Backup and Restore ZooKeeper using KubeStash

KubeStash allows you to backup and restore ZooKeeper. KubeStash makes managing your ZooKeeper backups and restorations more straightforward and efficient.

This guide will give you an overview how you can take backup and restore your ZooKeeper using Kubestash.

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 Minikube or Kind.
Install KubeDB in your cluster following the steps here.
Install KubeStash in your cluster following the steps here.
Install KubeStash kubectl plugin following the steps here.
If you are not familiar with how KubeStash backup and restore ZooKeeper, please check the following 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/zookeeper/backup/kubestash/logical/examples directory of kubedb/docs repository.

Backup ZooKeeper

KubeStash supports backups for ZooKeeper instances across different configurations, including Standalone and ZooKeeper Ensemble setups. In this demonstration, we’ll focus on a ZooKeeper using ZooKeeper Ensemble configuration. The backup and restore process is similar for Standalone configuration.

This section will demonstrate how to backup a ZooKeeper. Here, we are going to deploy a ZooKeeper using KubeDB. Then, we are going to backup this into a s3 bucket. Finally, we are going to restore the backup up data into another ZooKeeper.

Deploy Sample ZooKeeper

Let’s deploy a sample ZooKeeper and insert some data into it.

Create ZooKeeper CR:

Below is the YAML of a sample ZooKeeper CR that we are going to create for this tutorial:

apiVersion: kubedb.com/v1alpha2
kind: ZooKeeper
metadata:
  name: sample-zookeeper
  namespace: demo
spec:
  version: "3.8.3"
  adminServerPort: 8080
  replicas: 3
  storage:
    resources:
      requests:
        storage: "1Gi"
    accessModes:
      - ReadWriteOnce
  deletionPolicy: "WipeOut"

Create the above ZooKeeper CR,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/zookeeper/backup/kubestash/logical/examples/sample-zookeeper.yaml
zookeeper.kubedb.com/sample-zookeeper created

KubeDB will deploy a ZooKeeper according to the above specification. It will also create the necessary Secrets and Services to access.

Let’s check if the zookeeper is ready to use,

$ kubectl get zk -n demo sample-zookeeper
NAME               VERSION   STATUS   AGE
sample-zookeeper   8.3.3     Ready    5m1s

The zookeeper is Ready. Verify that KubeDB has created a Secret and a Service for this zookeeper using the following commands,

$ kubectl get secret -n demo 
NAME                           TYPE                       DATA   AGE
sample-zookeeper-auth          kubernetes.io/basic-auth   2      5m20s

$ kubectl get service -n demo -l=app.kubernetes.io/instance=sample-zookeeper
NAME                           TYPE         CLUSTER-IP        EXTERNAL-IP     PORT(S)                      AGE
sample-zookeeper               ClusterIP    10.128.65.175     <none>          2181/TCP                     5m55s
sample-zookeeper-pods          ClusterIP    None              <none>          2181/TCP,2888/TCP,3888/TCP   5m55s
sample-zookeeper-admin-server  ClusterIP    10.128.163.169    <none>          8080/TCP                     5m55s

Here, we have to use service sample-zookeeper and secret sample-zookeeper-auth to connect with the zookeeper. KubeDB creates an AppBinding CR that holds the necessary information to connect with the zookeeper.

Verify AppBinding:

Verify that the AppBinding has been created successfully using the following command,

$ kubectl get appbindings -n demo
NAME                       TYPE                   VERSION    AGE
sample-zookeeper           kubedb.com/zookeeper   3.8.3      9m30s

