STP does not work properly when creating bridge inside container

1

Hello,

I have a container with multiple interfaces. I am creating a network bridge between them using the brctl command and enabling stp on that bridge. However, when I now create a network loop inside my network, the network gets flooded with traffic and is effectively unusable.

I noticed that the bridge does not accept any other node as root. When manually setting the priority however, other nodes do accept the bridge inside the container as root.

When I try the same thing otside of a container, everything works as intended and the bridge accepts other nodes as root.

Could there be any reason why stp messages are somehow disregarded inside a container? Or is there some configuration that has to be set for stp to properly work?

2

Can you post some example config and commands to show your setup so I can try and recreate?

3

You should be able to recreate the Issue using the following steps:
-Create a container with two interfaces, in this case eth0 and eth1
-Install bridge-utils inside the container
-type the following commands:

brctl addbr bridge
brctl addif bridge eth0
brctl addif bridge eth1
brctl stp bridge on
ifconfig bridge up

-now connect eth0 or eth1 to a network with STP already working
-when typing

brctl showstp bridge

the field “designated root” will always be the same as “bridge id” even when the bridge inside the container is not the root bridge

4

How are you connecting eth0 and eth1 to an external network? What NIC type are you using?

5

The interfaces are physically connected to the external network, the nictype is physical.

6

For anyone encountering this problem in the future:
The workaround we ended up using is to use openvswitch instead of bridge-utils.
For this solution to work however openvswitch has to be installed in both, the Container and the Host.

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