Description of problem:
The file /etc/xen/xend-config.xsp allows for tweaking the default network script for xenbridges configuration. The default is (network-script network-bridge).

When used with cman the bridges are started from the cman init script. In RHEL-5.2 this uses the following script fragment:

xend_bridged_net_start() {
    if [ ! -x /etc/xen/scripts/network-bridge ]; then
        if [ -f /etc/xen/scripts/network-bridge ]; then
            errmsg='The xend bridged network script cannot be run'
        else
            errmsg='The xend bridged network script is missing'
        fi
        return 1
    fi
    
    /sbin/modprobe netbk >& /dev/null
    /sbin/modprobe netloop >& /dev/null
    bridge_parms=`egrep -m 1 "^[[:blank:]]*\([[:blank:]]*network-script[[:blank:]]+(')?[[:blank:]]*network-bridge([[:blank:]]*\)|[[:blank:]]+)" /etc/xen/xend-config.sxp| sed -r "s/^[[:blank:]]*\([[:blank:]]*network-script[[:blank:]]+'?[[:blank:]]*network-bridge[[:blank:]]*//; s/'?[[:blank:]]*\).*//"`
    errmsg=$(/etc/xen/scripts/network-bridge start $bridge_parms 2>&1) || return 1
    return 0
}

This seems to hard code the path to the script:

    errmsg=$(/etc/xen/scripts/network-bridge start $bridge_parms 2>&1) || return 1

Although it does retrieve customised parameters from xend-config.sxp and applies these when starting the bridge.

Version-Release number of selected component (if applicable):
cman-2.0.84-2.el5

How reproducible:
100%

Steps to Reproduce:
1. Configure a custom bridge script in xend-config.sxp, e.g. add:

(network-script mynetwork)

2. Create the mynetwork script in the /etc/xen/scripts directory
3. Start cman services
  
Actual results:
No bridges are started

Expected results:
Custom bridge script runs. Bridges start.

Additional info: