DockerCon StorageOS (now Ondat) is a UK-based startup offering simple and automated block storage to stateless containers, giving them state and the means to run databases and other applications that need enterprise-class storage functionality without the concomitant complexity, rigidity and cost.
It runs as a container in a Linux system and provides plug-ins for other containers to use that give them easy, programmatic access to stateful storage services.
Read more at The Register.