[Xen-users] openvswitch on xen 4.x

[Christopher Walker <kris240376@xxxxxxxxx>]

A huge thank you to mario from the 'openvswitch on Xen 4.1' post.  I
was having some trouble with using openvswitch with Xen 4.1 (I'm
currently migrating from 4.0.1) until I saw his post and noticed that
the xl.conf needed the full path to the networking script.  Made this
change and all is good now.  Thank you.

I would like to contribute what I have for using openvswitch with Xen.
 Again, I'm migrating from Xen 4.0.1 and can confirm that this works
for Xen 4.0.  Please feel free to provide feedback for Xen 4.1.
Please excuse the length of this post, I'm basically doing a dump of
the scripts that are on my hard drive for all to see and use.

The network-openvswitch script works with Xen 4.0 (xm) and Xen 4.1
(xm).  I'm using Slackware as my host and can provide the rc script
that I use to start and stop Xen if requested since I've basically
moved the contents of network-openvswitch into an rc script as part of
my migration to the xl toolchain.  The only bug I've noticed is that
the ports aren't cleaned up whenever xend is stopped.  I never
investigated this further and most likely never will since I'm moving
to the xl toolchain.

The vif-openvswitch script works for both Xen 4.0 (xm) and Xen 4.1
(xm/xl).  When I was first setting up Xen I was playing with VLAN
tagging for separating test domains so I designed the vif-network
script to handle tagging traffic on a port.  In order to take
advantage of tagging you must append the tag number to the bridge name
in your guest domain configuration file separated by a period.  i.e.,
vif = [ 'bridge=ovs0.3' ]

I hope this helps someone.  Enjoy and good luck!

/etc/xen/scripts/network-openvswitch:
#!/bin/bash
#============================================================================
# Default Xen network start/stop script.
# Xend calls a network script when it starts.
# The script name to use is defined in ${XEN_CONFIG_DIR}/xend-config.sxp
# in the network-script field.
#
# This script creates a virtual switch (default ${netdev}) and adds a
# device (defaults to eth0) to it.  The interface that this Open vSwitch
# is created on should not have a working IP address and will be used as
# a switch for Xen domU's.
#
# Usage:
# network-openvswitch (start|stop|status) {VAR=VAL}*
#
# Vars:
# bridge     The bridge to use (default xenvs0).
# netdev     The interface to add to the bridge (default eth0).
#
# start:
# Creates the bridge as bridge
# Enslaves netdev to bridge
#
# stop:
# Removes netdev from the bridge
# Deletes bridge
#
# status:
# Print addresses, interfaces
#
#============================================================================

dir=$(dirname "$0")
. "$dir/logging.sh"
. "$dir/xen-script-common.sh"
. "$dir/xen-network-common.sh"
. "$dir/locking.sh"

findCommand "$@"
evalVariables "$@"

netdev=${netdev:-eth0}
bridge=${bridge:-ovs0}

addr=`ip addr show dev ${netdev} | egrep '^ *inet' | sed -e 's/ *inet
//' -e 's/ .*//'`
if [ -n "$addr" ]; then
    echo "Invalid device: ${netdev} is up and has a valid IP address!" >&2
    exit 1
fi

show_status () {
    local dev=$1
    local bridge=$2

    echo '============================================================'
    echo 'vSwitch interfaces'
    ovs-vsctl list-ifaces ${bridge}
    echo ' '
    echo 'vSwitch ports'
    ovs-vsctl list-ports ${bridge}
    echo '============================================================'
}

op_start () {
    if [ "${bridge}" = "null" ] ; then
        return
    fi

    ifconfig "${netdev}" down
    ifconfig "${netdev}" 0.0.0.0 up
    ovs-vsctl -- --may-exist add-br ${bridge}
    ifconfig "${bridge}" 0.0.0.0 up
    ovs-vsctl -- --may-exist add-port ${bridge} ${netdev}

    # Remove any stale ports from last time virtual switch was running
    for port in $(ovs-vsctl list-ports ${bridge})
    do
        if [ "${port}" != "${netdev}" ]
        then
            ifconfig "${port}" down
            ovs-vsctl del-port ${port}
        fi
    done
}

op_stop () {
    if [ "${bridge}" = "null" ]; then
        return
    fi

    # Remove all ports from virtual switch
    for port in $(ovs-vsctl list-ports ${bridge})
    do
        ifconfig "${port}" down
        ovs-vsctl del-port ${port}
    done

    ifconfig "${bridge}" down
    ovs-vsctl -- --if-exists del-br ${bridge}
}

case "$command" in
    start)
        op_start
        ;;

    stop)
        op_stop
        ;;

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

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

/etc/xen/scripts/vif-openvswitch:
#!/bin/bash
#============================================================================
# ${XEN_SCRIPT_DIR}/vif-openvswitch
#
# Script for configuring a vif using Open vSwitch.
#
# Usage:
# vif-openvswitch (add|remove|online|offline)
#
# Environment vars:
# vif         vif interface name (required).
# XENBUS_PATH path to this device's details in the XenStore (required).
#
# Read from the store:
# bridge  bridge to add the vif to (optional).  Defaults to searching for the
#         bridge itself.
#
# up:
# Enslaves the vif interface to the bridge.
#
# down:
# Removes the vif interface from the bridge.
#============================================================================

dir=$(dirname "$0")
. "$dir/vif-common.sh"

bridge=${bridge:-}
bridge=$(xenstore_read_default "$XENBUS_PATH/bridge" "$bridge")

if [ -z "${bridge}" ]
then
  bridge=$(ovs-vsctl listbr | cut -d "
" -f 1)

  if [ -z "${bridge}" ]
  then
    fatal "Could not find bridge and none was specified"
  fi
fi

tag=${tag:-}

# Domain on VLAN tagged bridge?
RET=0
ovs-vsctl list-br | grep -c ${bridge} 1>/dev/null 2>&1 || RET=1
if [ $RET -eq 1 ]
then
  if [[ $bridge =~ \.[[:digit:]]{1,4}$ ]]
  then
    tag=$(echo ${bridge} | cut -d "." -f 2)
    bridge=$(echo ${bridge} | cut -d "." -f 1)
  else
    fatal "Could not find bridge device ${bridge}"
  fi
fi

RET=0
ovs-vsctl list-br | grep -c ${bridge} 1>/dev/null 2>&1 || RET=1
if [ $RET -eq 1 ]
then
  fatal "Could not find bridge device ${bridge}"
fi

if [ -z "${tag}" ]
then
  log debug "Successful vif-openvswitch $command for ${vif}, bridge ${bridge}."
else
  log debug "Successful vif-openvswitch $command for ${vif}, bridge
${bridge}, tag ${tag}."
fi

case "$command" in
  online)
    ifconfig "${vif}" 0.0.0.0 up
    if [ -z $tag ]
    then
      ovs-vsctl -- --may-exist add-port ${bridge} ${vif}
    else
      ovs-vsctl -- --may-exist add-port ${bridge} ${vif} tag=${tag}
    fi
    ;;

    offline)
      ovs-vsctl -- --if-exists del-port ${bridge} ${vif}
      ifconfig "$vif" 0.0.0.0 down
      ;;

    add)
      ;;
esac

if [ "$command" == "online" ]
then
  success
fi

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