On 29.03.22 04:14, Jakub Kicinski wrote:
> On Mon, 28 Mar 2022 10:14:16 +0200 Alexandra Winter wrote:
>> In case virtual instances are attached to an external network via veth
>> and a bridge, the interface to the external network can be a bond
>> interface. Bonding drivers generate specific events during failover
>> that trigger switch updates. When a veth device is attached to a
>> bridge with a bond interface, we want external switches to learn about
>> the veth devices as well.
>
> Can you please add an ASCII diagram of a setup your trying to describe?
| veth_a2 | veth_b2 | veth_c2 |
------o-----------o----------o------
\ | /
o o o
veth_a1 veth_b1 veth_c1
-------------------------
| bridge |
-------------------------
bond0
/ \
eth0 eth1
In case of failover from eth0 to eth1, the netdev_notifier needs to
be propagated, so e.g. veth_a2 can re-announce its MAC address to the
external hardware attached to eth1.
Does that help?
>
>> Without this patch we have seen cases where recovery after bond
>> failover took an unacceptable amount of time (depending on timeout
>> settings in the network).
>>
>> Due to the symmetric nature of veth special care is required to avoid
>> endless notification loops. Therefore we only notify from a veth
>> bridgeport to a peer that is not a bridgeport.
>>
>> References:
>> Same handling as for macvlan:
>> 4c9912556867 ("macvlan: Support bonding events"
>> and vlan:
>> 4aa5dee4d999 ("net: convert resend IGMP to notifier event")
>
> When sending a single patch change you can put all the information
> in the commit message of the patch, the cover letter is only necessary
> for series of multiple patches.
Thank you, I will do so in v2.
