Add GetSnapshot RPC

[xing-yang]

What type of PR is this?
feature

What this PR does / why we need it:
This PR adds a GetSnapshot RPC

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce an API-breaking change?:

Adds GetSnapshot RPC.

[bswartz]

/lgtm

[nixpanic]

Looks good to me, thanks! You probably want to squash the commits into one before it gets merged?

[xing-yang]

Squashed the commits.

[nixpanic]

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?

[bswartz]

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]

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

…

On Mon, Apr 28, 2025, 1:12 PM Ben Swartzlander ***@***.***> wrote: *bswartz* left a comment (container-storage-interface/spec#586) <#586 (comment)> 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. — Reply to this email directly, view it on GitHub <#586 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAR5KLGNAPRZ6P7SBB5IDOD23ZOOBAVCNFSM6AAAAAB3JY3BXCVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDQMZVHEZDSNZYGY> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[xing-yang]

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.