[PVE-User] Strange problem on bridge after upgrade to proxmox 7

[Richard Lucassen]

On Thu, 19 May 2022 19:58:09 +0200
Simone Piccardi via pve-user <pve-user at lists.proxmox.com> wrote:

> Hi, I have a very strange networking problem on a Proxmox server, 
> emerged after upgrading from 6.4 to 7.

I have no idea if this can have something to do with it, but not a very
long time ago I had two Dell R210 servers connected through a simple
failover bond0. The issue I found was that somehow these bond0 devices
on two *different* servers got the *same* fixed MAC address. After some
searching I stumbled upon this:

https://blog.sigterm.se/posts/a-bonding-exercise/

I had some discussion afterward with Patrik and I ended up in adding a
fixed MAC address in the /etc/network/interfaces stanza, e.g.:

hwaddress ether 4a:89:66:60:e4:97

I just want to notify this phenomena because you can get the most weird
behaviour if you have two devices having the same MAC. I tested loading
the bonding on some workstations:

modprobe -v bonding
ip link show bond0

and see what address it gets, it depends on this value:
cat /sys/class/net/bond0/addr_assign_type
which me be different from host to host.

To remove the module:
modprobe -rv bonding

I had no time to dive deeper into this matter, I just worked around it
by adding the "hwaddress ether" in the bond0 stanza. This works fine.

My 2cts,

R.

-- 
richard lucassen
http://contact.xaq.nl/