Changes

Consistent and highly-available key value store. Used for backing store for all cluster data. https://etcd.io/docs/ [http://play.etcd.io/install Play with etcd]. github: https://github.com/etcd-io/etcdlabs[https://github.com/etcd-io/etcd/blob/master/Documentation/op-guide/hardware.md#example-hardware-configurations Sizing]