Comment 5 for bug 1402763

Things appear to be somewhat random; however setting the multicast_querier flag to 1 resulted in all my clustered spring back to life:

for i in `seq 0 10`; do juju ssh $i "echo -n 1 | sudo tee /sys/devices/virtual/net/juju-br0/bridge/multicast_querier"; done

Juju creates a bridge where this is not enabled by default.