Let’s check the YAML of the above AppBinding,

$ kubectl get appbindings -n demo sample-zookeeper -o yaml

apiVersion: appcatalog.appscode.com/v1alpha1
kind: AppBinding
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"kubedb.com/v1alpha2","kind":"ZooKeeper","metadata":{"annotations":{},"name":"sample-zookeeper","namespace":"demo"},"spec":{"adminServerPort":8080,"deletionPolicy":"WipeOut","replicas":5,"storage":{"accessModes":["ReadWriteOnce"],"resources":{"requests":{"storage":"1Gi"}}},"version":"3.8.3"}}      
  creationTimestamp: "2024-09-12T10:40:48Z"
  generation: 2
  labels:
    app.kubernetes.io/component: database
    app.kubernetes.io/instance: sample-zookeeper
    app.kubernetes.io/managed-by: kubedb.com
    app.kubernetes.io/name: zookeepers.kubedb.com
  name: sample-zookeeper
  namespace: demo
  ownerReferences:
    - apiVersion: kubedb.com/v1alpha2
      blockOwnerDeletion: true
      controller: true
      kind: ZooKeeper
      name: sample-zookeeper
      uid: 6d41f283-1a60-45a2-a529-076a09f21ec2
  resourceVersion: "481401"
  uid: db007231-78f1-4ce8-8d2f-adff7d446095
spec:
  appRef:
    apiGroup: kubedb.com
    kind: ZooKeeper
    name: sample-zookeeper
    namespace: demo
  clientConfig:
    service:
      name: sample-zookeeper
      port: 2181
      scheme: http
  secret:
    name: sample-zookeeper-auth
  type: kubedb.com/zookeeper
  version: 3.8.3

KubeStash uses the AppBinding CR to connect with the target database. It requires the following two fields to set in AppBinding’s .spec section.

Here,

.spec.clientConfig.service.name specifies the name of the Service that connects to the database.
.spec.secret specifies the name of the Secret that holds necessary credentials to access the database.
.spec.type specifies the types of the app that this AppBinding is pointing to. KubeDB generated AppBinding follows the following format: <app group>/<app resource type>.

Insert Sample Data:

Now, we are going to exec into one of the database pod and create some sample data. At first, find out the database Pod using the following command,

$ kubectl get pods -n demo --selector="app.kubernetes.io/instance=sample-zookeeper" 
NAME                 READY   STATUS    RESTARTS   AGE
sample-zookeeper-0   2/2     Running   0          16m
sample-zookeeper-1   2/2     Running   0          13m
sample-zookeeper-2   2/2     Running   0          13m

Now, let’s exec into the pod and create a directory,

$ kubectl exec -it -n demo sample-zookeeper-0 -- sh

Type "help" for help.

# Check if Zookeeper server is running and healthy
$ echo ruok | nc localhost 2181
imok

# Create a znode named /hello-dir with the data "hello-message"
$ zkCli.sh create /hello-dir hello-messege
Connecting to localhost:2181
...
Connection Log Messeges
...
Created /hello-dir

# exit from the pod
/ $ exit

Now, we are ready to backup the data.

Prepare Backend

We are going to store our backed up data into a S3 bucket. We have to create a Secret with necessary credentials and a BackupStorage CR to use this backend. If you want to use a different backend, please read the respective backend configuration doc from here.

Create Secret:

Let’s create a secret called s3-secret with access credentials to our desired s3 bucket,

$ echo -n '<your-aws-access-key-id-here>' > AWS_ACCESS_KEY_ID
$ echo -n '<your-aws-secret-access-key-here>' > AWS_SECRET_ACCESS_KEY
$ kubectl create secret generic -n demo s3-secret \
    --from-file=./AWS_ACCESS_KEY_ID \
    --from-file=./AWS_SECRET_ACCESS_KEY
secret/s3-secret created

Create BackupStorage:

Now, create a BackupStorage using this secret. Below is the YAML of BackupStorage CR we are going to create,

apiVersion: storage.kubestash.com/v1alpha1
kind: BackupStorage
metadata:
  name: s3-storage
  namespace: demo
spec:
  storage:
    provider: s3
    s3:
      endpoint: ap-south-1.linodeobjects.com
      bucket: kubestash-zk
      region: ap-south-1
      prefix: sep4
      secretName: s3-secret
  usagePolicy:
    allowedNamespaces:
      from: All
  deletionPolicy: WipeOut

Let’s create the BackupStorage we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/zookeeper/backup/kubestash/logical/examples/backupstorage.yaml
backupstorage.storage.kubestash.com/s3-storage created

Now, we are ready to backup our data to our desired backend.

