CSI: Container Storage Interface in Depth

A PVC sits in Pending for five minutes. The StorageClass exists, the CSI driver pods show Running, but nothing is provisioning. Is the external-provisioner sidecar failing to watch PVCs? A missing RBAC rule preventing PV creation? The wrong volumeBindingMode waiting for a pod that hasn't been scheduled yet? Without understanding how CSI components communicate, you're guessing. With it, you check three specific things and find the problem.

The Container Storage Interface (CSI) replaced Kubernetes's in-tree volume plugins, all deprecated since v1.19 and removed by v1.27. Every modern storage integration ships as a CSI driver. The CKA tests StorageClass configuration, dynamic provisioning, and PV/PVC lifecycle across both the "Cluster Architecture" domain (25%) and the "Storage" domain (10%). All of it runs through CSI.