Recently, I have been working with, and learning a lot about the new distributed operating system, CoreOS. It is really interesting and makes managing micro-service architectures, quite a bit easier than manually SSHing into each machine and dealing every node individually. At the heart of CoreOS sits ETCD, a distributed key / value store. Internally CoreOS uses it for node discovery, communication and orchestration. Unlike other key / value stores, ETCD feels a bit more like a file system with directories and files. A directory can contain multiple directories and files where a file can contain a single value. For example, you might store the name of the environment as /company/metadata/environment = staging. It is a data hierarchy, which means it

onfiguration is an important piece to not only making your application deployable, but flexible and accommodating to change. We can't predict how an application will need to accept configuration between a local setup, build servers, staging and production. More over, if any of those things were to change, large parts of the application would need to change how it handles configuration. Some systems prefer files, some prefer environment variables some prefer command line arguments.

The Basics

A production ready application should be able to collect configuration from multiple sources and reconcile them into a single entity that is referenced throughout the application. We're going to walk through a sensible way to do this. The first thing we need to