Docker Volume Driver Plugin Models

Docker Volume Plugin opens a flood gate of innovations. In my rough categorization, the following two models summarize current development status.

Model 1


In this model, you’ll find volume drivers directly connected to filesystems. Containers can use the backend filesystems for data persistence. No more magic beyond what the backends can provide.

Model 2


Examples in this model include Flocker, Convoy, RexRay. Value added volume managers virtualize the backend filesystems. They can provide data services such as migration, snapshot, backup, etc.

Historical Perspective

Volume management has been with storage industry for many years. There are tricks to play and requirements to meet. I am sure Docker Volumes see no exception.

Fibre Channel Storage for Kubernetes

11 billion ports of Fibre Channel make Fibre Channel a great story for Kubernetes ecosystem.

This is where I have spent my time in the last couple of days. A Kubernetes prototype using Fibre Channel volume is now available at my github repo.

In the example Pod, the FC target WWN array and LUN number must be provided. A filesystem is re-formatted on the LUN. Multipath is enabled automatically if Kubernetes hosts’ devicemapper works.

Unlike OpenStack, FC SAN Zone Manager support is NOT supported, yet. Consequently, this could mean SAN admins have to make all Kubernetes hosts in the same storage pool. This picture, though, could change in the future.

Since this volume requires hardware setup, end-to-end test is not easy (or even possible?) to write as in other volumes.