[Xen-users] DomU strange network behavior

["Andrew Deagman" <andrew@xxxxxxxxxx>]

I  am experiencing strange network behavior from several DomU's. I can ssh from DomU to any host on the local lan/vlan, I can ping those hosts. However when I go to resolve a hostname DNS fails. I have verified that three other DomU's are exhibiting the same behavior. I have also verified that Dom0 is functioning properly and can resolve hostnames and access hosts outside of the lan/vlans. Any ideas on what is going on? I have verified that networking looks to be working properly.  I am using a custom network script and Ethernet bonding. This has me particularly stumped as I do not see anything in the logs to indicate why name resolution would be failing. Here is the output of my configuration. If more information is needed let me know.

Thanks
Andrew


badm01::# brctl show
bridge name    bridge id        STP enabled    interfaces
virbr0        8000.000000000000    yes        
xenbr0        8000.00219bfbd4f1    yes        vif1.0
                            bond0
badm01::# 

badm01::# cat /etc/xen/scripts/network-bridge-bond 
#!/bin/sh

# Usage: transfer_addrs src dst
# Copy all IP addresses (including aliases) from device $src to device $dst.
transfer_addrs () {
    local src="">    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="">    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 () {
    create_bridge xenbr0
    add_to_bridge xenbr0 vif0.0
    add_to_bridge2 xenbr0 bond0

    transfer_addrs bond0 xenbr0
    transfer_routes bond0 xenbr0
}

op_stop () {
    transfer_routes xenbr0 bond0
    ip link set xenbr0 down
    brctl delbr xenbr0

}

# 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=10

    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

badm01::# 

badm01::# less btst 
name = "btst"
uuid = "7da402c9-603c-b2bc-b385-a2a711fbf6d9"
maxmem = 256
memory = 256
vcpus = 1
bootloader = "/usr/bin/pygrub"
>>>vfb = [  ]
disk = [ "tap:aio:/opt/xen/images/btst,xvda,w" ]
vif = [ "mac=00:16:3e:62:15:fb,bridge=xenbr0" ]
badm01::# 


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