That's a great point. But doesn't this make it mandatory for the applications to use Go? It would have been more useful if there was a REST interface for leader election.
There's some more information (and a sidecar pod prebaked) at http://blog.kubernetes.io/2016/01/simple-leader-election-wit...
// This implementation does not guarantee that only one client is acting as a // leader (a.k.a. fencing). A client observes timestamps captured locally to // infer the state of the leader election. Thus the implementation is tolerant // to arbitrary clock skew, but is not tolerant to arbitrary clock skew rate.