C.5.1 Setting up the virtual network on the host OS

Set up the virtual network of the virtual machine function on the host OS. The virtual network is set only for one NIC when the operating system is installed (default). To establish a highly reliable network, set the virtual network to use multiple NICs. For details, see "Virtual Machine User's Guide".

Create a shell script for creating the virtual bridge, and set so that GLS-specific scripts are executed in the following order.

Creating the virtual bridge
Set so that the GLS-specific stop script (/opt/FJSVhanet/local/sbin/hanetxen stop) is executed before the virtual bridge is created (op_start) and the GLS-specific start script (/opt/FJSVhanet/local/sbin/hanetxen start) is executed after the virtual bridge is created.
Deleting the virtual bridge
Set so that the GLS-specific stop script is executed before the virtual bridge is deleted (op_stop).

The following is a setting example in which the name of the shell script to be created is network-bridge-gls.

/etc/xen/scripts/network-bridge-gls

#!/bin/sh
#
# Sample of Create/Delete virtual bridge
#
# $1 start : Create virtual bridge
#    stop  : Delete virtual bridge
#    status: Display virtual bridge information

# Exit if anything goes wrong
#set -e

command=$1
xenscript=/etc/xen/scripts/network-bridge
glsxenscript=/opt/FJSVhanet/local/sbin/hanetxen

# op_start:subscript for start operation #
op_start () {

         $xenscript $command vifnum=0 netdev=eth0
         $xenscript $command vifnum=1 netdev=eth1

}

# op_stop:subscript for stop operation #
op_stop () {
         # same operation as start
         op_start
}

case "$command" in
         start)
                  # Create your virtual bridge
                  $glsxenscript stop
                  op_start
                  $glsxenscript start
         ;;

         stop)
                  # Delete virtual bridge
                  $glsxenscript stop
                  op_stop
         ;;

         status)
                  # display virtual bridge information
                  $xenscript status
         ;;

         *)
                  echo "Unknown command: $command" >&2
                  echo 'Valid commands are: start, stop, status' >&2
                  exit 1

esac

Information

Setting up a virtual network differs between RHEL5 and RHEL5.1. For RHEL5, set "$xenscript $command vifnum=X netdev=ethX" rather than "$xenscript $command vifnum=X".
In "C.4.1 Configuration for creating a highly reliable network of guest domains with GLS on domain-0 (Configuration 1)", delete the line of "set -e" from the script.

Save the created script in "/etc/xen/scripts".

# cp network-bridge-gls /etc/xen/scripts
# cd /etc/xen/scripts
# chmod +x network-bridge-gls

Edit the "network-script" parameter in the configuration file (/etc/xen/xend-config.sxp) of the xend service. "network-bridge" is set for the "network-script" parameter. Rename it to the name of the script you created.

# Your default ethernet device is used as the outgoing interface, by default.
# To use a different one (e.g. eth1) use
#
# (network-script 'network-bridge netdev=eth1')
#
# The bridge is named xenbr0, by default.  To rename the bridge, use
#
# (network-script 'network-bridge bridge=<name>')
#
# It is possible to use the network-bridge script in more complicated
# scenarios, such as having two outgoing interfaces, with two bridges, and
# two fake interfaces per guest domain.  To do things like this, write
# yourself a wrapper script, and call network-bridge from it, as appropriate.
#
(network-script network-bridge-gls)

Note

If you create the virtual brige with device number 4 or more (xenbrX, X is more than 4), add the nloopbacks setting in the /etc/modprobe.conf file. A nloopbacks is set to the value which is the maximum number of virtual bridge device numbers plus 1. For details, see the RHEL manuals. The following is an example in which the virtual bridge with device number up to 5 (xenbrX, X is from 0 to 5) is created.

# options netloop nloopbacks=6