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Feature blog for ReadWriteOncePod GA graduation
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content/en/blog/_posts/2023-10-10-read-write-once-pod-access-mode-ga.md
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| --- | ||
| layout: blog | ||
| title: "Kubernetes 1.29: Single Pod Access Mode for PersistentVolumes Graduates to GA/Stable" | ||
| date: 2023-10-10 | ||
| slug: read-write-once-pod-access-mode-ga | ||
| --- | ||
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| **Author:** Chris Henzie (Google) | ||
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| With the release of Kubernetes 1.29 the ReadWriteOncePod feature has graduated | ||
| to GA. In this blog post, we'll take a closer look at this feature and what it | ||
| does. | ||
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| ## What is ReadWriteOncePod? | ||
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| ReadWriteOncePod is a new access mode for | ||
| [PersistentVolumes](/docs/concepts/storage/persistent-volumes/#persistent-volumes) (PVs) | ||
| and [PersistentVolumeClaims](/docs/concepts/storage/persistent-volumes/#persistentvolumeclaims) (PVCs) | ||
| introduced in Kubernetes 1.22. This access mode enables you to restrict volume | ||
| access to a single pod in the cluster, ensuring that only one pod can write to | ||
| the volume at a time. This can be particularly useful for stateful workloads | ||
| that require single-writer access to storage. | ||
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| For more context on access modes and how ReadWriteOncePod works read | ||
| [What are access modes and why are they important?](/blog/2021/09/13/read-write-once-pod-access-mode-alpha/#what-are-access-modes-and-why-are-they-important) | ||
| in the _Introducing Single Pod Access Mode for PersistentVolumes_ article from 2021. | ||
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| ## How can I start using ReadWriteOncePod? | ||
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| ReadWriteOncePod is enabled by default in cluster versions 1.27 and beyond. | ||
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| Note that ReadWriteOncePod is | ||
| [only supported for CSI volumes](/docs/concepts/storage/persistent-volumes/#access-modes). | ||
| and before using this feature, you will need to update the following | ||
| [CSI sidecars](https://kubernetes-csi.github.io/docs/sidecar-containers.html) | ||
| to these versions or greater: | ||
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| - [csi-provisioner:v3.0.0+](https://github.com/kubernetes-csi/external-provisioner/releases/tag/v3.0.0) | ||
| - [csi-attacher:v3.3.0+](https://github.com/kubernetes-csi/external-attacher/releases/tag/v3.3.0) | ||
| - [csi-resizer:v1.3.0+](https://github.com/kubernetes-csi/external-resizer/releases/tag/v1.3.0) | ||
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| To start using ReadWriteOncePod, you need to create a PVC with the ReadWriteOncePod access mode: | ||
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| ```yaml | ||
| kind: PersistentVolumeClaim | ||
| apiVersion: v1 | ||
| metadata: | ||
| name: single-writer-only | ||
| spec: | ||
| accessModes: | ||
| - ReadWriteOncePod # Allows only a single pod to access single-writer-only. | ||
| resources: | ||
| requests: | ||
| storage: 1Gi | ||
| ``` | ||
| If your storage plugin supports | ||
| [Dynamic provisioning](/docs/concepts/storage/dynamic-provisioning/), then | ||
| new PersistentVolumes will be created with the ReadWriteOncePod access mode set. | ||
| Read [Migrating existing PersistentVolumes](/blog/2021/09/13/read-write-once-pod-access-mode-alpha/#migrating-existing-persistentvolumes) | ||
| for details on migrating existing volumes to use ReadWriteOncePod. | ||
| ## How can I learn more? | ||
| Please see the blog posts [alpha](/blog/2021/09/13/read-write-once-pod-access-mode-alpha), | ||
| [beta](/blog/2023/04/20/read-write-once-pod-access-mode-beta), and | ||
| [KEP-2485](https://github.com/kubernetes/enhancements/blob/master/keps/sig-storage/2485-read-write-once-pod-pv-access-mode/README.md) | ||
| for more details on the ReadWriteOncePod access mode and motivations for CSI | ||
| spec changes. | ||
| ## How do I get involved? | ||
| The [Kubernetes #csi Slack channel](https://kubernetes.slack.com/messages/csi) | ||
| and any of the standard | ||
| [SIG Storage communication channels](https://github.com/kubernetes/community/blob/master/sig-storage/README.md#contact) | ||
| are great mediums to reach out to the SIG Storage and the CSI teams. | ||
| Special thanks to the following people whose thoughtful reviews and feedback helped shape this feature: | ||
| * Abdullah Gharaibeh (ahg-g) | ||
| * Aldo Culquicondor (alculquicondor) | ||
| * Antonio Ojea (aojea) | ||
| * David Eads (deads2k) | ||
| * Jan Šafránek (jsafrane) | ||
| * Joe Betz (jpbetz) | ||
| * Kante Yin (kerthcet) | ||
| * Michelle Au (msau42) | ||
| * Tim Bannister (sftim) | ||
| * Xing Yang (xing-yang) | ||
| If you’re interested in getting involved with the design and development of CSI | ||
| or any part of the Kubernetes storage system, join the | ||
| [Kubernetes Storage Special Interest Group](https://github.com/kubernetes/community/tree/master/sig-storage) (SIG). | ||
| We’re rapidly growing and always welcome new contributors. |