Data mover --- node selection by storage class

[Lyndon-Li]

Case 1:

• 2 PVCs, 2 SCs and 2 nodes
• PVC1 uses SC1, PVC2 uses SC2
• SC1 connects to Storage1, SC2 connects to Storage2
• Node1 connects to Storage1 only, Node2 connects to Storage2 only

For the current node-selection feature, data mover has no way to back up the pod and its PVCs successfully, since the backupPods are scheduled either to Node1 or Node2. However, the correct behavior should be backupPod1 for PVC1 goes to Node1 and backupPod2 for PVC2 goes to Node2

[reasonerjt]

I have some doubt about the use-case, if no node-selector is chosen for the backup pod, the pod should be scheduled to the node where the PV can be mounted.
Let's do some investigation to clarify before prioritizing it.

[Lyndon-Li]

As the result of further tests, data mover could work without node-selection in this case.
However, the node-selection feature doesn't work. Since the current node-selection can only specify a list of nodes(e.g., Node1, Node2) for all backupPods, it has no way to tell BackupPod1 to go to Node1 and BackupPod2 to go to Node2