Merge pull request #43418 from chrishenzie/readwriteoncepod-ga-blog

Feature blog for ReadWriteOncePod GA graduation

Author: k8s-ci-robot

content/en/blog/_posts/2023-12-18-read-write-once-pod-access-mode-ga.md

@@ -0,0 +1,99 @@
+---
+layout: blog
+title: "Kubernetes 1.29: Single Pod Access Mode for PersistentVolumes Graduates to Stable"
+date: 2023-12-18
+slug: read-write-once-pod-access-mode-ga
+---
+
+**Author:** Chris Henzie (Google)
+
+With the release of Kubernetes v1.29, the `ReadWriteOncePod` volume access mode
+has graduated to general availability: it's part of Kubernetes' stable API. In
+this blog post, I'll take a closer look at this access mode and what it does.
+
+## What is `ReadWriteOncePod`?
+
+`ReadWriteOncePod` is an access mode for
+[PersistentVolumes](/docs/concepts/storage/persistent-volumes/#persistent-volumes) (PVs)
+and [PersistentVolumeClaims](/docs/concepts/storage/persistent-volumes/#persistentvolumeclaims) (PVCs)
+introduced in Kubernetes v1.22. 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.
+
+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.
+
+## How can I start using `ReadWriteOncePod`?
+
+The `ReadWriteOncePod` volume access mode is available by default in Kubernetes
+versions v1.27 and beyond. In Kubernetes v1.29 and later, the Kubernetes API
+always recognizes this access mode.
+
+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:
+
+- [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)
+
+To start using `ReadWriteOncePod`, you need to create a PVC with the
+`ReadWriteOncePod` access mode:
+
+```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
+applied.
+
+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 methods 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.