Virtual network device

Virtual network device (venet) is the default network device for a container. This network device looks like a point-to-point connection between container and the host system. It does packet switching based on IP header. This is a default network device for container (an alternative is veth device).

Venet device is created automatically on container start. Vzctl scripts set up an appropriate IP address and other settings on venet inside a container.

Kernel module

First of all, check that vznetdev module is loaded:

# lsmod | grep vznetdev

If it is not, load the module:

# modprobe vznetdev

You might want to check /etc/init.d/vz script to make sure the module gets loaded during startup.

Adding IP address to a container

vzctl set <CTID> --ipadd <IP1>[,<IP2>,...] [--save]

Note: This option is incremental, so IP addresses are added to already existing ones.

Example

vzctl set 101 --ipadd 10.0.0.1 --save

After executing this command IP address 10.0.0.1 will be added to container 101 and IP configuration will be saved to a container configuration file.

Removing IP address from a container

vzctl set <CTID> --ipdel <IP1>[,<IP2>,...] [--save]
vzctl set <CTID> --ipdel all [--save]

Example

vzctl set 101 --ipdel 10.0.0.1

After executing this command IP address 10.0.0.1 will be removed from container 101, but IP configuration will not be changed in container config file. And after container reboot IP address 10.0.0.1 will be assigned to this container again.

Sysctl

You will need to configure some sysctl parameters to get your venet devices working. Please have a look at the Installation_on_Debian#sysctl section.

IPv6

If you expect any problems with configuring IPv6 for your CTs, this OpenVZ forum thread might help:

http://forum.openvz.org/index.php?t=msg&goto=14752&

See also

• Veth
• Differences between venet and veth