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Hands-on Lab·Certified Kubernetes Administrator

CSI Drivers

Kubernetes has no storage code of its own. A CSI driver is a plugin plus a set of sidecars that translate Kubernetes objects into gRPC calls, and installing one without a StorageClass gives you a driver nothing can use.

Storage Guide 72 of 103 Advanced

Written against the versions above. The reference hostpath driver is for testing only, never production. What it demonstrates about the CSI architecture applies to every driver.

The hostpath driver runs as a single StatefulSet, so everything it provisions is pinned to whichever node that Pod is on.
Server NameIP AddressOSRolesCPURAMHDD
CKA1001192.168.0.175Ubuntu 26.04 LTSControl Plane Node2 Core4 GB50 GB
CKA1001-NODE01192.168.0.176Ubuntu 26.04 LTSWorker Node2 Core4 GB50 GB
CKA1001-NODE02192.168.0.177Ubuntu 26.04 LTSWorker Node2 Core4 GB50 GB
CKA1001-NODE03192.168.0.178Ubuntu 26.04 LTSWorker Node2 Core4 GB50 GB

Before you start

  1. What the cluster has before, and why local-path is not CSI

  2. Snapshot support is an add-on, not a feature

  3. A driver is a plugin plus sidecars

  4. The trap: a driver with no StorageClass

  5. With a class, the whole chain works

  6. Expansion, and the resize that waits for a restart

Official sources