[ovs-dev] Multiple OVS vswitchd controlling same kernel path?

Tim Rozet trozet at redhat.com
Wed Mar 25 14:08:14 UTC 2020

Hi All,
I've run into this question several times, and several folks have different
opinions. I was hoping we could resolve it. The question centers around
having multiple OVS vswitchd instances in different netns on the same host
using kernel data path. In the past several folks have told me this does
not work, because there will be potential conflicts in the kernel data
path, or each OVS may flush the kernel path flows without regard for
what another OVS has programmed. In contrast, some other folks have told me
this should work perfectly fine as each OVS has is using its own DPID and
there should be 0 conflicts.

One use case around this is being able to use Kubernetes In Docker (KIND),
where we are running multiple Docker containers acting as "nodes" with ovs
containers inside them, to simulate a large k8s deployment on a single
host. Antrea has added support for using netdev mode and claims that kernel
data path with multiple OVS will not work:

Would appreciate if anyone has any insights on this.

Tim Rozet
Red Hat CTO Networking Team

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