How to pre-populate a ReadOnlyMany Persistent Volume

Question

I am trying to create a deployment in GKE that uses multiple replicas. I have some static data which I want to have available in every pod. This data will not be updated, no write is required.

I decided to use a PV with a corresponding PVC with the ReadOnlyMany storage class. The thing is, I do not know how to actually transfer my data to the volume - since it is read-only. I tried using

gcloud compute scp /local/path instance:/remote/path

but of course, I get a permission error. I then tried creating a new PV via the console. I attached it to a VM with

gcloud compute instances attach disk

mounted and formatted the disk, transfered my data, unmounted the disk, detached it from the VM and finally created a PVC following the documentation. I changed the storage class to ReadOnlyMany, the only difference.

But still, when I'm trying to scale my deployment to more than one replicas I get an error saying the disk is already attached to another node.

So, how can I create a volume that is to be used in ReadOnlyMany and populate the disk with data? Or is there a better approach since no write is required?

Thanks in advance

Answer 1

Worked for me. Have you specified readOnly: true when using persistent volume claim in the Pod template?

volumes:
- name: my-volume
  persistentVolumeClaim:
    claimName: my-readonly-pvc
    readOnly: true

See details here https://cloud.google.com/kubernetes-engine/docs/how-to/persistent-volumes/readonlymany-disks