Ceph
PLEASE NOTE: This document applies to v1.8 version and not to the latest stable release v1.9
Prerequisites
-
Rook officially supports v1/v1beta1 snapshots for kubernetes v1.17+.
-
Install the snapshot controller and snapshot v1/v1beta1 CRD as required. More info can be found here.
Note: If only Alpha snapshots are available, enable snapshotter in rook-ceph-operator-config
or helm chart values.yaml
, change the external-snapshotter image to k8s.gcr.io/sig-storage/csi-snapshotter:v1.2.2
and refer to the alpha snapshots documentation
- We also need a
VolumeSnapshotClass
for volume snapshot to work. The purpose of aVolumeSnapshotClass
is defined in the kubernetes documentation. In short, as the documentation describes it:
Just like StorageClass provides a way for administrators to describe the “classes” of storage they offer when provisioning a volume, VolumeSnapshotClass provides a way to describe the “classes” of storage when provisioning a volume snapshot.
Upgrade Snapshot API
If your Kubernetes version is updated to a newer version of the snapshot API, follow the upgrade guide here to upgrade from v1alpha1 to v1beta1, or v1beta1 to v1.
RBD Snapshots
VolumeSnapshotClass
In VolumeSnapshotClass,
the csi.storage.k8s.io/snapshotter-secret-name
parameter should reference the
name of the secret created for the rbdplugin and pool
to reflect the Ceph pool name.
Update the value of the clusterID
field to match the namespace that Rook is
running in. When Ceph CSI is deployed by Rook, the operator will automatically
maintain a configmap whose contents will match this key. By default this is
“rook-ceph”.
kubectl create -f deploy/examples/csi/rbd/snapshotclass.yaml
Volumesnapshot
In snapshot,
volumeSnapshotClassName
should be the name of the VolumeSnapshotClass
previously created. The persistentVolumeClaimName
should be the name of the
PVC which is already created by the RBD CSI driver.
kubectl create -f deploy/examples/csi/rbd/snapshot.yaml
Verify RBD Snapshot Creation
kubectl get volumesnapshotclass
NAME DRIVER DELETIONPOLICY AGE csi-rbdplugin-snapclass rook-ceph.rbd.csi.ceph.com Delete 3h55m
kubectl get volumesnapshot
NAME READYTOUSE SOURCEPVC SOURCESNAPSHOTCONTENT RESTORESIZE SNAPSHOTCLASS SNAPSHOTCONTENT CREATIONTIME AGE rbd-pvc-snapshot true rbd-pvc 1Gi csi-rbdplugin-snapclass snapcontent-79090db0-7c66-4b18-bf4a-634772c7cac7 3h50m 3h51m
The snapshot will be ready to restore to a new PVC when the READYTOUSE
field of the
volumesnapshot
is set to true.
Restore the snapshot to a new PVC
In
pvc-restore,
dataSource
should be the name of the VolumeSnapshot
previously
created. The dataSource
kind should be the VolumeSnapshot
.
Create a new PVC from the snapshot
kubectl create -f deploy/examples/csi/rbd/pvc-restore.yaml
Verify RBD Clone PVC Creation
kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE rbd-pvc Bound pvc-84294e34-577a-11e9-b34f-525400581048 1Gi RWO rook-ceph-block 34m rbd-pvc-restore Bound pvc-575537bf-577f-11e9-b34f-525400581048 1Gi RWO rook-ceph-block 8s
RBD snapshot resource Cleanup
To clean your cluster of the resources created by this example, run the following:
kubectl delete -f deploy/examples/csi/rbd/pvc-restore.yaml
kubectl delete -f deploy/examples/csi/rbd/snapshot.yaml
kubectl delete -f deploy/examples/csi/rbd/snapshotclass.yaml
CephFS Snapshots
VolumeSnapshotClass
In VolumeSnapshotClass,
the csi.storage.k8s.io/snapshotter-secret-name
parameter should reference the
name of the secret created for the cephfsplugin.
In the volumesnapshotclass, update the value of the clusterID
field to match the namespace that Rook is
running in. When Ceph CSI is deployed by Rook, the operator will automatically
maintain a configmap whose contents will match this key. By default this is
“rook-ceph”.
kubectl create -f deploy/examples/csi/cephfs/snapshotclass.yaml
Volumesnapshot
In snapshot,
volumeSnapshotClassName
should be the name of the VolumeSnapshotClass
previously created. The persistentVolumeClaimName
should be the name of the
PVC which is already created by the CephFS CSI driver.
kubectl create -f deploy/examples/csi/cephfs/snapshot.yaml
Verify CephFS Snapshot Creation
kubectl get volumesnapshotclass
NAME DRIVER DELETIONPOLICY AGE csi-cephfslugin-snapclass rook-ceph.cephfs.csi.ceph.com Delete 3h55m
kubectl get volumesnapshot
NAME READYTOUSE SOURCEPVC SOURCESNAPSHOTCONTENT RESTORESIZE SNAPSHOTCLASS SNAPSHOTCONTENT CREATIONTIME AGE cephfs-pvc-snapshot true cephfs-pvc 1Gi csi-cephfsplugin-snapclass snapcontent-34476204-a14a-4d59-bfbc-2bbba695652c 3h50m 3h51m
The snapshot will be ready to restore to a new PVC when READYTOUSE
field of the
volumesnapshot
is set to true.
Restore the snapshot to a new PVC
In
pvc-restore,
dataSource
should be the name of the VolumeSnapshot
previously
created. The dataSource
kind should be the VolumeSnapshot
.
Create a new PVC from the snapshot
kubectl create -f deploy/examples/csi/cephfs/pvc-restore.yaml
Verify CephFS Restore PVC Creation
kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE cephfs-pvc Bound pvc-74734901-577a-11e9-b34f-525400581048 1Gi RWX rook-cephfs 55m cephfs-pvc-restore Bound pvc-95308c75-6c93-4928-a551-6b5137192209 1Gi RWX rook-cephfs 34s
CephFS snapshot resource Cleanup
To clean your cluster of the resources created by this example, run the following:
kubectl delete -f deploy/examples/csi/cephfs/pvc-restore.yaml
kubectl delete -f deploy/examples/csi/cephfs/snapshot.yaml
kubectl delete -f deploy/examples/csi/cephfs/snapshotclass.yaml
Limitations
- There is a limit of 400 snapshots per cephFS filesystem.
- The PVC cannot be deleted if it has snapshots. make sure all the snapshots on the PVC are deleted before you delete the PVC.