built with official Debian kernel config and OpenVZ Settings

Kernel	Description	Hardware	Debian Architecture
fzakernel-2.6.18-686	uni- and multiprocessor	up to 4GB of RAM	i386
fzakernel-2.6.18-686-bigmem	symmetric multiprocessor	up to 64 GB of RAM	i386
fzakernel-2.6.18-amd64	uni- and multiprocessor		amd64

 # apt-get install <kernel>

Configuring the bootloader

In case GRUB is used as the boot loader, it will be configured automatically, or execute update-grub; lines similar to these will be added to the /boot/grub/menu.lst file:

[...]
  title           Debian GNU/Linux, kernel 2.6.18-ovz-028stab051.1-686
  root            (hd0,1)
  kernel          /vmlinuz-2.6.18-ovz-028stab051.1-686 root=/dev/sda5 ro vga=791
  initrd          /initrd.img-2.6.18-ovz-028stab051.1-686
  savedefault
[...]

Note: per default on debian/ubuntu, a 2.6.22 kernel will boot before a 2.6.18, please check manually the grub boot order. See man update-grub for more details

Installing the user-level tools

OpenVZ needs some user-level tools installed. Those are:

vzctl

A utility to control OpenVZ containers (create, destroy, start, stop, set parameters etc.)

vzquota

A utility to manage quotas for containers. Mostly used indirectly (by vzctl).

 # [sudo] apt-get install vzctl vzquota

2 Using Debian lenny repositories

If you upgrade to lenny, you can search openvz kernel and can install with:

apt-get install linux-image-openvz-686

this command will install latest kernel and all required packages like:

 iproute libatm1 linux-image-2.6.26-1-openvz-686 linux-image-openvz-686 rsync vzctl vzquota

and will arrange grub bootloader propertly.

Rebooting into OpenVZ kernel

Warning: Before you restart your Server, keep in mind, that your system has all needed modules enabled; booting from your harddisk (e.g. hardware modules, raid system(s), lvm2 etc). May you need a INITRD (initramdisk) or compile needed kernel modules statically in.

Now reboot the machine and choose the OpenVZ Linux Kernel on the boot loader menu. If the OpenVZ kernel has been booted successfully, proceed to installing the user-level tools for OpenVZ.

Confirm proper installation

1. Kernel:

 # uname -r
 2.6.26-1-openvz-686
 #

2. Openvz kernel facility:

 # ps ax | grep vz
 2349 ?        S      0:00 [vzmond]

3. A network interface for containers:

 # ifconfig
 venet0    Link encap:UNSPEC  HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  
           UP BROADCAST POINTOPOINT RUNNING NOARP  MTU:1500  Metric:1
           RX packets:0 errors:0 dropped:0 overruns:0 frame:0
           TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
           collisions:0 txqueuelen:0 
           RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Configuring

sysctl

There are a number of kernel parameters that should be set for OpenVZ to work correctly. These parameters are stored in /etc/sysctl.conf file. Here is the relevant part of the file; please edit it accordingly.

Note: vzctl version from debian-systs, automate changing sysctl options for openvz

[...]

# On Hardware Node we generally need
# packet forwarding enabled and proxy arp disabled

net.ipv4.conf.default.forwarding=1
net.ipv4.conf.default.proxy_arp = 0
net.ipv4.ip_forward=1

# Enables source route verification
net.ipv4.conf.all.rp_filter = 1

# Enables the magic-sysrq key
kernel.sysrq = 1

# TCP Explict Congestion Notification
#net.ipv4.tcp_ecn = 0

# we do not want all our interfaces to send redirects
net.ipv4.conf.default.send_redirects = 1
net.ipv4.conf.all.send_redirects = 0

[...]

 # [sudo] sysctl -p

Note: You can make a symlink from /var/lib/vz to /vz as backward compatibility to OpenVZ as installed in other distributions (Debian vz root directory is /var/lib/vz to be FHS-compliant.

 # [sudo] ln -s /var/lib/vz /vz 

OS templates

To install a container, you need OS template(s).

Precreated templates can be found here.

You can create your own templates, see Debian template creation, Ubuntu Gutsy template creation and Category: Templates.

Note: Setup your prefered standard OS Template : edit the /etc/vz/vz.conf

 # [sudo] apt-get install vzctl-ostmpl-debian

Additional User Tools

vzprocps

A set of utilities to provide system information (vzps and vztop)

vzdump

A utility to backup and restore container.

 # [sudo] apt-get install vzprocps vzdump

Secure it

If you want to secure your container with individual firewall rules (instead or additionally to securing the host node) then you must run iptables inside the container. This works slightly different than on a physical server. So make sure that you check that iptables rules are indeed applied as expected inside the container.

Iptables modules required by the container must be specified in the general vz.conf file or the vzXXX.conf file of the container.

Add the following line into vz.conf to activate the respective iptables modules for all containers.

IPTABLES="ip_tables ipt_REJECT ipt_tos ipt_limit ipt_multiport iptable_filter iptable_mangle ipt_TCPMSS ipt_tcpmss ipt_ttl ipt_length ip_conntrack ip_conntrack_ftp ip_conntrack_irc ipt_LOG ipt_conntrack ipt_helper ipt_state iptable_nat ip_nat_ftp ip_nat_irc ipt_TOS"

[[1][Configure]] your iptable rules inside the container.

Warning: Note that iptables rules inside the container are not applied automatically as on a physical server by starting the iptables module! Follow the instructions below

To make sure the iptables rules are applied on a startup/reboot we'll create a new file:

nano /etc/network/if-pre-up.d/iptables

Add these lines to it:

#!/bin/bash
/sbin/iptables-restore < /etc/iptables.up.rules

The file needs to be executable so change the permissions:

chmod +x /etc/network/if-pre-up.d/iptables

Start iptables

/etc/init.d/iptables start

If the startup shows errors then you have probably not activated the needed iptables modules. See above.

Check inside the container that your iptables rules are indeed applied:

iptables -L

If the rules do not show up as you would expect on a physical server then you might not have activated the needed iptables modules.

Start it!

# [sudo] /etc/init.d/vz start

This does not make the vz system automatically start at boot time. For automatic start:

# [sudo] update-rc.d vz defaults 98

Use it!

After installing the OpenVZ kernel, user tools and a minimal OS template to create a first container and do some basic operations in OpenVZ environment. Read the download:doc/OpenVZ-Users-Guide.pdf, browse this wiki.