[CentOS-virt] xenbr0 isn't created anymore

Thu Mar 27 18:37:05 UTC 2008
Kai Schaetzl <maillists at conactive.com>

Ross S. W. Walker wrote on Thu, 27 Mar 2008 12:35:17 -0400:

> Ok, well I wanted to make sure xend is running at the right runlevels
> and see if there is anything else weird set to start that shouldn't.

It's set to the standard runlevels 2-5

> 
> I also see you are having other problems, with portmap, maybe the two
> are related and they both sound like it has to do with the network.

Interestingly, I got portmap fixed by way of trying to fix the xenbr 
problem. But  don't know how it got fixed, you'll see in on the other 
list.

> 
> Did you do anything on the network side around the time of the failure?

Definitely, no. I disabled the RH-firewall and a few services like cups 
that I don't need. No changes to any network interfaces. From comparing 
the boot log messages the network-bridge doesn't ever seem to run now.

> 
> Maybe there is an interface definition for virbr0 that is left around
> but since libvirt is disabled, a bridge isn't activated for it to
> apply to?

If I startup libvirtd only virbr0 gets created, nothing else. I enabled 
libvirtd at boot time again, but this doesn't help. The difference is only 
the following:

Mar 27 17:57:48 mambo kernel: Bridge firewalling registered
Mar 27 17:57:48 mambo kernel: ip_tables: (C) 2000-2006 Netfilter Core Team
Mar 27 17:57:49 mambo kernel: Netfilter messages via NETLINK v0.30.
Mar 27 17:57:49 mambo kernel: ip_conntrack version 2.4 (8192 buckets, 
65536 max) - 228 bytes per conntrack

Mar 27 17:57:50 mambo dnsmasq[3105]: started, version 2.39 cachesize 150
<more dnsmasq stuff skipped>

so, the problem cannot be connected to libvirtd being present or not.

This is how it looks if everything goes well during boot:

Feb 24 17:31:14 mambo xenstored: Checking store ...
Feb 24 17:31:14 mambo xenstored: Checking store complete.
Feb 24 17:31:14 mambo xenstored: Checking store ...
Feb 24 17:31:14 mambo xenstored: Checking store complete.
Feb 24 17:31:15 mambo dhcpd: receive_packet failed on eth0: Network is 
down

<it seems eth0 is taken down here, so network-bridge can run>

Feb 24 17:31:15 mambo kernel: device vif0.0 entered promiscuous mode
Feb 24 17:31:15 mambo kernel: xenbr0: port 1(vif0.0) entering learning 
state
Feb 24 17:31:15 mambo kernel: peth0: link up, 100Mbps, full-duplex, lpa 
0x45E1
Feb 24 17:31:15 mambo kernel: xenbr0: topology change detected, 
propagating
Feb 24 17:31:15 mambo kernel: xenbr0: port 1(vif0.0) entering forwarding 
state
Feb 24 17:31:15 mambo kernel: peth0: Promiscuous mode enabled.
Feb 24 17:31:15 mambo kernel: device peth0 entered promiscuous mode
Feb 24 17:31:16 mambo kernel: xenbr0: port 2(peth0) entering learning 
state
Feb 24 17:31:16 mambo kernel: xenbr0: topology change detected, 
propagating
Feb 24 17:31:16 mambo kernel: xenbr0: port 2(peth0) entering forwarding 
state

Feb 24 17:31:21 mambo kernel: tap tap-1-51712: 2 getting info
Feb 24 17:37:09 mambo kernel: tap tap-2-51712: 2 getting info
Feb 24 17:37:09 mambo kernel: device vif2.0 entered promiscuous mode
Feb 24 17:37:09 mambo kernel: ADDRCONF(NETDEV_UP): vif2.0: link is not 
ready
Feb 24 17:37:13 mambo kernel: blktap: ring-ref 8, event-channel 8, 
protocol 1 (x86_32-abi)
Feb 24 17:37:35 mambo kernel: ADDRCONF(NETDEV_CHANGE): vif2.0: link 
becomes ready
Feb 24 17:37:35 mambo kernel: xenbr0: port 3(vif2.0) entering learning 
state
Feb 24 17:37:35 mambo kernel: xenbr0: topology change detected, 
propagating
Feb 24 17:37:35 mambo kernel: xenbr0: port 3(vif2.0) entering forwarding 
state

and this seems to be the first time where it started failing:
Mar 24 20:35:11 mambo logger: /etc/xen/scripts/vif-bridge: Could not find 
bridge device xenbr0
Mar 24 20:35:16 mambo kernel: blkback: ring-ref 8, event-channel 6, 
protocol 1 (x86_32-abi)
Mar 24 20:35:16 mambo logger: /etc/xen/scripts/vif-bridge: Could not find 
bridge device xenbr0
Mar 24 20:35:18 mambo logger: /etc/xen/scripts/vif-bridge: Could not find 
bridge device xenbr0
Mar 24 20:35:23 mambo kernel: blkback: ring-ref 8, event-channel 7, 
protocol 1 (x86_32-abi)
Mar 24 20:35:23 mambo logger: /etc/xen/scripts/vif-bridge: Could not find 
bridge device xenbr0
Mar 24 20:35:24 mambo kernel: tap tap-3-51712: 2 getting info
Mar 24 20:35:24 mambo udevd-event[3800]: udev_node_mknod: mknod
(/dev/xen/blktap1, 020600, 253, 1) failed: File exists
Mar 24 20:35:25 mambo logger: /etc/xen/scripts/vif-bridge: Could not find 
bridge device xenbr0
Mar 24 20:35:29 mambo kernel: blktap: ring-ref 8, event-channel 6, 
protocol 1 (x86_32-abi)
Mar 24 20:35:29 mambo logger: /etc/xen/scripts/vif-bridge: Could not find 
bridge device xenbr0

(the blkback/blktap stuff seems to be related, but I don't know what it 
means.)

The latter happens when there are DomUs to restore, without them it's just 
the four lines about xenstored. Any up notices for xenbr0 etc. are 
completely missing.



Kai

-- 
Kai Schätzl, Berlin, Germany
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