How to store the configuration of a distributed application?

Question

NoSQL

I'm thinking about choosing a dynamic configuration storage solution for a large distributed application.
Now we have a homemade solution that rsync scatters json files across nodes and a watcher on each node that updates local databases and updates the process configuration if it can be done at runtime.
The input is something like this:
- 50+ physical nodes
- 1000+ containers (docker)
- 3000+ json configuration files
- 10M+ keys in these files
- 500Mb+ disk space (json)
I want to find a reliable KV solution with the following properties:
- eventual consistency
- the ability to subscribe to change a key or a group of keys by key prefix from the application
- get the key must happen locally (replicas will be on each physical node) - designed
for the fastest possible reading (replication speed is not critical)
I suppose to look at consul, etcd, zookeeper, couchDB. If someone has thoughts on this topic and valuable advice, please share :)