Kubernetes - how to download a PersistentVolume's content

Question

I have a test executor Pod in K8s cluster created through helm, which asks for a dynamically created PersistentVolume where it stores the test results.

Now I would like to get the contents of this volume. It seems quite natural thing to do. I would expect some kubectl download pv <id>. But I can't google up anything.

How can I get the contents of a PersistentVolume?

I am in AWS EKS; so AWS API is also an option. Also I can access ECR so perhaps I could somehow store it as an image and download?

Or, in general, I am looking for a way to transfer a directory, can be even in an archive. But It should be after the container finished and doesn't run anymore.

Answer 1

I can think about two options to fulfill your needs:

1. Create a pod with the PV attached to it and use kubectl cp to copy the contents wherever you need. You could for example use a PodSpec similar to the following:

apiVersion: v1
kind: Pod
metadata:
  name: dataaccess
spec:
  containers:
  - name: alpine
    image: alpine:latest
    command: ['sleep', 'infinity']
    volumeMounts:
    - name: mypvc
      mountPath: /data
  volumes:
  - name: mypvc
    persistentVolumeClaim:
      claimName: mypvc

Please note that mypvc should be the name of the PersistentVolumeClaim that is bound to the PV you want to copy data from.

Once the pod is running, you can run something like below to copy the data from any machine that has kubectl configured to connect to your cluster:

kubectl cp dataaccess:/data data/

2. Mount the PV's EBS volume in an EC2 instance and copy the data from there. This case is less simple to explain in detail because it needs a little more context about what you're trying to achieve.