You are looking at the documentation of a prior release. To read the documentation of the latest release, please
visit here.
Snapshotting the volumes of a Deployment
This guide will show you how to use Stash to snapshot the volumes of a Deployment and restore them from the snapshots using Kubernetes VolumeSnapshot API. In this guide, we are going to backup the volumes in Google Cloud Platform with the help of GCE Persistent Disk CSI Driver.
Before You Begin
- You need to be familiar with the GCE Persistent Disk CSI Driver.
- Install
Stash
in your cluster following the steps here. - If you don’t know how VolumeSnapshot works in Stash, please visit here.
Prepare for VolumeSnapshot
Here, we are going to create StorageClass
that uses GCE Persistent Disk CSI Driver.
Below is the YAML of the StorageClass
we are going to use,
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
name: csi-standard
parameters:
type: pd-standard
provisioner: pd.csi.storage.gke.io
reclaimPolicy: Delete
volumeBindingMode: Immediate
Let’s create the StorageClass
we have shown above,
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/storageclass.yaml
storageclass.storage.k8s.io/csi-standard created
We also need a VolumeSnapshotClass
. Below is the YAML of the VolumeSnapshotClass
we are going to use,
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshotClass
metadata:
name: csi-snapshot-class
driver: pd.csi.storage.gke.io
deletionPolicy: Delete
Here,
driver
field to point to the respective CSI driver that is responsible for taking snapshot. As we are using GCE Persistent Disk CSI Driver, we are going to usepd.csi.storage.gke.io
in this field.
Let’s create the volumeSnapshotClass
we have shown above,
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/volumesnapshotclass.yaml
volumesnapshotclass.snapshot.storage.k8s.io/csi-snapshot-class created
To keep everything isolated, we are going to use a separate namespace called demo
throughout this tutorial.
$ kubectl create ns demo
namespace/demo created
Note: YAML files used in this tutorial are stored in /docs/guides/volumesnapshot/deployment/examples directory of stashed/docs repository.
Take Volume Snapshot
Here, we are going to deploy a Deployment with two PVCs and generate some sample data in it. Then, we are going to take snapshot of these PVCs using Stash.
Create PersistentVolumeClaim :
At first, let’s create two sample PVCs. We are going to mount these PVCs in our targeted Deployment.
Below is the YAML of the sample PVCs,
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: source-data
namespace: demo
spec:
accessModes:
- ReadWriteOnce
storageClassName: csi-standard
resources:
requests:
storage: 1Gi
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: source-config
namespace: demo
spec:
accessModes:
- ReadWriteOnce
storageClassName: csi-standard
resources:
requests:
storage: 1Gi
:et’s create the PVCs we have shown above.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/pvcs.yaml
persistentvolumeclaim/source-data created
persistentvolumeclaim/source-config created
Deploy Deployment :
Now, we are going to deploy a Deployment that uses the above PVCs. This Deployment will automatically create data.txt
and config.cfg
file in /source/data
and /source/config
directory.
Below is the YAML of the Deployment that we are going to create,
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: stash-demo
name: stash-demo
namespace: demo
spec:
replicas: 1
selector:
matchLabels:
app: stash-demo
template:
metadata:
labels:
app: stash-demo
name: busybox
spec:
containers:
- args: ["echo sample_data > /source/data/data.txt; echo sample_config > /source/config/config.cfg && sleep 3000"]
command: ["/bin/sh", "-c"]
image: busybox
imagePullPolicy: IfNotPresent
name: busybox
volumeMounts:
- mountPath: /source/data
name: source-data
- mountPath: /source/config
name: source-config
restartPolicy: Always
volumes:
- name: source-data
persistentVolumeClaim:
claimName: source-data
- name: source-config
persistentVolumeClaim:
claimName: source-config
Let’s create the deployment we have shown above.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/deployment.yaml
deployment.apps/stash-demo created
Now, wait for the pod of the Deployment to go into the Running
state.
