There are two motivations for this change:
(1) CSI plugins are soon going to support volume expansion. For such
plugins, admission controller doesn't know whether the plugins are
capabale of supporting volume expansion or not.
(2) Currently, admission controller rejects PVC updates for in-tree plugins
that don't support volume expansion (e.g., NFS, iSCSI). This change allows
external controllers to expand volumes similar to how external provisioners
operate.
- we now provide clear message to user what to do when cloudprovider resizing is finished
and file system resizing is needed.
- add a event when resizing is successful.
- Use Patch for updating PVCs in both kubelet and controller-manager
- Extract updating pvc util function in one place.
- Only update resize conditions on progress
