kube-single-age/utils/data-migrate

0. the namespace will be the namespace for your target application
1. run the application you need
2. wait for its PVs to be created
3. suspend the application: kubectl scale deployment/statefulset/... NAME -n NAMESPACE --replicas=0
4. wait for it to scale down so that the ReadWriteOnce PVs are released (or data-migrate will not be able to mount them)
5. look up the destination PVC name you need: kubectl get pvc NAME -n NAMESPACE
6. put the namespace, source host(node) and dir and destination PVC name to install.yaml
7. install the data-migrate: kubectl delete pod data-migrate -n NAMESPACE --ignore-not-found=true && kubectl apply -f install.yaml
8. run the migration: kubectl exec data-migrate -n NAMESPACE -- cp -a /old/. /new/ or anything you need instead of cp or interactive shell kubectl exec -it data-migrate -n NAMESPACE -- sh (or bash or zsh)
9. validate you have everything migrated: kubectl exec data-migrate -n NAMESPACE -- ls -laR /new
10. uninstall the data-migrate: kubectl delete pod data-migrate -n NAMESPACE
11. resume the application back: kubectl scale deployment/statefulset/... NAME -n NAMESPACE --replicas=1