patroni builds upon etcd and (optionally) haproxy, two rather mature pieces of infrastructure (which can both be made HA on their own if SPOFs are to be avoided).
I understand where you are coming from, but having this kind of multi-server-who-is-master knowledge baked into Postgres itself will surely take another couple of releases, if it will be included at all.
Probably BDR (bi-directional replication, master-master like logical replication) will be there first, but whether the question is whether it will help a lot for local scale-out workloads (as opposed to glueing two datacenters together and allow transactions on both sides).
Re:New Features Coming in PostgreSQL 10
by xyzzy_plugh on Monday April 10, 2017 @06:08AM
(#14077219)
Number 2 is the only point I see merit in. With respect to 3, isn't that an argument against increasing the complexity of postgresql?
1. Minimize cognitive load by minimizing the number of things you have to learn.
2. Minimize deployment complexity and dependencies.
3. Complexity is just evil I'm general. Linear increases in complexity result in exponential increases in bugs, vulnerabilities, and failure modes. It's just combinatorics.