Persistent Volumes & Storage Claims

By default, container filesystems are ephemeral. To store research inputs, beamline raw data, and trained model weights, you must create a PersistentVolumeClaim (PVC).

1. Creating a CephFS PersistentVolumeClaim

CephFS provides a POSIX-compliant distributed filesystem that supports ReadWriteMany (RWX), allowing hundreds of pods to read and write to the same volume simultaneously.

Create cephfs-claim.yaml:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: lab-shared-data-pvc
  namespace: sci-myproject
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: cephfs-sc
  resources:
    requests:
      storage: 500Gi

Apply the claim:

kubectl apply -f cephfs-claim.yaml
kubectl get pvc -n sci-myproject

---

2. Mounting PVC into a Pod

apiVersion: v1
kind: Pod
metadata:
  name: analysis-worker
  namespace: sci-myproject
spec:
  containers:
    - name: app
      image: python:3.11-slim
      command: ["bash", "-c", "echo 'Experiment data logged' >> /mnt/shared/results.log && sleep 3600"]
      volumeMounts:
        - name: dataset-mount
          mountPath: /mnt/shared
  volumes:
    - name: dataset-mount
      persistentVolumeClaim:
        claimName: lab-shared-data-pvc