Core Kubernetes

7 Pod storage and the CSI

This chapter covers

• Introducing the virtual filesystem (VFS)
• Exploring Kubernetes in-tree and out-of-tree storage providers
• Running dynamic storage in a kind cluster with multiple containers
• Defining the Container Storage Interface (CSI)

Storage is complex, and this book won’t cover all the storage types available to the modern app developer. Instead, we’ll start with a concrete problem to solve: our Pod needs to store a file. The file needs to persist between container restarts, and it needs to be schedulable to new nodes in our cluster. In this case, the default baked-in storage volumes that we’ve already covered in this book won’t “cut the mustard”:

• Our Pod can’t rely on hostPath because the node itself may not ...