Backup Stand-alone PVC using KubeStash

This guide will show you how to use KubeStash to take backup of a stand-alone PersistentVolumeClaim (PVC).

Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.
Install KubeStash in your cluster following the steps here.
Here, we are going to use an NFS server to provision a PVC with ReadWriteOnce access mode. If you don’t have an NFS server running, deploy one by following the guide here.
You should be familiar with the following KubeStash concepts:

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/volumes/pvc/examples directory of kubestash/docs repository.

Prepare Volume

At first, let’s prepare our desired PVC. Here, we are going to create a PersistentVolume (PV) that will use an NFS server as storage. Then, we are going to create a PVC that will bind with the PV. Then, we are going to mount this PVC in two different pods. Each pod will generate a sample file into the PVC.

Create PersistentVolume:

We have deployed an NFS server in storage namespace and it is accessible through a Service named nfs-service. Now, we are going to create a PV that uses the NFS server as storage.

Below is the YAML of the PV that we are going to create,

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv
spec:
  capacity:
    storage: 1Gi
  accessModes:
    - ReadWriteOnce
  csi:
    driver: nfs.csi.k8s.io
    volumeHandle: nfs-server.storage.svc.cluster.local/share##
    volumeAttributes:
      server: nfs-server.storage.svc.cluster.local
      share: /

Notice the spec.csi section. Here, we have added csi driver information which represents that this storage is managed by an external CSI volume driver.

Let’s create the PV we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/pv.yaml
persistentvolume/nfs-pv created

Create PersistentVolumeClaim:

Now, create a PVC to bind with the PV we have just created. Below, is the YAML of the PVC that we are going to create,

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: nfs-pvc
  namespace: demo
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  volumeName: nfs-pv

Notice the spec.volumeName section. We have specified nfs-pv as the PV that we have created earlier, which will be claimed by above PVC.

Let’s create the PVC we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/pvc.yaml
persistentvolumeclaim/nfs-pvc created

Verify that the PVC has bounded with our desired PV,

$ kubectl get pvc -n demo nfs-pvc
NAME      STATUS   VOLUME   CAPACITY   ACCESS MODES   STORAGECLASS   AGE
nfs-pvc   Bound    nfs-pv   1Gi        RWX                           32s

Here, we can see that the PVC nfs-pvc has been bounded with PV nfs-pv.

Deploy Workload:

Now, we are going to deploy two sample pods demo-pod-1 and demo-pod-2 that will mount pod-1/data and pod-2/data subPath of the nfs-pvc respectively. Each of the pods will generate a sample file named hello.txt with some demo data.

Below, is the YAML of the first Pod that we are going to deploy,

kind: Pod
apiVersion: v1
metadata:
  name: demo-pod-1
  namespace: demo
spec:
  containers:
  - name: busybox
    image: busybox
    command: ["/bin/sh", "-c","echo 'hello from pod 1.' > /sample/data/hello.txt && sleep 3000"]
    volumeMounts:
    - name: my-volume
      mountPath: /sample/data
      subPath: pod-1/data
  volumes:
  - name: my-volume
    persistentVolumeClaim:
      claimName: nfs-pvc

Here, we have mounted pod-1/data directory of the nfs-pvc into /sample/data directory of this pod.

Let’s deploy the pod we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/pod-1.yaml
pod/demo-pod-1 created

Verify that the sample data has been generated into /sample/data/ directory,

$ kubectl exec -n demo demo-pod-1 -- cat /sample/data/hello.txt
hello from pod 1.

Below is the YAML of the second pod that we are going to deploy,

kind: Pod
apiVersion: v1
metadata:
  name: demo-pod-2
  namespace: demo
spec:
  containers:
  - name: busybox
    image: busybox
    command: ["/bin/sh", "-c","echo 'hello from pod 2.' > /sample/data/hello.txt && sleep 3000"]
    volumeMounts:
    - name: my-volume
      mountPath: /sample/data
      subPath: pod-2/data
  volumes:
  - name: my-volume
    persistentVolumeClaim:
      claimName: nfs-pvc

Now, we have mounted pod-2/data directory of the nfs-pvc into /sample/data directory of this pod.

Let’s create the pod we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/pod-2.yaml
pod/demo-pod-2 created

Verify that the sample data has been generated into /sample/data/ directory,

$ kubectl exec -n demo demo-pod-2 -- cat /sample/data/hello.txt
hello from pod 2.