$ kubectl get pod -n demo
NAME READY STATUS RESTARTS AGE
stash-demo-7fd48dd5b4-xqv5n 1/1 Running 0 2m10s
Verify that the sample data has been created in /source/data
and /source/config
directory using the following command,
$ kubectl exec -n demo stash-demo-7fd48dd5b4-xqv5n -- cat /source/data/data.txt
sample_data
$ kubectl exec -n demo stash-demo-7fd48dd5b4-xqv5n -- cat /source/config/config.cfg
config_data
Create BackupConfiguration :
Now, create a BackupConfiguration
object to take snapshot of the PVCs of stash-demo
Deployment.
Below is the YAML of the BackupConfiguration
that we are going to create,
apiVersion: stash.appscode.com/v1beta1
kind: BackupConfiguration
metadata:
name: deployment-volume-snapshot
namespace: demo
spec:
schedule: "*/5 * * * *"
driver: VolumeSnapshotter
target:
ref:
apiVersion: apps/v1
kind: Deployment
name: stash-demo
snapshotClassName: csi-snapshot-class
retentionPolicy:
name: 'keep-last-5'
keepLast: 5
prune: true
Here,
spec.schedule
is a cron expression that indicatesBackupSession
will be created at 5 minutes interval.spec.driver
indicates the name of the agent to use to back up the target. Currently, Stash supportsRestic
andVolumeSnapshotter
drivers. TheVolumeSnapshotter
is used to backup/restore PVC usingVolumeSnapshot
API.spec.target.ref
refers to the backup target.apiVersion
,kind
andname
refers to theapiVersion
,kind
andname
of the targeted workload respectively. Stash will use this information to create a Volume Snapshotter Job for creating VolumeSnapshot.spec.target.snapshotClassName
indicates the VolumeSnapshotClass to be used for volume snapshotting.
Let’s create the BackupConfiguration
object we have shown above.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/backupconfiguration.yaml
backupconfiguration.stash.appscode.com/deployment-volume-snapshot created
Verify Backup Setup Successful:
If everything goes well, the phase of the BackupConfiguration
should be Ready
. The Ready
phase indicates that the backup setup is successful. Let’s verify the Phase of the BackupConfiguration
,
$ kubectl get backupconfiguration -n demo
NAME TASK SCHEDULE PAUSED PHASE AGE
deployment-volume-snapshot */5 * * * * Ready 11s
Verify CronJob :
Stash will create a CronJob with the schedule specified in spec.schedule
field of BackupConfiguration
CRD. Verify that the CronJob has been created using the following command,
$ kubectl get cronjob -n demo
NAME SCHEDULE SUSPEND ACTIVE LAST SCHEDULE AGE
deployment-volume-snapshot */1 * * * * False 0 39s 2m41s
Wait for BackupSession :
The deployment-volume-snapshot
CronJob will trigger a backup on each schedule by creating a BackupSession
crd.
Wait for the next schedule for backup. Run the following command to watch BackupSession
crd,
$ watch -n 1 kubectl get backupsession -n demo
Every 1.0s: kubectl get backupsession -n demo
NAME INVOKER-TYPE INVOKER-NAME PHASE AGE
deployment-volume-snapshot-fnbwz BackupConfiguration deployment-volume-snapshot Succeeded 50s
We can see above that the BackupSession has been succeeded. Now, we are going to verify that the VolumeSnapshot
has been created and the snapshots has been stored in the respective backend.
Verify Volume Snapshot :
Once a BackupSession
crd is created, it creates volume snapshotter Job
. Then the Job
creates VolumeSnapshot
crd for the targeted PVCs.
Check that the VolumeSnapshot
has been created Successfully.
