Date:	Tue, 3 Jan 2012 23:23:48 +0000
From:	"Wyborny, Carolyn" <carolyn.wyborny@...el.com>
To:	Chris Boot <bootc@...tc.net>,
	Nicolas de Pesloüan 
	<nicolas.2p.debian@...il.com>
CC:	netdev <netdev@...r.kernel.org>,
	"e1000-devel@...ts.sourceforge.net" 
	<e1000-devel@...ts.sourceforge.net>
Subject: RE: igb + balance-rr + bridge + IPv6 = no go without promiscuous
 mode



>-----Original Message-----
>From: netdev-owner@...r.kernel.org [mailto:netdev-owner@...r.kernel.org]
>On Behalf Of Chris Boot
>Sent: Tuesday, December 27, 2011 1:53 PM
>To: Nicolas de Pesloüan
>Cc: netdev
>Subject: Re: igb + balance-rr + bridge + IPv6 = no go without
>promiscuous mode
>
>On 23/12/2011 10:56, Chris Boot wrote:
>> On 23/12/2011 10:48, Nicolas de Pesloüan wrote:
>>> [ Forwarded to netdev, because two previous e-mail erroneously sent
>in
>>> HTML ]
>>>
>>> Le 23/12/2011 11:15, Chris Boot a écrit :
>>>> On 23/12/2011 09:52, Nicolas de Pesloüan wrote:
>>>>>
>>>>>
>>>>> Le 23 déc. 2011 10:42, "Chris Boot" <bootc@...tc.net
>>>>> <mailto:bootc@...tc.net>> a écrit :
>>>>> >
>>>>> > Hi folks,
>>>>> >
>>>>> > As per Eric Dumazet and Dave Miller, I'm opening up a separate
>>>>> thread on this issue.
>>>>> >
>>>>> > I have two identical servers in a cluster for running KVM virtual
>>>>> machines. They each have a
>>>>> single connection to the Internet (irrelevant for this) and two
>>>>> gigabit connections between each
>>>>> other for cluster replication, etc... These two connections are in
>a
>>>>> balance-rr bonded connection,
>>>>> which is itself member of a bridge that the VMs attach to. I'm
>>>>> running v3.2-rc6-140-gb9e26df on
>>>>> Debian Wheezy.
>>>>> >
>>>>> > When the bridge is brought up, IPv4 works fine but IPv6 does not.
>>>>> I can use neither the
>>>>> automatic link-local on the brid ge nor the static global address I
>>>>> assign. Neither machine can
>>>>> perform neighbour discovery over the link until I put the bond
>>>>> members (eth0 and eth1) into
>>>>> promiscuous mode. I can do this either with tcpdump or 'ip link set
>>>>> dev ethX promisc on' and this
>>>>> is enough to make the link spring to life.
>>>>>
>>>>> For as far as I remember, setting bond0 to promisc should set the
>>>>> bonding member to promisc too.
>>>>> And inserting bond0 into br0 should set bond0 to promisc... So
>>>>> everything should be in promisc
>>>>> mode anyway... but you shoudn't have to do it by hand.
>>>>>
>>>>
>>>> Sorry, I should have added that I tried this. Setting bond0 or br0
>to
>>>> promisc has no effect. I
>>>> discovered this by running tcpdump on br0 first, then bond0, then
>>>> eventually each bond member in
>>>> turn. Only at the last stage did things jump to life.
>>>>
>>>>> >
>>>>> > This cluster is not currently live so I can easily test patches
>>>>> and various configurations.
>>>>>
>>>>> Can you try to remove the bonding part, connecting eth0 and eth1
>>>>> directly to br0 and see if it
>>>>> works better? (This is a test ony. I perfectly understand that you
>>>>> would loose balance-rr in this
>>>>> setup.)
>>>>>
>>>>
>>>> Good call. Let's see.
>>>>
>>>> I took br0 and bond0 apart, took eth0 and eth1 out of enforced
>>>> promisc mode, then manually built a
>>>> br0 with eth0 in only so I didn't cause a network loop. Adding eth0
>>>> to br0 did not make it go into
>>>> promisc mode, but IPv6 does work over this setup. I also made sure
>ip
>>>> -6 neigh was empty on both
>>>> machines before I started.
>>>>
>>>> I then decided to try the test with just the bond0 in balance-rr
>>>> mode. Once again I took everything
>>>> down and ensured no promisc mode and no ip -6 neigh. I noticed bond0
>>>> wasn't getting a link-local and
>>>> I found out for some reason
>>>> /proc/sys/net/ipv6/conf/bond0/disable_ipv6 was set on both servers
>so I
>>>> set it to 0. That brought things to life.
>>>>
>>>> So then I put it all back together again and it didn't work. I once
>>>> again noticed disable_ipv6 was
>>>> set on the bond0 interfaces, now part of the bridge. Toggling this
>on
>>>> the _bond_ interface made
>>>> things work again.
>>>>
>>>> What's setting disable_ipv6? Should this be having an impact if the
>>>> port is part of a bridge?
>>
>> Hmm, as a further update... I brought up my VMs on the bridge with
>> disable_ipv6 turned off. The VMs on one host couldn't see what was on
>> the other side of the bridge (on the other server) until I turned
>> promisc back on manually. So it's not entirely disable_ipv6's fault.
>
>Hi,
>
>I don't want this to get lost around the Christmas break, so I'm just
>resending it. I'm still seeing the same behaviour as before.
>
> From above:
>
>>>>> For as far as I remember, setting bond0 to promisc should set the
>>>>> bonding member to promisc too.
>>>>> And inserting bond0 into br0 should set bond0 to promisc... So
>>>>> everything should be in promisc
>>>>> mode anyway... but you shoudn't have to do it by hand.
>
>This definitely doesn't happen, at least according to 'ip link show |
>grep PROMISC'.
>
>Chris
>
>--
>Chris Boot
>bootc@...tc.net
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Sorry for the delay in responding.  I'm not sure what is going on here and I'm not our bonding expert who is still out on holidays.  However, we'll try to reproduce this.  When I get some more advice, I may be asking for some more data.

Thanks,

Carolyn
Carolyn Wyborny
Linux Development
LAN Access Division
Intel Corporation

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