Prepare Backend

Now, we are going to backup of the PVC nfs-pvc to a GCS bucket using KubeStash. For this, we have to create a Secret with necessary credentials and a BackupStorage object. If you want to use a different backend, please read the respective backend configuration doc from here.

For GCS backend, if the bucket does not exist, KubeStash needs Storage Object Admin role permissions to create the bucket. For more details, please check the following guide.

Create Secret:

Let’s create a Secret named gcs-secret with access credentials to our desired GCS bucket,

$ echo -n '<your-project-id>' > GOOGLE_PROJECT_ID
$ cat /path/to/downloaded/sa_key_file.json > GOOGLE_SERVICE_ACCOUNT_JSON_KEY
$ kubectl create secret generic -n demo gcs-secret \
    --from-file=./GOOGLE_PROJECT_ID \
    --from-file=./GOOGLE_SERVICE_ACCOUNT_JSON_KEY
secret/gcs-secret created

Create BackupStorage:

Now, create a BackupStorage custom resource specifying the desired bucket, and directory inside the bucket where the backed up data will be stored.

Below is the YAML of BackupStorage object that we are going to create,

apiVersion: storage.kubestash.com/v1alpha1
kind: BackupStorage
metadata:
  name: gcs-storage
  namespace: demo
spec:
  storage:
    provider: gcs
    gcs:
      bucket: kubestash-qa
      prefix: demo
      secretName: gcs-secret
  usagePolicy:
    allowedNamespaces:
      from: All
  default: true 
  deletionPolicy: WipeOut

Let’s create the BackupStorage object that we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/backupstorage.yaml
backupstorage.storage.kubestash.com/gcs-repo created

Now, we are ready to backup our target volume to this backend.

Create RetentionPolicy:

Now, we have to create a RetentionPolicy object to specify how the old Snapshots should be cleaned up.

Below is the YAML of the RetentionPolicy object that we are going to create,

apiVersion: storage.kubestash.com/v1alpha1
kind: RetentionPolicy
metadata:
  name: demo-retention
  namespace: demo
spec:
  default: true
  failedSnapshots:
    last: 2
  maxRetentionPeriod: 2mo
  successfulSnapshots:
    last: 5
  usagePolicy:
    allowedNamespaces:
      from: Same

Notice the spec.usagePolicy that allows referencing the RetentionPolicy from all namespaces.For more details on configuring it for specific namespaces, please refer to the following RetentionPolicy usage policy.

Let’s create the RetentionPolicy object that we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/retentionpolicy.yaml
retentionpolicy.storage.kubestash.com/demo-retention created

Backup

Now, we have to create a BackupConfiguration custom resource targeting the PVC that we have created earlier.

We also have to create another Secret with an encryption key RESTIC_PASSWORD for Restic. This secret will be used by Restic for both encrypting and decrypting the backup data during backup & restore.

Create Secret:

Let’s create a secret named encrypt-secret with the Restic password.

$ echo -n 'changeit' > RESTIC_PASSWORD
$ kubectl create secret generic -n demo encrypt-secret \
    --from-file=./RESTIC_PASSWORD 
secret/encrypt-secret created

Create BackupConfiguration:

Below is the YAML of the BackupConfiguration object that we are going to create,

apiVersion: core.kubestash.com/v1alpha1
kind: BackupConfiguration
metadata:
  name: nfs-pvc-backup
  namespace: demo
spec:
  target:
    apiGroup:
    kind: PersistentVolumeClaim
    name:  nfs-pvc
    namespace: demo
  backends:
    - name: gcs-backend
      storageRef:
        namespace: demo
        name: gcs-storage
      retentionPolicy:
        name: demo-retention
        namespace: demo
  sessions:
    - name: frequent-backup
      sessionHistoryLimit: 3
      scheduler:
        schedule: "*/5 * * * *"
        jobTemplate:
          backoffLimit: 1
      repositories:
        - name: gcs-repository
          backend: gcs-backend
          directory: /pvc-backup-demo
          encryptionSecret:
            name: encrypt-secret
            namespace: demo
          deletionPolicy: WipeOut
      addon:
        name: pvc-addon
        tasks:
          - name: logical-backup

Let’s create the BackupConfiguration object that we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/backupconfiguration.yaml
backupconfiguration.core.kubestash.com/nfs-pvc-backup created

Verify Backup Setup Successful

If everything goes well, the phase of the BackupConfiguration should be in Ready state. The Ready phase indicates that the backup setup is successful.

