Error mounting imported snapshot

[psincraian]

What did you do?

I have a mongodb installed in a droplet, and I want to migrate it to k8s. The mongodb droplet has a volume attached to it where I have all the data. I created a snapshot of the volume and I followed the import snapshot guide to import the data to the mongo pod. The pod with a new volume without using snapshot works as expected, but when I want to import the snapshot to a new PV then I get an error.

What did you expect to happen?

The importing of a snapshot and mounting to the PV to work. But I get the following error

Events:
  Type     Reason                  Age                From                     Message
  ----     ------                  ----               ----                     -------
  Normal   Scheduled               34s                default-scheduler        Successfully assigned default/task-pv-pod to pepy-cluster-mmlco
  Normal   SuccessfulAttachVolume  32s                attachdetach-controller  AttachVolume.Attach succeeded for volume "pvc-84afc954-100d-446a-b102-5cccd9a6faa3"
  Warning  FailedMount             12s (x6 over 28s)  kubelet                  MountVolume.MountDevice failed for volume "pvc-84afc954-100d-446a-b102-5cccd9a6faa3" : rpc error: code = Internal desc = mounting failed: exit status 255 cmd: 'mount -t ext4 /dev/disk/by-id/scsi-0DO_Volume_pvc-84afc954-100d-446a-b102-5cccd9a6faa3 /var/lib/kubelet/plugins/kubernetes.io/csi/dobs.csi.digitalocean.com/fe73301729091014250d5739d47348212dfea5e54285731b4f37b36f8138ae32/globalmount' output: "mount: mounting /dev/disk/by-id/scsi-0DO_Volume_pvc-84afc954-100d-446a-b102-5cccd9a6faa3 on /var/lib/kubelet/plugins/kubernetes.io/csi/dobs.csi.digitalocean.com/fe73301729091014250d5739d47348212dfea5e54285731b4f37b36f8138ae32/globalmount failed: Invalid argument\n"

Configuration (MUST fill this out):

Log dump

Files

nginx.yml

apiVersion: v1
kind: Pod
metadata:
  name: task-pv-pod
spec:
  volumes:
    - name: storage
      persistentVolumeClaim:
        claimName: pepy-mongo-pvc
  containers:
    - name: task-pv-container
      image: nginx
      ports:
        - containerPort: 80
          name: "http-server"
      volumeMounts:
        - mountPath: "/"
          name: storage

pvc.yml

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pepy-mongo-pvc
spec:
  dataSource:
    name: snapshot-manual
    kind: VolumeSnapshot
    apiGroup: snapshot.storage.k8s.io
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 30Gi

snapshot.yml

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
  name: snapshot-manual
spec:
  volumeSnapshotClassName: do-block-storage
  source:
    volumeSnapshotContentName: snapshotcontent-manual

snapshotcontent.yml

apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotContent
metadata:
  name: snapshotcontent-manual
spec:
  deletionPolicy: Retain
  driver: dobs.csi.digitalocean.com
  source:
    snapshotHandle: 3a1f36bb-6841-11ed-ba59-0a58ac1456fb
  volumeSnapshotRef:
    name: snapshot-manual
    namespace: default

• Kubernetes Version: Kubernetes 1.24.4-do.0

• Cloud provider/framework version, if applicable (such as Rancher): N/A

[timoreimann]

👋

The failure seems to be with mounting. Is the original volume an ext4 file system as well?

[psincraian]

Hey @timoreimann

I think you are right, the file system is not ext4 🤦‍♂️

Thanks for your help! 😊

[timoreimann]

mount error messages can be pretty hard to make sense out of. Glad we figured it out. 👍

[psincraian]

Hey @timoreimann, sorry to bother you, but how can I specify the file system type of the snapshot? I tried to find in the docs but I cannot see it 🤔

[timoreimann]

Hey @psincraian 👋 you need to specify a StorageClass which has the desired file system configured. FWIW, in DOKS we pre-provide a number of popular StorageClass configurations next to the standard one. If none fits you, you can create a new one and reference it in your object(s).