KEP-3314: updated to reflect the latest state

[carlbraganza]

Updated the KEP with relevant changes in the CSI spec and the external snapshot metadata sidecar repository.

[k8s-ci-robot]

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[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: carlbraganza
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[xing-yang]

/ok-to-test

[kaovilai]

Is there any consideration to how backup application could delete the underlying snapshot handle from storage infra or is that left to the storage infra application outside the scope of backup application responsibility?

[carlbraganza]

No. In discussions in the WG meeting we decided that this issue is beyond the scope of the spec.

That would be something between the backup application and the storage infrastructure. The spec does not require support for 0 snapshot retention to exist; this change merely allows CBT to be used in such a circumstance.

In practical terms, in the only supported case that I'm aware of (VMware), and I believe there is no need to "delete" the previous snapshot handle, because it is just a tag in the disk file metadata.