Let’s check the Phase of the BackupConfiguration

$ kubectl get backupconfiguration -n demo
NAME             PHASE   PAUSED   AGE
nfs-pvc-backup   Ready            19s

Verify Repository:

Verify that the Repository specified in the BackupConfiguration has been created using the following command,

$ kubectl get repositories -n demo
NAME             INTEGRITY   SNAPSHOT-COUNT   SIZE   PHASE   LAST-SUCCESSFUL-BACKUP   AGE
gcs-repository                                       Ready                            28s

KubeStash keeps the backup for Repository YAMLs. If we navigate to the GCS bucket, we will see the Repository YAML stored in the kubestash-qa/demo/pvc-backup-demo directory.

Verify CronJob:

Verify that KubeStash has created a CronJob with the schedule specified in spec.sessions[*].scheduler.schedule field of BackupConfiguration object.

Check that the CronJob has been created using the following command,

$ kubectl get cronjob -n demo
NAME                                     SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
trigger-nfs-pvc-backup-frequent-backup   */5 * * * *   False     0        5s              40s

Wait for BackupSession:

Now, wait for the next backup schedule. You can watch for BackupSession CR using the following command,

$ watch -n 1 kubectl get backupsession -n demo -l=kubestash.com/invoker-name=nfs-pvc-backup

Every 1.0s: kubectl get backupsession -n demo -l=kubestash.com/invoker-name=nfs-pvc-backup                                                                                           workstation: Wed Jan  3 17:26:00 2024

NAME                                        INVOKER-TYPE          INVOKER-NAME     PHASE       DURATION   AGE
nfs-pvc-backup-frequent-backup-1704281100   BackupConfiguration   nfs-pvc-backup   Succeeded              60s

Here, the phase Succeeded means that the backup process has been completed successfully.

Verify Backup:

When backup session is complete, KubeStash will update the respective Repository to reflect the latest state of backed up data.

$ kubectl get repositories -n demo
NAME             INTEGRITY   SNAPSHOT-COUNT   SIZE        PHASE   LAST-SUCCESSFUL-BACKUP   AGE
gcs-repository   true        1                2.262 KiB   Ready   103s                     8m

At this moment we have one Snapshot. Run the following command to check the respective Snapshot.

Verify created Snapshot object by the following command,

$ kubectl get snapshots -n demo -l=kubestash.com/repo-name=gcs-repository
NAME                                                       REPOSITORY       SESSION           SNAPSHOT-TIME          DELETION-POLICY   PHASE       VERIFICATION-STATUS   AGE
gcs-repository-nfs-pvc-backup-frequent-backup-1704281100   gcs-repository   frequent-backup   2024-01-03T11:25:13Z   Delete            Succeeded                         2m14s

Note: KubeStash creates a Snapshot with the following labels:
kubestash.com/app-ref-kind: <target-kind>
kubestash.com/app-ref-name: <target-name>
kubestash.com/app-ref-namespace: <target-namespace>
kubestash.com/repo-name: <repository-name>
These labels can be used to watch only the Snapshots related to our desired Workload or Repository.

Now, lets retrieve the YAML for the Snapshot, and inspect the spec.status section to see the backup up components of the PVC.

$ kubectl get snapshots -n demo gcs-repository-nfs-pvc-backup-frequent-backup-1704281100 -oyaml

apiVersion: storage.kubestash.com/v1alpha1
kind: Snapshot
metadata:
  labels:
    kubestash.com/app-ref-kind: PersistentVolumeClaim
    kubestash.com/app-ref-name: nfs-pvc
    kubestash.com/app-ref-namespace: demo
    kubestash.com/repo-name: gcs-repository
  name: gcs-repository-nfs-pvc-backup-frequent-backup-1704281100
  namespace: demo
spec:
  ...
status:
  components:
    dump:
      driver: Restic
      duration: 7.534461497s
      integrity: true
      path: repository/v1/frequent-backup/dump
      phase: Succeeded
      resticStats:
      - hostPath: /kubestash-data
        id: f28441a36b2167d64597d66d1046573181cad81aa8ff5b0998b64b31ce16f077
        size: 11 B
        uploaded: 1.049 KiB
      size: 806 B
  ...

For stand-alone PVC, KubeStash takes backup from a stand-alone PVC. So, only one component has been taken backup. We use dump as the component name for a stand-alone PVC.

