CoreOS - A modern Linux distro for running clusters

CoreOS is a powerful Linux distribution built to make large, scalable deployments on varied infrastructure simple to manage. Based on a build of Chrome OS, CoreOS maintains a lightweight host system and uses Docker containers for all applications. This system provides process isolation and also allows applications to be moved throughout a cluster easily.

To manage these clusters, CoreOS uses a globally distributed key-value store called etcd to pass configuration data between nodes. This component is also the platform for service discovery, allowing applications to be dynamically configured based on the information available through the shared resource.

In order to schedule and manage applications across the entirety of the cluster, a tool called fleet is used. Fleet serves as a cluster-wide init system that can be used to manage processes across the entire cluster. This makes it easy to configure highly available applications and manage the cluster from a single point. It does this by tying into each individual node's systemd init system.

The general design of a CoreOS installation is geared towards clustering and containerization.