Specifications

Configuring for Use on a Network

Integrating Red Hat Virtualization into your network architecture is a complicated process and

depending upon your infrastructure, may require custom configuration to deploy multiple

ethernet interfaces and setup bridging.

Each domain network interface is connected to a virtual network interface in dom0 by a point to

point link. These devices are vif<domid> and <vifid>. vif1.0 for the first interface in domain

1; vif3.1 for the second interface in domain 3.

Domain0 handles traffic on these virtual interfaces by using standard Linux conventions for

bridging, routing, rate limiting, etc. The xend daemon employs two shell scripts to perform initial

configuration of your network and new virtual interfaces. These scripts configure a single bridge

for all virtual interfaces. You can configure additional routing and bridging by customizing these

scripts.

Red Hat Virtualization's virtual networking is controlled by the two shell scripts, network-bridge

and vif-bridge. xend calls these scripts when certain events occur. Arguments can be passed

to the scripts to provide additional contextual information. These scripts are located in the

/etc/xen/scripts directory. You can change script properties by modifying the

xend-config.sxp configuration file located in the /etc/xen directory.

network-bridge — When xend is started or stopped, this script initializes or shuts down the

virtual network. Then the configuration initialization creates the bridge xen—br0 and moves eth0

onto that bridge, modifying the routing accordingly. When xend finally exits, it deletes the bridge

and removes eth0, thereby restoring the original IP and routing configuration.

vif-bridge is a script that is invoked for every virtual interface on the domain. It configures

firewall rules and can add the vif to the appropriate bridge.

There are other scripts that you can use to help in setting up Red Hat Virtualization to run on

your network, such as network-route, network-nat, vif-route, and vif-nat. Or these

scripts can be replaced with customized variants.

Chapter 12.