Now, if we navigate to the GCS bucket, we will see the backed up data stored in the kubestash-qa/demo/pvc-backup-demo/repository/v1/frequent-backup/dump directory. KubeStash also keeps the backup for Snapshot YAMLs, which can be found in the kubestash-qa/demo/pvc-backup-demo/repository/snapshots directory.

Fig: Backed up data of a stand-alone PVC in GCS backend

Note: KubeStash stores all dumped data encrypted in the backup directory, meaning it remains unreadable until decrypted.

Restore

This section will show you how to restore the backed up data inside a stand-alone PVC using KubeStash. Here, we are going to restore the data we have backed up in the previous section.

Simulate Disaster:

At first, let’s simulate a disaster scenario. Let’s delete all the files from the PVC.

Delete the data of pod demo-pod-1:

# delete data
$ kubectl exec -n demo demo-pod-1 -- sh -c "rm /sample/data/*"

# verify that data has been removed successfully
$ kubectl exec -n demo demo-pod-1 -- ls /sample/data/
# empty output which means all the files have been deleted

Delete the data of pod demo-pod-2:

# delete data
$ kubectl exec -n demo demo-pod-2 -- sh -c "rm /sample/data/*"

# verify that data has been removed successfully
$ kubectl exec -n demo demo-pod-2 -- ls /sample/data/
# empty output which means all the files have been deleted

Create RestoreSession:

Now, we are going to create a RestoreSession object to restore the backed up data into the desired PVC.

Below is the YAML of the RestoreSession object that we are going to create,

apiVersion: core.kubestash.com/v1alpha1
kind: RestoreSession
metadata:
  name: nfs-pvc-restore
  namespace: demo
spec:
  target:
    apiGroup:
    kind: PersistentVolumeClaim
    name: nfs-pvc
    namespace: demo
  dataSource:
    repository: gcs-repository
    snapshot: latest
    encryptionSecret:
      name: encrypt-secret
      namespace: demo
  addon:
    name: pvc-addon
    tasks:
      - name: logical-backup-restore

spec.target refers to the targeted PVC where the data will be restored.
spec.dataSource.repository specifies the name of the Repository from which the data will be restored.
spec.dataSource.snapshot specifies that we want to restore the latest snapshot of the gcs-repository.
spec.dataSource.encryptionSecret specifies the encryption secret for Restic Repository used during backup. It will be used to decrypting the backup data.

Let’s create the RestoreSession object that we have shown above,

$ kubectl apply -f https://github.com/kubestash/docs/raw/v2024.8.14/docs/guides/volumes/pvc/examples/restoresession.yaml
restoresession.core.kubestash.com/nfs-pvc-restore created

Wait for RestoreSession to Succeed:

Once, you have created the RestoreSession object, KubeStash will create restore Job. Wait for the restore process to complete.

You can watch the RestoreSession phase using the following command,

$ watch -n 1 kubectl get restoresession -n demo

Every 1.0s: kubectl get restoresession -n demo nfs-pvc...  workstation: Wed Jan  3 17:30:20 2024

NAME              REPOSITORY       FAILURE-POLICY   PHASE       DURATION   AGE
nfs-pvc-restore   gcs-repository                    Succeeded   10s        51s

From the output of the above command, the Succeeded phase indicates that the restore process has been completed successfully.

Verify Restored Data:

Let’s verify if the deleted files have been restored successfully into the PVC. We are going to exec into individual pod and check whether the sample data exist or not.

Verify that the data of demo-pod-1 has been restored:

$ kubectl exec -n demo demo-pod-1 -- cat /sample/data/hello.txt
hello from pod 1.

Verify that the data of demo-pod-2 has been restored:

$ kubectl exec -n demo demo-pod-2 -- cat /sample/data/hello.txt
hello from pod 2.

So, we can see from the above output that the files we had deleted in Simulate Disaster section have been restored successfully.

Cleanup

To cleanup the Kubernetes resources created by this tutorial, run:


kubectl delete backupconfiguration -n demo nfs-pvc-backup
kubectl delete restoresession -n demo nfs-pvc-restore

kubectl delete backupstorage -n demo gcs-storage
kubectl delete retentionPolicy -n demo demo-retention

kubectl delete secret -n demo gcs-secret
kubectl delete secret -n demo encrypt-secret

kubectl delete pod -n demo demo-pod-1
kubectl delete pod -n demo demo-pod-2

kubectl delete pvc -n demo nfs-pvc
kubectl delete pv -n demo nfs-pv

If you would like to uninstall KubeStash operator, please follow the steps here.

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