elasticsearch/elasticsearch — pull request #6779 by bleskes (2014-07-08 12:25:09+00:00)
Title: [Discovery] verify connect when sending a rejoin cluster request

When a master receives a cluster state from another node, it compares the local cluster state with the one it got. If the local one has a higher version, it sends a JoinClusterRequest to the other master to tell it step down. Because our network layer is asymmetric, we need to make sure we're connected before sending.