FAQ
Coert,
To set up the networking, I basically used the following document:
http://et.redhat.com/~jmh/docs/Xen_networking.pdf

In this document, there is a reference to a different script for xen to use
to configure the networks. This script works, but I made two
modifications:
1) tweaked script so you could have an IP address on bond0 (untagged
traffic) and make that network accessible to the guests
2) added code so the networks could be configured with a configuration file
rather than editing the script

This is what the /etc/xen/net_bond.cfg file looks like:
# This file shows the mapping between the server interface, xen bridge and
virtual interface. The current code requires all three to be specified.
# bonded interface xen bridge name vif name
bond0.3 xenbr0 vif0.0
bond0.2 xenbr1 vif1.0
bond0.4 xenbr2 vif2.0
bond0.7 xenbr3 vif3.0
bond0.5 xenbr4 vif4.0
bond0.6 xenbr5 vif5.0
bond0 xenbr6 vif6.0


This is what that script looks like now:
#!/bin/sh

# Usage: transfer_addrs src dst
# Copy all IP addresses (including aliases) from device $src to device $dst.
transfer_addrs () {
local src=$1
local dst=$2
# Don't bother if $dst already has IP addresses.
if ip addr show dev ${dst} | egrep -q '^ *inet ' ; then
return
fi
# Address lines start with 'inet' and have the device in them.
# Replace 'inet' with 'ip addr add' and change the device name $src
# to 'dev $src'.
ip addr show dev ${src} | egrep '^ *inet ' | sed -e "
s/inet/ip addr add/
s@\([0-9]\+\.[0-9]\+\.[0-9]\+\.[0-9]\+/[0-9]\+\)@\1@
s/${src}/dev ${dst}/
" | sh -e
# Remove automatic routes on destination device
ip route list | sed -ne "
/dev ${dst}\( \|$\)/ {
s/^/ip route del /
p
}" | sh -e
}

# Usage: transfer_routes src dst
# Get all IP routes to device $src, delete them, and
# add the same routes to device $dst.
# The original routes have to be deleted, otherwise adding them
# for $dst fails (duplicate routes).
transfer_routes () {
local src=$1
local dst=$2
# List all routes and grep the ones with $src in.
# Stick 'ip route del' on the front to delete.
# Change $src to $dst and use 'ip route add' to add.
ip route list | sed -ne "
/dev ${src}\( \|$\)/ {
h
s/^/ip route del /
P
g
s/${src}/${dst}/
s/^/ip route add /
P
d
}" | sh -e
}



# Usage: create_bridge bridge
create_bridge () {
local bridge=$1

# Don't create the bridge if it already exists.
if ! brctl show | grep -q ${bridge} ; then
brctl addbr ${bridge}
brctl stp ${bridge} off
brctl setfd ${bridge} 0
fi
ip link set ${bridge} up
}

# Usage: add_to_bridge bridge dev
add_to_bridge () {
local bridge=$1
local dev=$2
# Don't add $dev to $bridge if it's already on a bridge.
if ! brctl show | grep -q ${dev}$ ; then
brctl addif ${bridge} ${dev}
fi
}

# Usage: show_status dev bridge
# Print ifconfig and routes.
show_status () {
local dev=$1
local bridge=$2

echo '============================================================'
ip addr show ${dev}
ip addr show ${bridge}
echo ' '
brctl show ${bridge}
echo ' '
ip route list
echo ' '
route -n
echo '============================================================'
}

op_start () {
if [ -f /etc/xen/net_bond.cfg ] ; then
grep ^bond /etc/xen/net_bond.cfg | while read bond bridge vif
do
create_bridge $bridge
add_to_bridge $bridge $vif
add_to_bridge2 $bridge $bond

transfer_addrs $bond $bridge
transfer_routes $bond $bridge
done
fi

}

op_stop () {
if [ -f /etc/xen/net_bond.cfg ] ; then
grep ^bond /etc/xen/net_bond.cfg | while read bond bridge vif
do
transfer_routes $bridge $bond
ip link set $bridge down
brctl delbr $bridge
done
fi
}

# adds $dev to $bridge but waits for $dev to be in running state first
add_to_bridge2() {
local bridge=$1
local dev=$2
local maxtries

echo -n "Waiting for ${dev} to negotiate link."
for i in `seq ${maxtries}` ; do
if ifconfig ${dev} | grep -q RUNNING ; then
break
else
echo -n '.'
sleep 1
fi
done

if [ ${i} -eq ${maxtries} ] ; then echo '(link isnt in running state)' ;
fi

add_to_bridge ${bridge} ${dev}
}

case "${1}" in
start)
op_start
;;

stop)
op_stop
;;

status)
show_status ${netdev} ${bridge}
;;

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

David

On Mon, Aug 3, 2009 at 3:17 AM, Coert Waagmeester wrote:

On Fri, 2009-07-31 at 11:08 -0400, David Knierim wrote:
I am running CentOS 5.3 x86_64 as my dom0 and CentOS 5.3 on my domU's.
On the dom0, I have two interfaces that are bonded and have tagged
VLANs. I can get the networks to the domU's by creating a bridge for
each of the VLANS (bond0.3, bond0.4, etc). On the domU, the
interfaces show up as eth0, eth1, etc.

Is there a way to set up the network on the dom0 so my domU's see a
single interface with tagged VLAN support??

Thanks!
David
_______________________________________________
CentOS-virt mailing list
CentOS-virt at centos.org
http://lists.centos.org/mailman/listinfo/centos-virt
Hello David,

Sorry this is not an answer to your question, but how did you set up the
bonds with xen?

I tried doing the same, and did not win....


Regards,

Coert

_______________________________________________
CentOS-virt mailing list
CentOS-virt at centos.org
http://lists.centos.org/mailman/listinfo/centos-virt
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