Ref: kubernetes/kops#2858 (comment)
So DNS ... one of our challenges. Here is some background information and what I understand.
In order to do cool stuff like HA control plane (masters) and have a functional rolling update of a cluster, you need a way for Etcd and Nodes to find the stuff it needs to find. The option that is generic i.e. works on multiple platforms, of course, is DNS. But DNS can be a bit of a pain, and for instance, in AWS China, there is not route53 DNS. Also what about running in GCE, when you do not want to use a public DNS domain? As far as I know, a user cannot have a private domain hosted by GCE.
So enter gossip. As mentioned above gossip is a communication pattern which allows a distributed system to maintain eventual consistency. Gossip is actually a very good pattern for eventual consistency. Many systems like Weave and Cassandra use gossip.
Quite simply instead of using DNS, a kops clusters can perform lookups using gossip. Here is an example. During the creation of a kops cluster or a rolling update of a cluster, Etcd nodes need to discover each other. Instead of using Route53 for DNS, the hostnames are now updated via protokube container running gossip.
Trade offs. At this point using gossip is new, and is not hardened by users breaking it. So that is exactly what we need the user base to do, is use it, break it for us, so we can make kops great! Also without DNS, you do not get stuff like a DNS name for the API endpoint.