In-tree Storage Plugin to CSI Migration - vSphere Design Doc

Table of Contents

• Summary
  • New Feature Gates
• Design Details
  • Prerequisite testing updates
  • Unit tests
  • Integration tests
  • e2e tests
• Production Readiness Review Questionnaire
• Implementation History

Summary

This document present as a vendor specific KEP for the parent KEP CSI Migration

This inherits all the contents from its parent KEP. It will introduce two new feature gates to be used as as described in its parent KEP. For all other contents, please refer to the parent KEP.

New Feature Gates

• CSIMigrationvSphere
  • As describe in CSI Migration, when this feature flag && the CSIMigration is enabled at the same time, all operations related to the in-tree volume plugin kubernetes.io/vsphere-volume will be redirect to use the corresponding CSI driver. From a user perspective, nothing will be noticed.
• InTreePluginvSphereUnregister
  • This flag technically is not part of CSI Migration design. But it happens to be related and helps with CSI Migration. The name speaks for itself, when this flag is enabled, kubernetes will not register the kubernetes.io/vsphere-volume as one of the in-tree storage plugin provisioners. This flag standalone can work out of CSI Migration features.
  • However, when all InTreePluginvSphereUnregister, CSIMigrationvSphere and CSIMigration feature flags are enabled at the same time. The kube-controller-manager will skip the feature flag checking on kubelet and treat vSphere CSI migration as already complete. And directly redirect traffic to CSI driver for all vsphere volume related operations.

Design Details

[X] I/we understand the owners of the involved components may require updates to existing tests to make this code solid enough prior to committing the changes necessary to implement this enhancement.

Prerequisite testing updates

No additional prerequisite tests are needed.

Unit tests

Unit tests for vSphere CSI Migration is added in the csi-translation-lib repository

• https://github.com/kubernetes/csi-translation-lib/blob/master/plugins/vsphere_volume_test.go (85.1% coverage)

Integration tests

• No Integration tests required for this feature

e2e tests

• e2e storage test suite should pass before and after migration.
• Existing e2e tests developed for in-tree vSphere volume plugin executed - https://github.com/kubernetes/kubernetes/tree/master/test/e2e/storage/vsphere
• Additional tests added in the vSphere CSI Driver repository to ensure vSphere CSI Migration is production ready.
  • https://github.com/kubernetes-sigs/vsphere-csi-driver/blob/master/tests/e2e/vcp_to_csi_create_delete.go
  • https://github.com/kubernetes-sigs/vsphere-csi-driver/blob/master/tests/e2e/vcp_to_csi_attach_detach.go
  • https://github.com/kubernetes-sigs/vsphere-csi-driver/blob/master/tests/e2e/vcp_to_csi_full_sync.go
  • https://github.com/kubernetes-sigs/vsphere-csi-driver/blob/master/tests/e2e/vcp_to_csi_syncer.go

Production Readiness Review Questionnaire

Please refer to the CSI Migration Production Readiness Review Questionnaire.

Implementation History

Major milestones in the life cycle of a KEP should be tracked in Implementation History.

• 2022-01-11 KEP created

Major milestones for vSphere in-tree plugin CSI migration:

• 1.18

  • vSphere CSI migration to Alpha

• 1.19

  • vSphere CSI migration to Beta, off by default

• 1.25

  • vSphere CSI migration to Beta, On by default

• 1.26

  • vSphere CSI migration to Stable

• 1.27

  • vSphere CSI migration locked on

• 1.30

  • vSphere in-tree support eligible for removal (oldest supported n-3 nodes are 1.27 and have vSphere CSI migration enabled)