(don't top post)
Il Thu, Jul 12, 2007 at 03:56:07PM +0300, David Shwatrz ha scritto:
> Hello,
> And I just want to add some info :
>
> running :
> "brctl show"
>
> gives:
> bridge name bridge id STP enabled interfaces
> virbr0 8000.000000000000 no
>
> which means that there is no interface enslaved to this bridge.
Hum, this depends on what the script (/etc/kvm/kvm-ifup, or
/etc/qemu-ifup) is doing...
> On 7/12/07, David Shwatrz <[EMAIL PROTECTED]> wrote:
> >
> >Thanks;
> >I am not sure I got you !
> >running "ifconfig -a " on the host shows the following:
> >
> >eth0 Link encap:Ethernet HWaddr 00:1B:24:1D:EC:C0
> > inet addr: 192.168.0.31 Bcast:192.168.0.255 Mask:255.255.255.0
> > inet6 addr: fe80::21b:24ff:fe1d:ecc0/64 Scope:Link
> > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> > RX packets:10164222 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:95594 errors:0 dropped:0 overruns:0 carrier:0
> > collisions:0 txqueuelen:1000
> > RX bytes:3427235680 (3.1 GiB) TX bytes:27635785 (26.3 MiB)
> > Interrupt:19
> >
> >
> >lo Link encap:Local Loopback
> > inet addr:127.0.0.1 Mask:255.0.0.0
> > inet6 addr: ::1/128 Scope:Host
> > UP LOOPBACK RUNNING MTU:16436 Metric:1
> > RX packets:5821 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:5821 errors:0 dropped:0 overruns:0 carrier:0
> > collisions:0 txqueuelen:0
> > RX bytes:804856 (785.9 KiB) TX bytes:804856 (785.9 KiB)
> >
> >virbr0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
> > inet addr: 192.168.122.1 Bcast:192.168.122.255 Mask:
> >255.255.255.0
> > inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
> > UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
> > RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> > TX packets:93 errors:0 dropped:0 overruns:0 carrier:0
> > collisions:0 txqueuelen:0
> > RX bytes:0 (0.0 b) TX bytes:21586 ( 21.0 KiB)
This configuration is a bit different from the one described in
the first mail though.
> >As you can see, there is not "sit" interface here. There is a virbr0
> >(bridge) but on 192.168.122.1
sit0 is the TUN device used by default, i.e. unless you're passing
-no-tap to the kvm script. If you're calling the qemu binary without
using the 'kvm' python wrapper then you should use something like this:
/path/to/kvm/qemu-whatever -hda disk-image.qcow -cdrom cd.iso -net tap
-net nic (plus optional stuff)
So: how are you creating the virtual machine? What is the content of the
network startup file?
Your kernel must also support the TUN device (CONFIG_TUN).
> >Please advice; also if you can please send the script, maybe I can get
> >some ideas from it regarding what to do.
$ cat /etc/kvm/kvm-ifup
#!/bin/sh
BRIDGE_DEV=br0
BRIDGE_ADDR=172.20.0.1/16
BRIDGE_BCAST=172.20.255.255
BRIDGE_ADDR6=fec0:2::1/64
#MAINIF=eth1
#set -x
ip link show dev $BRIDGE_DEV > /dev/null 2>&1
if [ $? -ne 0 ]; then
# Set up the bridge
brctl addbr $BRIDGE_DEV
if [ -n $MAINIF ]; then
ip link set $MAINIF up
brctl addif $BRIDGE_DEV $MAINIF
fi
ip addr add $BRIDGE_ADDR broadcast $BRIDGE_BCAST dev $BRIDGE_DEV
if [ -n $BRIDGE_ADDR6 ]; then
ip addr add $BRIDGE_ADDR6 dev $BRIDGE_DEV
if [ -e /etc/init.d/radvd ]; then
/etc/init.d/radvd reload
fi
fi
ip link set $BRIDGE_DEV up
fi
# Add new interface
ip link set $1 up
brctl addif $BRIDGE_DEV $1
The configuration is done with the vars at the beginning. What the
script does is:
- Check whether the bridge $BRIDGE_DEV is alread there, if not:
- Create the bridge
- Enslave $MAINIF, if required. This can be used to e.g. create a
bridged ethernet with one of your NICs. Leave MAINIF empty if you
want to use a separate subnet for the VMs.
- Configure IPv6, is requested
- Enslave the new interface ($1)
Note that if the bridge with the VMs is on a separate network (in your
case the LAN on eth0 is 192.168.0.0/24, while the "virtual" LAN is
192.168.122.0/24) you must enable the forwarding between the 2
interfaces:
# echo 1 > /proc/sys/net/ipv4/ip_forward
This allows the guest to talk with the host. To communicate with an
external host (be it another machine on the LAN or a server on the
Internet) you'll have to set up a NAT (or - simpler - MASQUERADE) with
iptables.
This setup allows you to make a clear separation between the VMs and the
rest of the net. Of course you can also create a bridge with eth0 and
the interface of the VM (e.g. set MAINIF="eth0" in my script) and it
will "just work".
Option 3 is: forget about the bridge and do the routing at IP level.
HTH,
Luca
--
Dicono che il cane sia il miglior amico dell'uomo. Secondo me non e`
vero. Quanti dei vostri amici avete fatto castrare, recentemente?
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