Re: [Xen-users] Xen Networking problem!

Todd Deshane
Fri, 01 Aug 2008 15:56:58 -0000

On Fri, Aug 1, 2008 at 4:32 AM, Stéphane Cesbron
<Stephane.Cesbron@inserm.fr> wrote:
> Hi,
>
> I ''ve got a CentOS 5.2 server running xen 3.0 with 2 DomUs also
running
> CentOS 5.2.
> All my boxes are up-to date.
>
> I''m experiencing trouble with networking.
> Dom0 can reach the outside world when no DomU are started. It can also
reach
> the outside world when only one DomU is running.
> The troubles begin when I start the second DomU. At first, this new DomU,
> called DomU2, can''t get outside. (at the time Dom0 and DomU1 are
still
> reachable from outside).
> Once I get connected to DomU2 (console mode, xm console DomU2) and try to
> get outside, I''ll get through after a small amout of time.
Nevertheless,
> this causes Dom0 to stop being reachable from the outside.
> Therefore when my two DomUs are running, there are running fine and I can
> reach them with SSH but Dom0 becomes unreachable. After sometimes it
changes
> Dom0 becomes reachable again and one of the 2 DomUs becomes unreachable
from
> the outside. It is completely random but there''s still one of the
Doms which
> is unreachable. It depends on the one I''m connected to !
> BUT being connected to the console on the server, I can reach each DomU
> (DomU1 and DomU2) from Dom0 or reach Dom0 from each DomUs (DomU1 and DomU2)
> I help myself with some tutorials but can''t get through my
difficulties.
> http://wiki.xensource.com/xenwiki/XenNetworking
> http://doc.fedora-fr.org/wiki/Xen_et_le_réseau
> http://www.shorewall.net/XenMyWay.html  => Xen and the Art of
Consolidation
>
> Nevertheless, I can''t get through my troubles.
>
> Here''s the result of the ifconfig command when everything is
started : DomUs
> + Dom0
> eth0      Link encap:Ethernet  HWaddr 00:21:85:32:CA:8E         inet
> adr:172.20.25.2  Bcast:172.20.25.255  Masque:255.255.255.0
>         adr inet6: fe80::221:85ff:fe32:ca8e/64 Scope:Lien
>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>         RX packets:88446 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:2906 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:0
>         RX bytes:6888620 (6.5 MiB)  TX bytes:189520 (185.0 KiB)
>
> lo        Link encap:Boucle locale         inet adr:127.0.0.1
>  Masque:255.0.0.0
>         adr inet6: ::1/128 Scope:HÃ´te
>         UP LOOPBACK RUNNING  MTU:16436  Metric:1
>         RX packets:34 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:34 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:0
>         RX bytes:7010 (6.8 KiB)  TX bytes:7010 (6.8 KiB)
>
> peth0     Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF         adr inet6:
> fe80::fcff:ffff:feff:ffff/64 Scope:Lien
>         UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
>         RX packets:25871448 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:5396663 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:100
>         RX bytes:31027675382 (28.8 GiB)  TX bytes:434789497 (414.6 MiB)
>         MÃ(c)moire:de340000-de360000
>
> vif0.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF         adr inet6:
> fe80::fcff:ffff:feff:ffff/64 Scope:Lien
>         UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
>         RX packets:2906 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:88446 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:0
>         RX bytes:189520 (185.0 KiB)  TX bytes:6888620 (6.5 MiB)
>
> vif1.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF         adr inet6:
> fe80::fcff:ffff:feff:ffff/64 Scope:Lien
>         UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
>         RX packets:1886 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:86964 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:32
>         RX bytes:127848 (124.8 KiB)  TX bytes:6453003 (6.1 MiB)
>
> vif2.0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF         adr inet6:
> fe80::fcff:ffff:feff:ffff/64 Scope:Lien
>         UP BROADCAST RUNNING NOARP  MTU:1500  Metric:1
>         RX packets:5389130 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:10150353 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:32
>         RX bytes:358810111 (342.1 MiB)  TX bytes:15229333872 (14.1 GiB)
>
> virbr0    Link encap:Ethernet  HWaddr 00:00:00:00:00:00         inet
> adr:192.168.122.1  Bcast:192.168.122.255  Masque:255.255.255.0
>         adr inet6: fe80::200:ff:fe00:0/64 Scope:Lien
>         UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>         RX packets:0 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:44 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:0
>         RX bytes:0 (0.0 b)  TX bytes:8758 (8.5 KiB)
>
> xenbr0    Link encap:Ethernet  HWaddr FE:FF:FF:FF:FF:FF         UP
BROADCAST
> RUNNING NOARP  MTU:1500  Metric:1
>         RX packets:84790 errors:0 dropped:0 overruns:0 frame:0
>         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
>         collisions:0 lg file transmission:0
>         RX bytes:4982000 (4.7 MiB)  TX bytes:0 (0.0 b)
>
> I can''t understand why the MAC addresses of peth0 is different
from the one
> of eth0. vibr0 seems to be useless. These should be the same,
shouldn''t they
> ?
> peth0''s MAC address and xenbr0''s MAC address are the same
which seems
> logical to me. Am I wrong ?
>
> Can anyone help ?
> Any suggestions will be greatly appreciated.
>

What is the output of:

brctl show
ip route list

with 0, 1 and 2 domUs running?

The networking parts of xend-config.sxp and the vif lines in your
domUs might be useful.

Cheers.
Todd

> Kind regards,
>
> --
>
> Stéphane Cesbron
> Responsable Régional Informatique,
> INSERM ADR Grand-Ouest,
> BRETAGNE, PAYS DE LA LOIRE et CENTRE
>
> 63, quai Magellan
> 3ème étage - Hall B
> B.P. 32116
> 44021 Nantes cedex 1
>
> Email : stephane.cesbron@inserm.fr
> Tél : 02.40.20.92.28
> Portable : 06.78.68.76.39
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--
Todd Deshane
http://todddeshane.net
check out our book: http://runningxen.com