Re: [Xen-users] Bridging configuration issue

[Robert Smol <eagtstools@xxxxxxx>]

Hello again,
after another night of investigating I found following:

I can't use dummy interface.?.

Kernel configuration help says it is bit bucket interface where packets
go into oblivion. Anyway I thought it should not matter as dummy0 is
renamed to pdummy0 and vethX is used as dummy0. Bridge is created,
however when I run dhcpd it says  in the log:

No subnet declaration for dummy0 (0.0.0.0).

Even if dummy0 (vethX) is configured properly. Once I rename dummy0 to
vethX (i.e. veth5) everything works (DCHP). 


When I use eth1 (another spare real Ethernet port), everything works out
of the box. Then I looked into Documentation again to understand that I
can use vethX interfaces and tried to build bridge without netdev by
hand.

I've managed to build bridges with vethx that were working perfectly,
however I did not find a way to use network-bridge script because it
requires netdev parameter. 


Hence my question, is there any possibility to use network-bridge script
to create only simple bridges with vethX interface and no netdev? So I
can than use this vethX as a GW to the network of related domU's. Or is
there anything wrong with my DHCPD (ISC) that is doesn't work until the
dummy0 is renamed to vethx?


my updated picture of requested setup:


dom0:                                                           domU's:

                          +---- xenbr0--------------------+
 +------+                 |   +--------+       +--------+ |      +-----+
 |veth5 | <--connected to --> | vif0.5 | <   > | vif1.0 | <---> | eth0|
 +------+                 |   +--------+       +--------+ |      +-----+
                          |                               |
                          |                    +--------+ |     +------+
                          |                    | vif2.0 | <---> | eth0 |
                          |                    +--------+ |     +------+
                          +-------------------------------+


                          +---- xenbr6--------------------+
 +------+                 |   +--------+       +--------+ |      +-----+
 |veth6 | <--connected to --> | vif0.6 | <   > | vif3.0 | <---> | eth0|
 +------+                 |   +--------+       +--------+ |      +-----+
                          |                               |
                          |                    +--------+ |     +------+
                          |                    | vif4.0 | <---> | eth0 |
                          |                    +--------+ |     +------+
                          +-------------------------------+



Best regards,

Robert



On Mon, 2006-07-31 at 16:35 +0200, Robert Smol wrote:
> Hello Xen people,
> 
> I'm new to Xen and I'm trying to have domUs on separate network and have
> their IP's assigned by DHCP server running in dom0.
> 
> 
> here is desired picture
> 
> 
> dom0:                                                       domU:
> 
>   +------+                     +--------+      +--------+       +-----+
>   |dummy0| <--connected to --> | xenbr0 | <--- | vif1.0 | <---> | eth0|
>   +------+                     +--------+      +--------+       +-----+
> 
> I would like to have several dummy interfaces each as a GW to group of
> domUs.
> 
> 
> I have interface dummy0 configured as 192.168.3.1. I ran network-bridge
> script with netdev=dummy0 and it created following configuration:
> 
> created bridge xenbr0
> dummy0 -> pdummy0 and connected to xenbr0
> veth0 ->dummy0 and it has IP settings 192.168.3.1, vif0.0 is connected
> to xenbr0
> 
> so far so good
> 
> when I start domU, I see vif-bridge correctly connects vif1.0 to bridge
> and when in domU I genereate traffic I can see that on xenbr0:
> 
> node001 scripts # tcpdump -i xenbr0 -vv
> tcpdump: WARNING: xenbr0: no IPv4 address assigned
> tcpdump: listening on xenbr0, link-type EN10MB (Ethernet), capture size
> 96 bytes
> 18:16:30.998373 IP (tos 0x0, ttl  64, id 23255, offset 0, flags [none],
> proto: UDP (17), length: 576) 0.0.0.0.bootpc > 255.255.255.255.bootps:
> BOOTP/DHCP, Request from aa:00:00:50:02:f1 (oui Unknown), length: 548,
> xid:0xc1897f65, secs:10, flags: [none] (0x0000)
>           Client Ethernet Address: aa:00:00:50:02:f1 (oui Unknown) [|
> bootp]
> 
> 
> However I can't see any traffic from pdummy0 nor vif0.0 (which I expect
> to be interconnected to dummy0). And DHCP fails. When I try to set eth0
> in domU to same range as dummy0 (e.g 192.168.3.10) and ping dummy0, no
> traffic can be seen as well.
> 
> Any ideas what am I missing? I am also not sure why pdummy0 is needed in
> the bridge (no real dev). I've read a lot of docs, but can't solve it.
> 
> 
> bridge:
> node001 ~ # brctl show
> bridge name     bridge id               STP enabled     interfaces
> xenbr0          8000.feffffffffff       no              vif0.0
>                                                         pdummy0
>                                                         vif1.0
> 
> 
> ip link shows:
> 3: dummy0: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue
>     link/ether a6:de:f2:36:a4:11 brd ff:ff:ff:ff:ff:ff
> 4: vif0.1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
>     link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
> 
> 
> 
> Robert
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-users
> 


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