Xen users - Nov 2006 - network issue, RHEL4, lack of peth0/peth1 device

Hi! I''m not new to Xen but I''m new to this list. I''m
having a truely bizarre problem with Xen bridged networking at the moment. This
is a new install, on RHEL4. The symptom is that any domU set up simply fails to
talk to anything else. It''s there, and running, and it has an ethernet
device, but there''s never any response.

After digging through the system for a while and comparing it to another system
I have that works, I discovered that the bridge appears to only be partially set
up on boot. Specifically, it''s empty, and the pethX (in my case peth1)
device is missing entirely.

I have dredged through the network-bridge script and run through as much of it
as I can in my head, it *seems* like the situation I''m encountering
should be impossible unless something is failing in an odd manner in the middle
of the script. I can''t play around too extensively, the system is
thousands of miles away from me and has no remote console or friendly hands
nearby.

Has anyone heard of anything like this? I know at least one other person has
encountered it, my symptoms match those described by Greg Cymbalski on Tue, 7
Mar 2006 12:33:24 on this list.

All applicable information follows.

Xen: 3.0.3 RPM version from xensource, kernel 2.6.16.29-xen_3.0.3.0
Dom0: RHEL4.4 fresh install, LVM
Hardware: 2xDual Core Xeon 2ghz, 2gb ram, 250gb SATA (mirrored)
Network: eth1 is the only active (and default) network device

xend-config.sxp:

(xend-http-server yes)
(xend-relocation-server yes)
(xend-port            8000)
(xend-relocation-port 8002)
(xend-address localhost)
(xend-relocation-address ''localhost'')
(xend-relocation-hosts-allow ''^localhost$
^localhost\\.localdomain$'')
(network-script network-bridge)
(vif-script vif-bridge)
(dom0-min-mem 196)
(dom0-cpus 0)

xm_core1:

kernel  = ''/boot/vmlinuz-2.6-xen''
ramdisk = ''/boot/initrd-2.6-xen.img''
memory  = ''1024''
cpus = "0,1"
vcpus = 2
root    = ''/dev/sda2 ro''
disk = [''phy:vg/s1_swap,sda1,w'',
''phy:vg/s1_root,sda2,w'',
''phy:vg/s1_var,sda3,w'',
''phy:vg/s1_home,sda4,w'']
name    = ''core1''
vif  = [ ''ip=XXX.XX.XX.XXX,bridge=xenbr1'' ]
on_poweroff = ''destroy''
on_reboot   = ''restart''
on_crash    = ''restart''

# ip link
1: lo: <LOOPBACK,UP> mtu 16436 qdisc noqueue
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: vif0.0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
3: veth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether 00:00:00:00:00:00 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
5: veth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
6: vif0.2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
7: veth2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
8: vif0.3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether fe:ff:ff:ff:ff:ff brd ff:ff:ff:ff:ff:ff
9: veth3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff
10: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop qlen 1000
    link/ether 00:13:72:f8:2a:b4 brd ff:ff:ff:ff:ff:ff
11: eth1: <BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:13:72:f8:2a:b2 brd ff:ff:ff:ff:ff:ff
12: sit0: <NOARP> mtu 1480 qdisc noop
    link/sit 0.0.0.0 brd 0.0.0.0
13: xenbr1: <BROADCAST,NOARP,UP> mtu 1500 qdisc noqueue
    link/ether 00:00:00:00:00:00 brd ff:ff:ff:ff:ff:ff


#
# Before xm_core1 startup
#

# brctl show
bridge name     bridge id               STP enabled     interfaces
xenbr1          8000.000000000000       no               can''t get port
info: Function not implemented

* The "can''t get port info" message appears to be what
happens when the bridge is empty, when I start up xm-core1 it contains one vif


# iptables -L -v -n
Chain INPUT (policy ACCEPT 46 packets, 3352 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain OUTPUT (policy ACCEPT 27 packets, 3676 bytes)
 pkts bytes target     prot opt in     out     source               destination


#
# After xm_core1 startup
#

# brctl show
bridge name     bridge id               STP enabled     interfaces
xenbr1          8000.feffffffffff       no              vif1.0

# iptables -L -v -n
Chain INPUT (policy ACCEPT 109 packets, 7940 bytes)
 pkts bytes target     prot opt in     out     source               destination

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
 pkts bytes target     prot opt in     out     source               destination
    0     0 ACCEPT     all  --  *      *       XXX.XX.XX.XXX        0.0.0.0/0   
PHYSDEV match --physdev-in vif1.0
    0     0 ACCEPT     udp  --  *      *       0.0.0.0/0            0.0.0.0/0   
PHYSDEV match --physdev-in vif1.0 udp spt:68 dpt:67

Chain OUTPUT (policy ACCEPT 64 packets, 8352 bytes)
 pkts bytes target     prot opt in     out     source               destination

-- 
Richard Clark,
Analysis and Design,
Red Spider Ltd.
(+64) 021 478 219

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