Guest post by Evan Powell, CEO at MayaData

Last year we published a blog with a good amount of coaching and feedback from the CNCF team that set out to define the Container Attached Storage (CAS) approach.  As a reminder, we tend to include OpenEBS of course as well as solutions that have similar architectures such as the proprietary PortWorx and StorageOS into the CAS category.

Now that OpenEBS has been contributed to the CNCF as a Sandbox project as an open source example of the CAS approach (as of May 14th 2019), I thought it timely to update this overview of the category.   

Last year’s category-defining blog built on a vision of our approach that I had shared some years before at the Storage Developer Conference and which Jeffry Molanus, MayaData’s CTO has discussed in more depth at FOSDEM (Free and Open source Software Developers’ European Meeting) and elsewhere including demonstrating soon to be available software breaking the million IOPS barrier:

Diagram showing NVMe, NBD, and iSCSi performance

As a quick review:

Key attributes of CAS include:

Key benefits of CAS:

And the key drivers – why is it possible and even necessary now?

If you are interested in a hopefully humorous view of the history of storage in three slides, please take a look at this GIF-filled presentation:

Season 3 Money GIF - Find & Share on GIPHY
One does not simply create new a storage system meme

Data on what we have learned in the last year:  

The momentum MayaData has and other CAS solution provides are experiencing validates that the Container Attached Storage approach makes a lot of sense for many users.  

We have learned a lot about these deployment patterns and common workloads, some of which I summarize here.  The following data is from a survey of OpenEBS users however the patterns are similar for CAS more broadly – keeping in mind that OpenEBS is open source and especially lightweight so it may skew slightly more towards cloud deployments for example.  

What Kubernetes?

Bar chart showing percentage of OpenEBS user survey towards Kubernetes choice
  1.  Similarly, when asked what workloads they are running on OpenEBS, we again see a great diversity of answers:
Bar chart showing percentage of OpenEBS user survey towards workloads users run on OpenEBS

What we have found is similar to what I think everyone that has worked in storage has found over the years – workloads and solutions pull storage along.  

Over the last year, we have seen opportunities for collaboration with other CAS solution providers as well.  As an example, we collaborated with Portworx in supporting and improving WeaveScope. The MayaData team contributed extensions to the WeaveScope project to add visibility of PVCs and PVs and underlying storage and Portworx engineers provided feedback and insight into use cases.  The software is of course upstream in WeaveScope itself and then we also offer a free monitoring and management solution called MayaOnline for community members as well that incorporates this code.

While CAS approaches allow Kubernetes to orchestrate the data along with, the workloads – the natural question that is often asked is essentially “Dude, where’s my data?”  As you can see WeaveScope and MayaOnline provide an up to date answer to that and related questions:

Screenshot showing MayaOnline topology page


Thank you all for your feedback and support over the last couple of years since we first open sourced OpenEBS in early 2017 and since we helped to define the Container Attached Category in the Spring of 2018.  We increasingly hear and see the CAS category used by commentators and “thought leaders” – which is great. The idea of an additive and truly Kubernetes native solution for data services just makes too much sense.  

After all – what is good for the goose (the applications and workloads themselves) is good for the gander (in this case all manner of infrastructure, including storage services).  Even though addressing cloud lock-in could impact the primary source of revenues for clouds, we still, on the whole, see support in the Kubernetes and cloud-native community for the CAS pattern.  

We are getting closer than ever to the openness and agility we need for our data to keep up with our applications.  Thanks again for your interest in the CAS pattern. Please keep in touch with your feedback, use cases, and insights.