Libnetwork Overlay driver and Multicast


over the last days I have experimented with getting a quick way to quickly scale up Elasticsearch and Hazelcast. With the help of multicast I have managed to get it work and it works great on a single host.

Yesterday I installed the 1.9-dev version to start experiment with multihost networking. After some initial setup issues I can ping from one container to another one on a different host just as expected.

But multicast doesn’t seem to traverse the vxlan link which becomes a problem with the solution above.

I have checked with tcpdump in the overlay network namespace and multicast traffic is blocked somewhere. Is this a missing feature or have I missed some undocumented setting somewhere? (Multicast is enabled on all interfaces)