What is persistent-volume-migrator?

The persistent-volume-migrator tool aims to help migrate Flex RBD Volumes to Ceph-CSI RBD Volumes.

Migration between Ceph-CSI Volumes is also supported.

Note Migration of CephFS Volumes is not supported for now.

Getting Started

NOTE: The procedure will come with downtime while the applications are scaled down for the volume migration.

Prerequisite

This guide assumes you have created a Rook-Ceph cluster with Flex and Ceph-CSI.

We assume that you have healthy cluster i.e. ceph status shows health: OK
Minimum ceph version should be Ceph-CSI supported. Check Ceph-CSI supported versions.
Stop the application pods that are consuming the flex volume(s) that need to be converted.
Ceph-CSI storageClass should be created in which you want to migrate.

Steps to Migrate

Stop the application pods that are consuming the flex volume(s) that need to be converted.
Create migrator pod kubectl create -f manifests/migrator.yaml
Download the binary from release
1. wget https://github.com/ceph/persistent-volume-migrator/releases/download/v0.1.0-alpha/pv-migrator
Run the command to migrate the PVC(s)

NOTE: source and destination StorageClass should use the same pool.

Usage

Migrate a Single PVC

pv-migrator --pvc=<pvc-name> --pvc-namespace=<pvc-namespace>
   --destination-sc=<csi-storageclass-name-to-migrate>
   [--rook-namespace=rook-operator-namespace]
   [--ceph-cluster-namespace=ceph-cluster-namespace]

--pvc: required: name of the pvc to migrate
--pvc-ns: required: namespace of the PVC which is going to migrate
--destination-sc: required: name of the storageclass in which you want mirgrate.
--rook-ns: optional namespace where the rook operator is running. default: rook-ceph.
--ceph-cluster-ns: optional namespace where the ceph cluster is running. default: rook-ceph.

Example:

pv-migrator --pvc=rbd-pvc --pvc-ns=default --destination-sc=csi-rook-ceph-block

I1125 07:56:22.247311      63 log.go:34] Create Kubernetes Client
I1125 07:56:22.259115      63 log.go:34] List all the PVC from the source storageclass
I1125 07:56:22.261205      63 log.go:34] 1 PVCs found with source StorageClass
I1125 07:56:22.261221      63 log.go:34] Start Migration of PVCs to CSI
I1125 07:56:22.261226      63 log.go:34] migrating PVC "rbd-pvc" from namespace "default"
I1125 07:56:22.261229      63 log.go:34] Fetch PV information from PVC rbd-pvc
I1125 07:56:22.266734      63 log.go:34] PV found "pvc-30a01887-8821-4baf-835c-16a7e55ba7f0"
---
I1125 07:56:26.483172      63 log.go:34] successfully renamed volume csi-vol-2f8de58f-4dc5-11ec-a130-0242ac110005 -> pvc-30a01887-8821-4baf-835c-16a7e55ba7f0
I1125 07:56:26.483194      63 log.go:34] Delete old PV object: pvc-30a01887-8821-4baf-835c-16a7e55ba7f0
I1125 07:56:26.504578      63 log.go:34] waiting for PV pvc-30a01887-8821-4baf-835c-16a7e55ba7f0 in state &PersistentVolumeStatus{Phase:Bound,Message:,Reason:,} to be deleted (0 seconds elapsed)
I1125 07:56:26.702921      63 log.go:34] deleted persistent volume pvc-30a01887-8821-4baf-835c-16a7e55ba7f0
I1125 07:56:26.702944      63 log.go:34] successfully migrated pvc rbd-pvc
I1125 07:56:26.703335      63 log.go:34] Successfully migrated all the PVCs to CSI

Migrate All PVCs in a StorageClass

pv-migrator --source-storageclass=<flex-vol-storageclass>
   --destination-sc=<csi-storageclass-name-to-migrate>
   [--rook-namespace=rook-operator-namespace]
   [--ceph-cluster-namespace=ceph-cluster-namespace]

--source-sc: required: name of the storageclass in which you have your PVCs.
--destination-sc: required: name of the storageclass to which you want to migrate.
--rook-ns: optional namespace where the rook operator is running. default: rook-ceph.
--ceph-cluster-ns: optional namespace where the ceph cluster is running. default: rook-ceph.