Create RetentionPolicy:

Now, let’s create a RetentionPolicy 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

Let’s create the above RetentionPolicy,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/zookeeper/backup/kubestash/logical/examples/retentionpolicy.yaml
retentionpolicy.storage.kubestash.com/demo-retention created

Backup

We have to create a BackupConfiguration targeting respective sample-zookeeper ZooKeeper. Then, KubeStash will create a CronJob for each session to take periodic backup of that database.

At first, we need to create a secret with a Restic password for backup data encryption.

Create Secret:

Let’s create a secret called 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

Below is the YAML for BackupConfiguration CR to backup the sample-zookeeper that we have deployed earlier,

apiVersion: core.kubestash.com/v1alpha1
kind: BackupConfiguration
metadata:
  name: sample-zookeeper-backup
  namespace: demo
spec:
  target:
    apiGroup: kubedb.com
    kind: ZooKeeper
    name: sample-zookeeper
    namespace: demo
  backends:
    - name: s3-backend
      storageRef:
        name: s3-storage
        namespace: demo
      retentionPolicy:
        name: demo-retention
        namespace: demo
  sessions:
    - name: frequent-backup
      scheduler:
        schedule: "*/5 * * * *"
        jobTemplate:
          backoffLimit: 1
      repositories:
        - name: s3-zookeeper-repo
          backend: s3-backend
          directory: /zookeeper
          encryptionSecret:
            name: encrypt-secret
            namespace: demo
      addon:
        name: zookeeper-addon
        tasks:
          - name: logical-backup

.spec.sessions[*].schedule specifies that we want to backup the database at 5 minutes interval.
.spec.target refers to the targeted sample-zookeeper ZooKeeper that we created earlier.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/zookeeper/kubestash/logical/examples/backupconfiguration.yaml
backupconfiguration.core.kubestash.com/sample-zookeeper-backup 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                      PHASE   PAUSED   AGE
sample-zookeeper-backup   Ready            2m50s

Additionally, we can verify that the Repository specified in the BackupConfiguration has been created using the following command,

$ kubectl get repo -n demo
NAME                  INTEGRITY   SNAPSHOT-COUNT   SIZE     PHASE   LAST-SUCCESSFUL-BACKUP   AGE
s3-zookeeper-repo                 0                0 B      Ready                            3m

KubeStash keeps the backup for Repository YAMLs. If we navigate to the s3 bucket, we will see the Repository YAML stored in the demo/zookeeper directory.

Verify CronJob:

It will also create a CronJob with the schedule specified in spec.sessions[*].scheduler.schedule field of BackupConfiguration CR.

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

$ kubectl get cronjob -n demo
NAME                                             SCHEDULE      SUSPEND   ACTIVE   LAST SCHEDULE   AGE
trigger-sample-zookeeper-backup-frequent-backup   */5 * * * *             0        2m45s           3m25s

Verify BackupSession:

KubeStash triggers an instant backup as soon as the BackupConfiguration is ready. After that, backups are scheduled according to the specified schedule.

$ kubectl get backupsession -n demo -w
NAME                                                 INVOKER-TYPE          INVOKER-NAME               PHASE       DURATION   AGE
sample-zookeeper-backup-frequent-backup-1726572962   BackupConfiguration   sample-zookeeper-backup    Succeeded              7m22s

We can see from the above output that the backup session has succeeded. Now, we are going to verify whether the backed up data has been stored in the backend.

Verify Backup:

Once a backup is complete, KubeStash will update the respective Repository CR to reflect the backup. Check that the repository sample-zookeeper-backup has been updated by the following command,

$ kubectl get repository -n demo s3-zookeeper-repo
NAME                  INTEGRITY   SNAPSHOT-COUNT   SIZE    PHASE   LAST-SUCCESSFUL-BACKUP   AGE
s3-zookeeper-repo     true        1                806 B   Ready   8m27s                    9m18s

At this moment we have one Snapshot. Run the following command to check the respective Snapshot which represents the state of a backup run for an application.

$ kubectl get snapshots -n demo -l=kubestash.com/repo-name=s3-zookeeper-repo
NAME                                                                   REPOSITORY          SESSION           SNAPSHOT-TIME          DELETION-POLICY   PHASE       AGE
s3-zookeeper-repo-sample-zookeeper-backup-frequent-backup-1726572962   s3-zookeeper-repo   frequent-backup   2024-01-23T13:10:54Z   Delete            Succeeded   16h

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 target Database or Repository.

