Merge pull request kubernetes#36 from huffmanca/csi-snapshot

Add CSI Snapshot support.

storage/csi-snapshot.md

@@ -0,0 +1,106 @@
+---
+title: CSI Snapshots
+authors:
+  - "@chuffman"
+reviewers:
+  - "@gnufied”
+  - “@jsafrane”
+approvers:
+  - "@..."
+creation-date: 2019-09-05
+last-updated: 2019-09-25
+status: provisional
+see-also:
+replaces:
+superseded-by:
+---
+
+# csi-snapshots
+
+## Release Signoff Checklist
+
+- [ ] Enhancement is `implementable`
+- [ ] Design details are appropriately documented from clear requirements
+- [ ] Test plan is defined
+- [ ] Graduation criteria for dev preview, tech preview, GA
+- [ ] User-facing documentation is created in [openshift/docs]
+
+## Summary
+
+We want to include the upstream CSI Snapshot feature in OpenShift.
+
+## Motivation
+
+* This feature has been requested by both the OCS and CNV teams.
+* Snapshotting is an incredibly useful function when it comes to system changes in development areas, as it allows rapid rollback to preview dev versions.
+* Container development benefits from filesystems that provide snapshot functionality.
+
+### Goals
+
+* Rebase the downstream csi-external-snapshotter and csi-external-provisioner images off of the upstream images based on Kubernetes 1.16.
+
+* Package and ship a downstream image of the this sidecar.
+
+### Non-Goals
+
+## Proposal
+
+This feature has already been implemented upstream, and is described in https://github.com/kubernetes/enhancements/blob/master/keps/sig-storage/20190709-csi-snapshot.md . It is currently documented upstream at https://kubernetes.io/docs/concepts/storage/volume-snapshots/ .
+
+We will be releasing the `external-snapshotter` sidecar image to enable CSI Snapshot support in OCP as Developer Preview only. This sidecar can be used by internal teams, such as CNV or OCS, for their drivers.
+
+### User Stories [optional]
+
+#### Story 1
+
+As an OCS developer, I want to release the `csi-external-snapshotter` sidecar image so that users can utilize volume snapshots.
+
+#### Story 2
+
+### Implementation Details/Notes/Constraints [optional]
+
+This feature has already been implemented upstream. Therefore, this feature requires a Kubernetes rebase of 1.15 or later.
+
+### Risks and Mitigations
+
+* Kubernetes 1.15+ rebase
+
+## Design Details
+
+No design is needed, as this feature has already been implemented upstream. The upstream design was discussed under https://github.com/kubernetes/enhancements/blob/master/keps/sig-storage/20190709-csi-snapshot.md.
+
+### Test Plan
+
+We’ll want the e2e tests to run using CSI sidecars shipped as part of OCP. There is ongoing progress in the following links regarding testing OCP CSI sidecars:
+
+* https://github.com/openshift/origin/pull/23560
+* https://jira.coreos.com/browse/STOR-223
+Tests for this sidecar are currently defined upstream at https://github.com/kubernetes-csi/external-snapshotter/tree/master/pkg/controller .
+
+### Graduation Criteria
+
+##### Dev Preview -> Tech Preview
+
+* Unit and e2e tests implemented.
+* Update snapshot CRDs to v1beta1 and enable VolumeSnapshotDataSource feature gate by default. The feature must also be at least v1beta1 upstream, and have a strong indication that it will be made GA in a reasonable time frame with a compatible API.
+
+##### Tech Preview -> GA
+
+* Feature deployed in production and have gone through at least one K8s upgrade.
+* Feature must be GA in Kubernetes.
+
+##### Removing a deprecated feature
+
+### Upgrade / Downgrade Strategy
+
+### Version Skew Strategy
+
+## Implementation History
+
+## Drawbacks
+
+## Alternatives
+
+## Infrastructure Needed [optional]
+
+None. The csi-external-snapshotter repository will be updated to include this feature.