Home > Storage > PowerMax and VMAX > Storage Admin > Persistent Storage for Containerized Applications on Kubernetes with PowerMax SAN Storage > Overview
CSI drivers are applications that implement gRPC services, as described in the CSI specification. They are the glue between the Kubernetes claim for storage and the storage backend.
The CSI Driver for PowerMax has two components:
The controller can run in a high availability mode with multiple instances running in parallel. They run in an active-passive mode, and the coordination to select the active Pod uses a Lease. To identify the active controller (which can be useful if you need to check logs), you can run kubectl get leases -n powermax. The leaseholder is the active controller.