GlusterFS is already containerized
Gluster exists as a containerized implementation on top of Kubernetes, including management support from Kubernetes Storage API. The idea is to re-use the same infrastructure orchestration layer as the actual application uses - so eventually storage is deployed as another function next to the application stack. Thus no separate scheduling / high availability / orchestration mechanism needs to be implemented for storage and accessing data this way is potentially very fast - as it does not have to cross several layers of hypervisors and hyper-convergence.
I believe this will be the most elegant form of containerized storage.