Squashed the commits.

Thanks!

It has obviously been an omission, and I can imaging COs would want to use this. Can you leave a link in the comments where this new procedure would be used?

It's expected that statically provisioned group snapshots would use this API to populate information about the individual members of the group snapshot. Today we don't have a good way of getting the necessary information in that case. One hack is to rely on ListSnapshots with a snapshot ID passed in, but many drivers don't support that, due to other challenges related to snapshot listing.

@jdef Here is the KEP: https://github.com/kubernetes/enhancements/pull/5013/files
ListSnapshots API works as well, however, many storage vendors could not support list snapshots due to the performance overhead.
Usually storage vendors do not have a problem supporting GetSnapshot if they want to support volume snapshot or volume group snapshot.

Is there a KEP that describes the use case? Unclear why the list API doesn't work here. James DeFelice

@jdef This proposal seemed pretty uncontroversial to me. Do you want us to wait while you review the KEP before approving?

I think that there are some vendors that can't implement a real List and they're uncomfortable implementing a List that only works in certain cases (like returning a snapshot when the ID is passed in, but returning nothing when no ID is passed in). Even though singleton-List works, it's a kludge compared to a dedicated Get API. I think we've learned that we eventually need Get APIs across the board, and there's little point in trying to avoid adding them.

Last call before I merge this