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).
Contents
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. mmm
Etch
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
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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
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.
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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.
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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.