KEP-1885: In-tree Storage Plugin to CSI Migration - Azurefile

Implementation History
STABLE Implemented
Created 2022-01-11
Updated 2022-01-11
Latest v1.26
Milestones
Alpha v1.15
Beta v1.21
Stable v1.26
Related Enhancements
Ownership
Owning SIG
SIG Storage
Participating SIGs
SIG Cluster Lifecycle
Primary Authors
@andyzhangx

In-tree Storage Plugin to CSI Migration - Azure File 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 as described in its parent KEP. For all other contents, please refer to the parent KEP.

New Feature Gates

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

Production Readiness Review Questionnaire

Please refer to the CSI Migration Production Readiness Review Questionnaire .

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 has been complicated by the cloud provider extraction work, which no longer permits cloud provider specific orchestration in the k/k repository. This means that it is not possible to run any test for AzureFile in k/k. All such tests have been moved to the Azure File CSI Driver repo .

Unit tests

https://github.com/kubernetes/csi-translation-lib/blob/master/plugins/azure_file_test.go

Integration tests

N/A

e2e tests

Support for tests after AzureFile migration have been added to azurefile-csi-driver .

The e2e tests are now covered in azurefile-csi-driver-e2e-migration .

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 Azure File in-tree plugin CSI migration:

  • 1.15

    • AzureFile CSI migration to Alpha

  • 1.21

    • AzureFile CSI migration to Beta, off by default

  • 1.24

    • AzureFile CSI migration to Beta, on by default

  • 1.26

    • AzureFile CSI migration to GA, on by default

  • 1.27

    • AzureFile CSI migration locked on

  • 1.30

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