Yeah, the HA information was buried/non-existent in the docs until recently, I guess. We also ran into issues when replacing the master, b/c the kubelets where fixed to an ip and the nodes' configuration was basically immutable (provisioned by cloud-config).

What worked for us: Accessing the the master by DNS and putting etcd on a persistent volume. This way we're able to replace the master within a DNS records ttl. As the api server is not a hard requirement for the workload, this is HA enough for us.