Add Support for Snapshots

[maennchen]

https://kubernetes-csi.github.io/docs/external-snapshotter.html

[maennchen]

For both snapshots & volume content source, files have to be synced via gsutil rsync (please mention better ideas :) )

I would recommend that CreateSnapshot and also the restoring of a snapshot / from another volume (#13) starts a Job with a gsutil container that actually does the copying. The function would block until the call succeeded.

[ofek]

Does the Go lib support https://cloud.google.com/storage/docs/moving-buckets#rest-copy-objects?

[maennchen]

@ofek One at a time, yes....

[ofek]

Should we include gsutil even though it would be large? I'm not a k8s expert but starting a job seems hacky. Is it?

[maennchen]

@ofek I don't think that this would be hacky... I think that's a perfect application of K8S.

I would create a separate image only doing that and not package it into the same container.

[ofek]

I mean, is it normal for a container to start another container?

[maennchen]

For Operators: yes

[ofek]

Hmm interesting, okay then 😄

[maennchen]

Better Idea:

Instead of waiting minutes to copy small amounts of data via gsutil, a TransferJob can be created & executed via API. This should be fairly fast and needs no compute power.

https://cloud.google.com/storage-transfer/docs/reference/rest/v1/transferJobs/create

Credit @jeremyzahner

[ofek]

Oh very neat. We'd just need to document how to add the required scope to a service account.

[maennchen]

Tracked via #47