KEP-2924: In-tree Storage Plugin to CSI Migration - Ceph Cephfs

Implementation History
ALPHA Withdrawn
Created 2022-01-27
Updated 2023-05-28
Latest v1.28
Milestones
Alpha v1.26
Related Enhancements
Ownership
Owning SIG
SIG Storage
Participating SIGs
SIG Cluster Lifecycle
Primary Authors
@humblec

In-tree Storage Plugin to CSI Migration - Ceph Cephfs Design Doc

Table of Contents

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 described in its parent KEP. For all other contents, please refer to the parent KEP.

New Feature Gates

  • CSIMigrationCephfs
    • 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/cephfs will be redirected to use the corresponding CSI driver. From a user perspective, nothing will be noticed.
  • InTreePluginCephFSUnregister
    • 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/cephfs as one of the in-tree storage plugin provisioners. This flag standalone can work out of CSI Migration features.
    • However, when all InTreePluginCephfsUnregister, CSIMigrationCephfs and CSIMigration feature flags are enabled at the same time. The kube-controller-manager will skip the feature flag checking on kubelet and treat Ceph Cephfs CSI migration as already complete. And directly redirect traffic to CSI driver for all cephfs related operations.

Design Details

Test Plan

[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 tests are needed, rather the issue is orchestrating CSI driver deployment for prow jobs. This means that it is not possible to run any test for cephfs in k/k repository.

Unit tests

+- k8s.io/csi-translation-lib/blob/master/plugins/cephfs_test.go: 2022-06-27 - 69.7

Integration tests

N/A

e2e tests

Support for tests after CephFS migration will be performed by the subjected CephFS csi driver which is available here . Addition to above, in-tree CephFS driver tests available here also cover the e2e part of this feature..

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.

  • 2022-01-27 KEP created

Major milestones for Ceph Cephfs in-tree plugin CSI migration:

  • 1.26
    • Ceph Cephfs CSI migration to Alpha