Network connectivity in XEN domU's broken

This document (3725904) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 10 SP1
SUSE Linux Enterprise Server 10

Situation

Networking on the virtual machine host/domain 0 works, but there is no network connectivity to any of the guests/domain U's.
The output of "ip address show" looks normal, except that the peth0 interface is missing.
The peth0, vif0.0 and potential vifx.y for the domU's are missing in the network bridge.

t3:~ # brctl show
bridge name bridge id STP enabled interfaces
xenbr0 8000.000000000000 no

The output of ifconfig also looks normal except the missing peth0 :

# ifconfig
eth0 Link encap:Ethernet HWaddr 00:0E:0C:D7:F7:79
inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::20e:cff:fed7:f779/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:728 errors:0 dropped:0 overruns:0 frame:0
TX packets:708 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:133059 (129.9 Kb) TX bytes:119950 (117.1 Kb)
Base address:0xbc00 Memory:ff7e0000-ff800000

eth0:extr Link encap:Ethernet HWaddr 00:0E:0C:D7:F7:79
inet addr:192.168.0.4 Bcast:192.168.0.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
Base address:0xbc00 Memory:ff7e0000-ff800000

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:333 errors:0 dropped:0 overruns:0 frame:0
TX packets:333 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:25427 (24.8 Kb) TX bytes:25427 (24.8 Kb)

xenbr0 Link encap:Ethernet HWaddr 00:00:00:00:00:00
inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 b) TX bytes:64 (64.0 b)

/var/log/messages does not directly show any errors, but the normal messages concerning peth0 like
Oct 10 13:12:54 t3 kernel: xenbr0: port 2(peth0) entering learning state
Oct 10 13:12:54 t3 kernel: xenbr0: topology change detected, propagating
Oct 10 13:12:54 t3 kernel: xenbr0: port 2(peth0) entering forwarding state
are missing.

Resolution

Removing the additional/secondary/virtual IP address from the physical interface fixes the problem.

Boot the physical host in the normal (non-xen) kernel
Start YaST | Network card | remove the additional address
Boot up with the kenel-xen again.

It is currently not clear if it is supported to have secondary IP address on physical interfaces, but it should apparently be avoided.

In the additional notes section of this TID, the working setup of the above configuration is documented for reference.

Additional Information

t3:~ # brctl show
bridge name bridge id STP enabled interfaces
xenbr0 8000.feffffffffff no vif0.0
peth0
vif3.0

t3:~ # ip a
1: lo: mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2:peth0: mtu 1500 qdisc pfifo_fast qlen 1000
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
inet6 fe80::fcff:ffff:feff:ffff/64 scope link
valid_lft forever preferred_lft forever
3: sit0: mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
4: vif0.0: mtu 1500 qdisc noqueue
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
inet6 fe80::fcff:ffff:feff:ffff/64 scope link
valid_lft forever preferred_lft forever
5: eth0: mtu 1500 qdisc noqueue
link/ether 00:0e:0c:d7:f7:79 brd ff:ff:ff:ff:ff:ff
inet 192.168.0.3/24 brd 192.168.0.255 scope global eth0
inet6 fe80::20e:cff:fed7:f779/64 scope link
valid_lft forever preferred_lft forever
6: vif0.1: mtu 1500 qdisc noop
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
7: veth1: mtu 1500 qdisc noop
link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
8: vif0.2: mtu 1500 qdisc noop
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
9: veth2: mtu 1500 qdisc noop
link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
10: vif0.3: mtu 1500 qdisc noop
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
11: veth3: mtu 1500 qdisc noop
link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
12: xenbr0: mtu 1500 qdisc noqueue
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
inet6 fe80::200:ff:fe00:0/64 scope link
valid_lft forever preferred_lft forever
15:vif3.0: mtu 1500 qdisc pfifo_fast qlen 32
link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
inet6 fe80::fcff:ffff:feff:ffff/64 scope link
valid_lft forever preferred_lft forever

t3:~ # ifconfig
eth0 Link encap:Ethernet HWaddr 00:0E:0C:D7:F7:79
inet addr:192.168.0.3 Bcast:192.168.0.255 Mask:255.255.255.0
inet6 addr: fe80::20e:cff:fed7:f779/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:817603 errors:0 dropped:0 overruns:0 frame:0
TX packets:831789 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:350176807 (333.9 Mb) TX bytes:2280767951 (2175.1 Mb)

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:604253 errors:0 dropped:0 overruns:0 frame:0
TX packets:604253 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:4252850186 (4055.8 Mb) TX bytes:4252850186 (4055.8 Mb)

peth0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:794805 errors:0 dropped:0 overruns:0 frame:0
TX packets:1752595 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:363760259 (346.9 Mb) TX bytes:2344548173 (2235.9 Mb)
Base address:0xbc00 Memory:ff7e0000-ff800000

vif0.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:831789 errors:0 dropped:0 overruns:0 frame:0
TX packets:817603 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:2280767951 (2175.1 Mb) TX bytes:350176807 (333.9 Mb)

vif3.0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::fcff:ffff:feff:ffff/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:8991 errors:0 dropped:0 overruns:0 frame:0
TX packets:14629 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:32
RX bytes:3313138 (3.1 Mb) TX bytes:10920734 (10.4 Mb)

xenbr0 Link encap:Ethernet HWaddr FE:FF:FF:FF:FF:FF
inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
UP BROADCAST RUNNING NOARP MTU:1500 Metric:1
RX packets:3702 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:869204 (848.8 Kb) TX bytes:64 (64.0 b)

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