Etcd username and password for Docker overlay networking

We are trying to use Docker overlay networking without using Swarm. We plan to use an etcd key-value store and wish to connect to it using an etcd username/password and take advantage of the role-based access control that etcd provides.

I came across the following commit in libkv that adds username, password support to its etcd interface

  1. In which version of Docker Engine will this be available ?

  2. How can the etcd username and password be supplied to Docker Engine so that it uses these credentials to connect to etcd ?

Would appreciate any additional insights and/or suggestions (e.g. if this feature can somehow be used with available versions)