If we check the YAML of the Snapshot, we can find the information about the backed up components of the Database.

$ kubectl get snapshots -n demo s3-zookeeper-repo-sample-zookeeper-backup-frequent-backup-1726572962 -oyaml

apiVersion: storage.kubestash.com/v1alpha1
kind: Snapshot
metadata:
  creationTimestamp: "2024-09-04T11:30:00Z"
  finalizers:
  - kubestash.com/cleanup
  generation: 1
  labels:
    kubestash.com/app-ref-kind: ZooKeeper
    kubestash.com/app-ref-name: sample-zookeeper
    kubestash.com/app-ref-namespace: demo
    kubestash.com/repo-name: s3-zookeeper-repo
  annotations:
    kubedb.com/db-version: "3.8.3"
  name: s3-zookeeper-repo-sample-zookeeper-backup-frequent-backup-1726572962
  namespace: demo
  ownerReferences:
  - apiVersion: storage.kubestash.com/v1alpha1
    blockOwnerDeletion: true
    controller: true
    kind: Repository
    name: s3-zookeeper-repo
    uid: dd7e2387-227d-4b89-9489-d6255535e322
  resourceVersion: "1226490"
  uid: dd7e2387-227d-4b89-9489-d6255535e322
spec:
  appRef:
    apiGroup: kubedb.com
    kind: ZooKeeper
    name: sample-zookeeper
    namespace: demo
  backupSession: sample-zookeeper-backup-frequent-backup-1726572962
  deletionPolicy: Delete
  repository: s3-zookeeper-repo
  session: frequent-backup
  snapshotID: 01J7ZW9ANMT1GAG6NP68N6Q0MJ
  type: FullBackup
  version: v1
status:
  components:
    dump:
      driver: Restic
      duration: 11.526138009s
      integrity: true
      path: repository/v1/frequent-backup/dump
      phase: Succeeded
      resticStats:
      - hostPath: /kubestash-interim/data
        id: cd20fca1a2bf6a97e669cb9eacdc74a312a08266da92b9d687aad88841e1205d
        size: 3.345 KiB
        uploaded: 299 B
      size: 2.202 KiB
  conditions:
  - lastTransitionTime: "2024-09-04T11:30:00Z"
    message: Recent snapshot list updated successfully
    reason: SuccessfullyUpdatedRecentSnapshotList
    status: "True"
    type: RecentSnapshotListUpdated
  - lastTransitionTime: "2024-09-04T11:30:32Z"
    message: Metadata uploaded to backend successfully
    reason: SuccessfullyUploadedSnapshotMetadata
    status: "True"
    type: SnapshotMetadataUploaded
  integrity: true
  phase: Succeeded
  size: 2.201 KiB
  snapshotTime: "2024-09-04T11:30:00Z"
  totalComponents: 1

KubeStash uses zk-dump-go to perform backups of target ZooKeeper. Therefore, the component name for logical backups is set as dump.

Now, if we navigate to the s3 bucket, we will see the backed up data stored in the demo/zookeeper/repository/v1/frequent-backup/dump directory. KubeStash also keeps the backup for Snapshot YAMLs, which can be found in the demo/zookeeper/snapshots directory.

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

Restore

In this section, we are going to restore the database from the backup we have taken in the previous section. We are going to deploy a new database and initialize it from the backup.

Now, we have to deploy the restored database similarly as we have deployed the original sample-zookeeper. However, this time there will be the following differences:

We are going to specify .spec.init.waitForInitialRestore field that tells KubeDB to wait for first restore to complete before marking this database is ready to use.

Below is the YAML for ZooKeeper CR we are going deploy to initialize from backup,

apiVersion: kubedb.com/v1alpha2
kind: ZooKeeper
metadata:
  name: restored-zookeeper
  namespace: demo
spec:
  version: "3.8.3"
  adminServerPort: 8080
  replicas: 3
  storage:
    resources:
      requests:
        storage: "1Gi"
    accessModes:
      - ReadWriteOnce
  deletionPolicy: "WipeOut"

Let’s create the above database,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/zookeeper/backup/kubestash/logical/examples/restored-zookeeper.yaml
zookeeper.kubedb.com/restored-zookeeper created

If you check the database status, you will see it is stuck in Provisioning state.

