etcd is a distributed key-value store designed to reliably and quickly preserve and provide access to critical data. It enables reliable distributed coordination through distributed locking, leader elections, and write barriers. An etcd cluster is intended for high availability and permanent data storage and retrieval.
The easiest way to get started using etcd as a distributed key-value store is to set up a local cluster.
Administrators who need a fault-tolerant etcd cluster for either development or production should begin with a cluster on multiple machines.
To learn more about the concepts and internals behind etcd, read the following pages: