Kubernetes Storage Concepts: Difference between revisions

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Each storage provider has its own [[#Storage_Plugin|plugin]] that handles the details of exposing the storage to the Kubernetes cluster.
Each storage provider has its own [[#Storage_Plugin|plugin]] that handles the details of exposing the storage to the Kubernetes cluster.


=Storage Plugin=
=<span id='Storage_Plugin'></span>Storage Plugins=


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

Revision as of 01:59, 10 December 2019

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 Plugins

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

Old storage plugins used to be implemented as part of the main Kubernetes code tree (in-tree), which raised a series of problems, such as that all had to be open-source and their release cycle was tied to the Kubernetes release cycle.

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 and abstracts the internal Kubernetes storage details.

API Resources

The persistent volume subsystem consists of the following three primitives that allow applications to consume storage:

PersistentVolume (PV)

PersistentVolumeClaim (PVC)

A persistent volume claim is similar to a ticket that authorizes a pod to use a certain persistent volume.

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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