ReadWriteMany (RWX) Example with NFS

In certain scenarios, multiple pods need to read from and write to the same storage location concurrently. Kubernetes handles these requirements using ReadWriteMany (RWX) access modes. While most common cloud block storage solutions (like EBS or GCE PD) do not support RWX, NFS (Network File System) is a widely used option to enable this.

This section demonstrates how to set up shared storage using NFS with RWX access in Kubernetes.

🎯 When to Use RWX Volumes

Use ReadWriteMany (RWX) volumes when: - Multiple pods need to read/write files to the same storage directory - You’re running web server clusters sharing static content - Microservices exchange data files or logs through a shared directory - Data pipelines need to store temporary or intermediate files accessible by multiple jobs - You need to perform log aggregation in a central location

🛠️ StorageClass for NFS

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: nfs-sc
provisioner: example.com/nfs  # Replace this with your NFS CSI driver name
parameters:
  archiveOnDelete: "false"  # Optional: defines what happens to storage after PVC deletion
  • StorageClass acts as a storage type template.
  • The provisioner specifies the external storage plugin (in this case, an NFS CSI driver).
  • archiveOnDelete is an example parameter (depending on the provisioner implementation).

📦 PersistentVolumeClaim (PVC) Requesting RWX Access

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: shared-pvc
spec:
  accessModes:
    - ReadWriteMany  # RWX access mode
  resources:
    requests:
      storage: 5Gi
  storageClassName: nfs-sc
  • Requests 5Gi of shared storage
  • Specifies ReadWriteMany (RWX) so multiple pods can mount and write concurrently
  • Uses the previously defined nfs-sc StorageClass

🐳 Pod Using the Shared Volume

apiVersion: v1
kind: Pod
metadata:
  name: frontend-pod
spec:
  containers:
    - name: frontend
      image: nginx
      volumeMounts:
        - mountPath: "/usr/share/nginx/html"
          name: shared-storage
  volumes:
    - name: shared-storage
      persistentVolumeClaim:
        claimName: shared-pvc
  • Deploys a Pod running NGINX
  • Mounts the shared-pvc at /usr/share/nginx/html
  • If multiple pods use the same PVC with RWX access, they can all read/write files in the same directory

📝 Why RWX matters:

Without RWX support: - Pods can’t safely share storage (with RWO, only one pod can mount the volume as read-write) - NFS (or other RWX-providing systems) unlocks this shared access pattern

✅ Summary

This example demonstrates how to: - Provision a StorageClass for NFS - Create a PersistentVolumeClaim (PVC) requesting RWX access - Deploy a pod that mounts and uses the shared volume

By using NFS with ReadWriteMany access, multiple pods can share, read, and write to the same persistent storage concurrently — enabling reliable and scalable shared data use cases in Kubernetes.

Example Use Cases:

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