github.com/ghodss/etcd@v0.3.1-0.20140417172404-cc329bfa55cb/Documentation/production-ready.md

ectd is being used successfully by many companies in production. It is,
however, under active development and systems like etcd are difficult to get
correct. If you are comfortable with bleeding-edge software please use etcd and
provide us with the feedback and testing young software needs.

When the etcd team feels confident removing this warning we will release etcd
1.0.