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 or Lenny.
For Etch users, this document explains how to partially upgrade to Debian Lenny and install from lenny repositories (use this options at your risk).
Contents
Requirements
Filesystems
It's recommended that you use a separate partition for container private
directories (by default /var/lib/vz/private/<CTID>). The reason for this is that if you wish to use the 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 the usual Linux disk quota used in container, not on the HN.
At the very least try to avoid using the root partition for containers, because the root user of a 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; therefore it makes sense to 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/)
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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 |
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Note: By default, on Ubuntu systems root tasks are executed with sudo |
This can be done via 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 a 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 accordingly.
Etch
1. Using openvz kernel repositories
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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.
| 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 |
| 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 [...]
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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:
apt-get install 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
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Warning: Before you restart your Server, verify that your system has all needed modules enabled in order to boot your harddisk (e.g. hardware modules, raid system(s), lvm2 etc). You may need an INITRD (initramdisk) or to compile needed kernel modules statically. |
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.
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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
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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
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Note: Support of OS templates on 64 bit hosts is somewhat limited for the time being, so that not all tools or features are available - please see Making template tools to work on x86_64 and Install OpenVZ on a x86 64 system Centos-Fedora for additional details and information on possible workarounds |
To install a container, you need OS template(s).
Precreated templates can be found here and here.
You can create your own templates, see Debian template creation, Ubuntu Gutsy template creation and Category: Templates.
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Note: Setup your prefered standard OS Template : edit the /etc/vz/vz.conf |
# [sudo] apt-get install vzctl-ostmpl-debian-5.0-i386-minimal
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.
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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.