Importing an existing block storage to your Managed Kubernetes cluster

Last updated on: February 14, 2025

This should be done very carefully and at your own risk, as there is a possibility of data loss if something goes wrong.

Importing a block storage volume as a Persistent Volume Claim to your Managed Kubernetes cluster requires following steps:

Take a backup of your volume!
Grant storage permissions to your volume for the CSI sub-account
Create PV and PVC objects that match your existing volume
Create a test pod and verify the volume mount works

Prerequisites

kubectl installed
Block storage volume in the same zone as your Managed Kubernetes cluster
Backups taken prior to starting the operation
Main account access to UpCloud's Hub (hub.upcloud.com)

Grant device permissions

Access your Managed Kubernetes cluster. CSI driver is run using sub-account credentials.

Get the username of your CSI user:

$ kubectl -n kube-system get secrets upcloud -o yaml -o jsonpath='{.data.username}'|base64 -d
```xml

### Grant device permissions using Hub

Go to the permission section of the UpCloud Control Panel and grant CSI sub-account for permission to access the storage volume you want to use in Managed Kubernetes.

### Grant device permissions using API

Use following permission JSON object to set permission using `POST` request to `/1.3/permission/grant` API endpoint:

```json
{
  "permission": {
    "options": {},
    "target_identifier": "<storage_uuid>",
    "target_type": "storage",
    "user": "<csi_subaccount_username>"
  }
}

Create a Persistent Volume

Create the following file:

apiVersion: v1
kind: PersistentVolume
metadata:
  annotations:
    pv.kubernetes.io/provisioned-by: storage.csi.upcloud.com
  name: PV_NAME
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: STORAGE_SIZE
  claimRef:
    apiVersion: v1
    kind: PersistentVolumeClaim
    name: PVC_NAME
    namespace: NAMESPACE_NAME
  csi:
    driver: storage.csi.upcloud.com
    volumeHandle: VOLUME_UUID
  persistentVolumeReclaimPolicy: Retain
  storageClassName: upcloud-block-storage-maxiops
  volumeMode: Filesystem

Replace the following fields:

PV_NAME: Name for the PV object you are about to create. This is referenced in the next step.
STORAGE_SIZE: Size of the storage volume (for example 10Gi)
PVC_NAME: Name for the PVC object you will create on the next step.
NAMESPACE_NAME: Namespace for the PVC object
VOLUME_UUID: UUID of the underlying storage volume you are importing

Then apply:

kubectl apply -f pv.yaml

Create a Persistent Volume Claim

Next, create the following file:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: PVC_NAME
spec:
  storageClassName: upcloud-block-storage-maxiops
  volumeName: PV_NAME
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: STORAGE_SIZE
```bash

Replace `PVC_NAME`, `PV_NAME` and `STORAGE_SIZE` with the same values as in the previous step.

Then apply:

```sh
kubectl apply -f pvc.yaml

Create a test pod and mount the storage