$ kubectl get volumesnapshot -n demo
NAME AGE
source-config-fnbwz 1m46s
source-data-fnbwz 1m46s
Let’s find the name of the snapshot that has been saved in the Google Cloud by the following command,
kubectl get volumesnapshot source-data-fnbwz -n demo -o yaml
apiVersion: snapshot.storage.k8s.io/v1
kind: VolumeSnapshot
metadata:
creationTimestamp: "2019-07-15T06:14:09Z"
finalizers:
- snapshot.storage.kubernetes.io/volumesnapshot-protection
generation: 4
name: source-data-fnbwz
namespace: demo
resourceVersion: "9220"
selfLink: /apis/snapshot.storage.k8s.io/v1/namespaces/demo/volumesnapshots/source-data-fnbwz
uid: c1bc3390-a6c7-11e9-9f3a-42010a800050
spec:
source:
persistentVolumeClaimName: source-data
volumeSnapshotClassName: csi-snapshot-class
status:
boundVolumeSnapshotContentName: snapcontent-c1bc3390-a6c7-11e9-9f3a-42010a800050
creationTime: "2019-07-15T06:14:10Z"
readyToUse: true
restoreSize: 1Gi
Here, status.snapshotContentName
field specifies the name of the VolumeSnapshotContent
crd. It also represents the actual snapshot name that has been saved in Google Cloud. If we navigate to the Snapshots
tab in the GCP console, we are going to see the snapshot snapcontent-c1bc3390-a6c7-11e9-9f3a-42010a800050
has been stored successfully.
![Stash Backup Flow](/docs/v2023.01.05/guides/volumesnapshot/deployment/images/gcp.png)
Restore PVC from VolumeSnapshot
This section will show you how to restore the PVCs from the snapshots we have taken in the previous section.
Stop Taking Backup of the Old Deployment:
At first, let’s stop taking any further backup of the old Deployment so that no backup is taken during the restore process. We are going to pause the BackupConfiguration
that we created to backup the stash-demo
Deployment. Then, Stash will stop taking any further backup for this Deployment. You can learn more how to pause a scheduled backup here
Let’s pause the deployment-volume-snapshot
BackupConfiguration,
$ kubectl patch backupconfiguration -n demo deployment-volume-snapshot --type="merge" --patch='{"spec": {"paused": true}}'
backupconfiguration.stash.appscode.com/deployment-volume-snapshot patched
Now, wait for a moment. Stash will pause the BackupConfiguration. Verify that the BackupConfiguration has been paused,
$ kubectl get backupconfiguration -n demo
NAME TASK SCHEDULE PAUSED AGE
deployment-volume-snapshot */1 * * * * true 18m
Notice the PAUSED
column. Value true
for this field means that the BackupConfiguration has been paused.
Create RestoreSession :
At first, we have to create a RestoreSession
crd to restore the PVCs from the respective snapshot.
Below is the YAML of the RestoreSesion
crd that we are going to create,
apiVersion: stash.appscode.com/v1beta1
kind: RestoreSession
metadata:
name: restore-pvc
namespace: demo
spec:
driver: VolumeSnapshotter
target:
volumeClaimTemplates:
- metadata:
name: restore-data
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: "csi-standard"
resources:
requests:
storage: 1Gi
dataSource:
kind: VolumeSnapshot
name: source-data-fnbwz
apiGroup: snapshot.storage.k8s.io
- metadata:
name: restore-config
spec:
accessModes: [ "ReadWriteOnce" ]
storageClassName: "csi-standard"
resources:
requests:
storage: 1Gi
dataSource:
kind: VolumeSnapshot
name: source-config-fnbwz
apiGroup: snapshot.storage.k8s.io
Here,
spec.target.volumeClaimTemplates
:metadata.name
is a template for the name of the restored PVC that will be created by Stash. You have to provide this named template to match with the desired PVC of your Deployment.spec.dataSource
:spec.dataSource
specifies the source of the data from where the newly created PVC will be initialized. It requires the following fields to be set:apiGroup
is the group for resource being referenced. Now, Kubernetes supports onlysnapshot.storage.k8s.io
.kind
is resource of the kind being referenced. Now, Kubernetes supports onlyVolumeSnapshot
.name
is theVolumeSnapshot
resource name. InRestoreSession
crd, You must set the VolumeSnapshot name directly.
