Kubernetes Storage Concepts

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Internal

Overview

Kubernetes has a mature and feature-rich subsystem called the persistent volume subsystem. Regardless of where it comes from, storage is exposed to the Kubernetes cluster in the form of a volume.

Storage Providers

Storage is exposed to a Kubernetes cluster by storage providers.

The Kubernetes persistent volume subsystem supports, among others:

Each storage provider has its own plugin that handles the details of exposing the storage to the Kubernetes cluster.

Storage Plugin

The terms "storage plugin" and "provisioner" are used interchangeably.

Old plugins used to be. Newer plugins are based on the Container Storage Interface (CSI).

Container Storage Interface (CSI)

Container Storage Interface (CSI) is an open standard that provides a clean interface for storage plugins.

API Resources

PersistentVolume (PV)

PersistentVolumeClaim (PVC)

StorageClass (SC)

Volume

Secrets may be exposed as files in dedicated volumes mounted in the pod.

Volume Type

Dynamic Volume Provisioning

Dynamic volume provisioner https://kubernetes.io/docs/concepts/storage/dynamic-provisioning/

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