Dell's REX-Ray, A Storage Orchestrator for Docker, Embraces CSI Specs

Storing data persistently inside Docker containers remains difficult.

A storage orchestrator from Dell Technologies, REX-Ray, hopes to solve that challenge.

Docker containers are great if you want to host “stateless” applications — meaning those that don’t need to store data permanently or otherwise maintain a persistent state.

But for “stateful” apps that require data storage, Docker is more challenging.

Docker offers a feature called Storage Volumes for connecting a containerized application to persistent storage.

However, configuring Storage Volumes is complex and not feasible to do on a large scale without the assistance of automation.

To use containers effectively at scale, developers need a way to automate Storage Volumes configuration or another kind of persistent storage solution for Docker.

REX-Ray, a “Storage Orchestrator” for Docker Containers

This is where REX-Ray comes in.

Dell Technologies’s {code} organization, which develops open source technologies with Dell’s support, announced the 0.10 release of REX-Ray this week.

The developers describe REX-Ray as a “storage orchestrator” for Docker.

The tool automates the process of connecting containerized applications to persistent storage.

REX-Ray supports the storage systems that are commonly used with cloud-native applications, such as NFS and block devices.

Embracing Open Standards for Container Storage

REX-Ray’s developers say that it is the first project to support the Container Storage Interface (CSI), a proposed industry standard.

The CSI proposal is still under discussion and has not been widely endorsed by other organizations in the container ecosystem.

REX-Ray has competition.

Portworx is probably the leading alternative to REX-Ray.

ClusterHQ, a persistent storage company focused on the container space that shut down late last year, left behind Flocker, which lives on as an open source project.

Yet REX-Ray’s approach to persistent container storage is somewhat more “pure-play” than those of other vendors.

REX-Ray wants to advance a community standard.

It’s not building a major commercial offering (at least yet).

At version 0.10, REX-Ray is not yet ready for production.

However, organizations seeking to test it out can grab the current development code from GitHub.

Click here to view a GIF explainer on REX-Ray.