Add description on Conflict on installing VolumePopulator CR for `V…

…olumeSnapshotLink` across CSI drivers

keps/sig-storage/3294-provision-volumes-from-cross-namespace-snapshots/README.md

@@ -91,6 +91,7 @@ tags, and then generate with `hack/update-toc.sh`.
   - [Risks and Mitigations](#risks-and-mitigations)
     - [Secret Handling](#secret-handling)
     - [Security](#security)
+    - [Conflict on installing <code>VolumePopulator</code> CR for <code>VolumeSnapshotLink</code> across CSI drivers](#conflict-on-installing--cr-for--across-csi-drivers)
 - [Design Details](#design-details)
   - [Example flow of how this proposal works](#example-flow-of-how-this-proposal-works)
   - [API](#api)
@@ -310,6 +311,15 @@ In addition, there will be cases that `ReferenceGrant` may be created/deleted/re
     If all the processes succeed without any error, it succeeds even the `ReferenceGrant` is deleted in the middle of the processes.
     If any errors happend in the processes and the controller retries, it may detect that there is no `ReferenceGrant` . Then, it won't use the `VolumeSnapshot` until the `ReferenceGrant` that allows the access is re-created.
 
+#### Conflict on installing `VolumePopulator` CR for `VolumeSnapshotLink` across CSI drivers
+
+This feature requires installing VolumePopulator` CR for `VolumeSnapshotLink` and is enabled per CSI driver basis.
+Therefore, on enabling this feature for each CSI driver, it is expected that `VolumePopulator` CR for `VolumeSnapshotLink` is created before each CSI driver installation.
+As a result, there may be a conflict in creating it for each driver, if there are any differences in their definitions, like alpha API and beta API.
+
+To avoid this issue, it should be avoided to manage VolumePopulator` CR for `VolumeSnapshotLink` in each CSI driver's repository.
+It should be managed in another single repository and the same CR should be used per cluster basis.
+
 ## Design Details
 
 <!--
@@ -424,7 +434,7 @@ As a reference implementation, only (a) will be implemented in the community.
 
 Regardless of the implementation,
 - `VolumeSnapshotLink` CRD and `ReferenceGrant` CRD must exist in the cluster before the populator is deployed.
-- `VolumePopulator` CRD to allow popluating from `VolumeSnapshotLink` CRD needs to be created to enable this feature, as AnyVolumeDataSource feature defines. The `VolumePopulator` CRD needed for this feature will be as follows:
+- `VolumePopulator` CR to allow popluating from `VolumeSnapshotLink` CRD needs to be created to enable this feature, as AnyVolumeDataSource feature defines. The `VolumePopulator` CR needed for this feature will be as follows:
 ```yaml
 kind: VolumePopulator
 apiVersion: populator.storage.k8s.io/v1beta1