$ kubectl get zookeeper -n demo restored-zookeeper
NAME                 VERSION   STATUS         AGE
restored-zookeeper   3.8.3     Provisioning   61s

Create RestoreSession:

Now, we need to create a RestoreSession CR pointing to targeted ZooKeeper.

Below, is the contents of YAML file of the RestoreSession object that we are going to create to restore backed up data into the newly created ZooKeeper named restored-zookeeper.

apiVersion: core.kubestash.com/v1alpha1
kind: RestoreSession
metadata:
  name: sample-zookeeper-restore
  namespace: demo
spec:
  target:
    apiGroup: kubedb.com
    kind: ZooKeeper
    namespace: demo
    name: restored-zookeeper
  dataSource:
    repository: s3-zookeeper-repo
    snapshot: latest
    encryptionSecret:
      name: encrypt-secret
      namespace: demo
  addon:
    name: zookeeper-addon
    tasks:
      - name: logical-backup-restore

Here,

.spec.target refers to the newly created restored-zookeeper ZooKeeper object to where we want to restore backup data.
.spec.dataSource.repository specifies the Repository object that holds the backed up data.
.spec.dataSource.snapshot specifies to restore from latest Snapshot.

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

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2024.9.30/docs/guides/zookeeper/backup/kubestash/logical/examples/restoresession.yaml
restoresession.core.kubestash.com/sample-zookeeper-restore created

Once, you have created the RestoreSession object, KubeStash will create restore Job. Run the following command to watch the phase of the RestoreSession object,

$ watch kubectl get restoresession -n demo
Every 2.0s: kubectl get restores... AppsCode-PC-03: Wed Aug 21 10:44:05 2024
NAME                      REPOSITORY          FAILURE-POLICY   PHASE       DURATION   AGE
sample-zookeeper-restore   gcs-zookeeper-repo                    Succeeded   7s         116s

The Succeeded phase means that the restore process has been completed successfully.

Verify Restored Data:

In this section, we are going to verify whether the desired data has been restored successfully. We are going to connect to the database server and check whether the database and the table we created earlier in the original database are restored.

At first, check if the database has gone into Ready state by the following command,

$ kubectl get zookeeper -n demo restored-zookeeper
NAME                 VERSION   STATUS   AGE
restored-zookeeper   8.3.1      Ready    6m31s

Now, find out the database Pod by the following command,

$ kubectl get pods -n demo --selector="app.kubernetes.io/instance=restored-zookeeper"
NAME                             READY   STATUS      RESTARTS   AGE
restored-zookeeper-0             2/2     Running     0          6m7s
restored-zookeeper-1             2/2     Running     0          6m1s
restored-zookeeper-2             2/2     Running     0          5m55s

Now, lets exec one of the Pod and verify restored data.

$ kubectl exec -it -n demo restored-zookeeper-0 -- sh

Type "help" for help.

# Check if Zookeeper server is running and healthy
$ echo ruok | nc localhost 2181
imok

# List all znodes from the root directory
$ zkCli.sh ls /
Connecting to localhost:2181
...
Connection Log Messeges
...
[hello-dir]

# Verify the data stored in the /hello-dir znode
$ zkCli.sh get /hello-dir
Connecting to localhost:2181
...
Connection Log Messeges
...
hello-messege

# exit from the pod
/ $ exit

So, from the above output, we can see the demo database we had created in the original database sample-zookeeper has been restored in the restored-zookeeper.

Cleanup

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

kubectl delete backupconfigurations.core.kubestash.com  -n demo sample-zookeeper-backup
kubectl delete restoresessions.core.kubestash.com -n demo restore-sample-zookeeper
kubectl delete retentionpolicies.storage.kubestash.com -n demo demo-retention
kubectl delete backupstorage -n demo s3-storage
kubectl delete secret -n demo s3-secret
kubectl delete secret -n demo encrypt-secret
kubectl delete zookeeper -n demo restored-zookeeper
kubectl delete zookeeper -n demo sample-zookeeper

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