Let’s create the RestoreSession
crd we have shown above.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/restoresession.yaml
restoresession.stash.appscode.com/restore-pvc created
Once, you have created the RestoreSession
crd, Stash will create a job to restore. We can watch the RestoreSession
phase to check if the restore process has been succeeded or not.
Run the following command to watch RestoreSession phase,
$ watch -n 1 kubectl get -n demo restoresession -n
Every 1.0s: kubectl get restore -n demo
NAME REPOSITORY-NAME PHASE AGE
restore-pvc Running 10s
restore-pvc Succeeded 1m
So, we can see from the output of the above command that the restore process succeeded.
Verify Restored PVC :
Once the restore process is complete, we are going to see that new PVCs with the name restore-data
and restore-config
have been created.
Verify that the PVCs have been created by the following command,
$ kubectl get pvc -n demo
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
restore-config Bound pvc-26758eda-a6ca-11e9-9f3a-42010a800050 1Gi RWO standard 30s
restore-data Bound pvc-267335ff-a6ca-11e9-9f3a-42010a800050 1Gi RWO standard 30s
Notice the STATUS
field. It indicates that the respective PV has been provisioned and initialized from the respective VolumeSnapshot by CSI driver and the PVC has been bound with the PV.
The volumeBindingMode field controls when volume binding and dynamic provisioning should occur. Kubernetes allows
Immediate
andWaitForFirstConsumer
modes for binding volumes. TheImmediate
mode indicates that volume binding and dynamic provisioning occurs once the PVC is created andWaitForFirstConsumer
mode indicates that volume binding and provisioning does not occur until a pod is created that uses this PVC. By defaultvolumeBindingMode
isImmediate
.
If you use
volumeBindingMode: WaitForFirstConsumer
, respective PVC will be initialized from respective VolumeSnapshot after you create a workload with that PVC. In this case, Stash will mark the restore session as completed with phaseUnknown
.
Verify Restored Data :
We are going to create a new Deployment with the restored PVCs to verify whether the backed up data has been restored.
Below is the YAML of the Deployment that we are going to create,
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: restore-demo
name: restore-demo
namespace: demo
spec:
replicas: 1
selector:
matchLabels:
app: restore-demo
template:
metadata:
labels:
app: restore-demo
name: busybox
spec:
containers:
- args:
- sleep
- "3600"
image: busybox
imagePullPolicy: IfNotPresent
name: busybox
volumeMounts:
- mountPath: /restore/data
name: restore-data
- mountPath: /restore/config
name: restore-config
restartPolicy: Always
volumes:
- name: restore-data
persistentVolumeClaim:
claimName: restore-data
- name: restore-config
persistentVolumeClaim:
claimName: restore-config
Let’s create the deployment we have shown above.
$ kubectl apply -f https://github.com/stashed/docs/raw/v2023.01.05/docs/guides/volumesnapshot/deployment/examples/restored-deployment.yaml
deployment.apps/restore-demo created
Now, wait for the pod of the Deployment to go into the Running
state.
$ kubectl get pod -n demo
NAME READY STATUS RESTARTS AGE
restore-demo-544db78b8b-tnzb2 1/1 Running 0 34s
Verify that the backed up data has been restored in /restore/data
and /restore/config
directory using the following command,
$ kubectl exec -n demo restore-demo-544db78b8b-tnzb2 ls /restore/config/config.cfg
config_data
$ kubectl exec -n demo restore-demo-544db78b8b-tnzb2 ls /restore/data/data.txt
sample_data
Cleaning Up
To clean up the Kubernetes resources created by this tutorial, run:
kubectl delete -n demo deployment stash-demo
kubectl delete -n demo deployment restore-demo
kubectl delete -n demo backupconfiguration deployment-volume-snapshot
kubectl delete -n demo restoresession restore-pvc
kubectl delete -n demo storageclass csi-standard
kubectl delete -n demo volumesnapshotclass csi-snapshot-class