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CSI-S3

CSI-S3 is a Container Storage Interface driver that mounts an S3-compatible bucket as a Kubernetes persistent volume. Pods read and write the bucket as if it were a regular volume.

Install via Helm​

helm repo add yandex-cloud https://yandex-cloud.github.io/k8s-csi-s3/charts/
helm install csi-s3 yandex-cloud/csi-s3 \
  --namespace kube-system \
  --set secret.endpoint=https://s3.filebase.io \
  --set secret.accessKey=YOUR_FILEBASE_KEY \
  --set secret.secretKey=YOUR_FILEBASE_SECRET \
  --set storageClass.region=auto

Define a StorageClass​

storage-class.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: csi-s3
provisioner: ru.yandex.s3.csi
parameters:
  mounter: geesefs
  bucket: my-csi-bucket
  endpoint: https://s3.filebase.io
  region: auto
  csi.storage.k8s.io/provisioner-secret-name: csi-s3-secret
  csi.storage.k8s.io/provisioner-secret-namespace: kube-system
  csi.storage.k8s.io/node-publish-secret-name: csi-s3-secret
  csi.storage.k8s.io/node-publish-secret-namespace: kube-system
kubectl apply -f storage-class.yaml

PersistentVolumeClaim​

pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: csi-s3-pvc
spec:
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi
  storageClassName: csi-s3

Use in a pod​

apiVersion: apps/v1
kind: Deployment
metadata:
  name: example
spec:
  replicas: 1
  selector:
    matchLabels:
      app: example
  template:
    metadata:
      labels:
        app: example
    spec:
      containers:
        - name: app
          image: my-app:latest
          volumeMounts:
            - name: filebase
              mountPath: /data
      volumes:
        - name: filebase
          persistentVolumeClaim:
            claimName: csi-s3-pvc

The /data directory inside the container is now backed by Filebase.

Performance notes​

CSI-S3 (via geesefs) is convenient but slower than block storage. Use for:

  • Sharing files between pods (ReadWriteMany).
  • Workloads with small / occasional I/O.

Avoid for:

  • Database persistence (use a real PV).
  • Hot-path read workloads (use object storage directly via the S3 API).

What's next​