Restore a MySQL Cluster from Backup with Point-In-Time-Recovery(PITR) on KubeBlocks

This guide provides a step-by-step walk-through for restoring a MySQL cluster from an existing full backup in KubeBlocks, along with continuous binlog backups for Point-In-Time Recovery (PITR).

Prerequisites

Before proceeding, ensure the following:

• Environment Setup:
  • A Kubernetes cluster is up and running.
  • The kubectl CLI tool is configured to communicate with your cluster.
  • KubeBlocks CLI and KubeBlocks Operator are installed. Follow the installation instructions here.
• Namespace Preparation: To keep resources isolated, create a dedicated namespace for this tutorial:

kubectl create ns demo
namespace/demo created

Check Existing Backups

To perform a PITR restoration, both a full backup and continuous backup are required. Refer to the documentation to configure these backups if they are not already set up.

List available backups with the following command:

kubectl get backup -n demo

Expected Output:

NAME                                               POLICY                                      METHOD           REPO      STATUS      TOTAL-SIZE   DURATION   DELETION-POLICY   CREATION-TIME          COMPLETION-TIME        EXPIRATION-TIME
77a788fa-example-mysql-cluster-archive-binlog      example-mysql-cluster-mysql-backup-policy   archive-binlog   s3-repo   Running     2110030                 Delete            2025-03-04T02:28:55Z                          2025-04-03T02:28:55Z
example-mysql-cluster-xtrabackup-20250305000008    example-mysql-cluster-mysql-backup-policy   xtrabackup       s3-repo   Completed   3102161      18s        Delete            2025-03-05T00:00:11Z   2025-03-05T00:00:29Z   2025-04-04T00:00:29Z

• '77a788fa-example-mysql-cluster-archive-binlog': Continuous backup (binlog archive).
• 'example-mysql-cluster-xtrabackup-20250305000008': Full backup.

Create Restored Cluster

Create a new cluster with restoration configuration referencing the backup.

Apply the following YAML configuration:

kubectl apply -f - <<EOF
apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: example-mysql-cluster-restored
  namespace: demo
  annotations:
    kubeblocks.io/restore-from-backup: '{"mysql":{"name":"example-mysql-cluster-xtrabackup-20250305000008","namespace":"demo","volumeRestorePolicy":"Parallel",
"restoreTime":"2025-03-05T02:00:00Z"}}'
spec:
  terminationPolicy: Delete
  componentSpecs:
    - name: mysql
      componentDef: "mysql-8.0"
      serviceVersion: 8.0.35
      disableExporter: false
      replicas: 2
      resources:
        limits:
          cpu: '0.5'
          memory: 0.5Gi
        requests:
          cpu: '0.5'
          memory: 0.5Gi
      volumeClaimTemplates:
        - name: data
          spec:
            storageClassName: ""
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 20Gi
EOF

Perform Restoration via Ops API

Alternatively, use the Ops API to initiate the restoration process:

kubectl apply -f - <<EOF
apiVersion: operations.kubeblocks.io/v1alpha1
kind: OpsRequest
metadata:
  name: example-mysql-cluster-restore
  namespace: demo
spec:
  clusterName: example-mysql-cluster-restore
  force: false
  restore:
    backupName: example-mysql-cluster-xtrabackup-20250305000008
    backupNamespace: demo
    restorePointInTime: 2025-03-05T02:00:00Z
  type: Restore
EOF

Monitor Restoration Progress

Step 1: Watch Pod Initialization

kubectl get pods -n demo -w

Expected Workflow:

1. Data Preparation Pods:

restore-preparedata-XXXXX-<hash>   0/1     Init:0/1   0          6s
restore-preparedata-XXXXX-<hash>   1/1     Running    0          12s
restore-preparedata-XXXXX-<hash>   0/1     Completed 0          20s

These pods copy backup data to Persistent Volumes (PVCs).

2. MySQL Cluster Pods:

example-mysql-cluster-restored-mysql-0     0/4     Pending        0          0s
example-mysql-cluster-restored-mysql-0     4/4     Running        0          20s

After restoration, MySQL cluster pods initialize with the restored data and start the MySQL service.

Step 2: Verify Cluster Status

Check the status of the restored cluster:

kubectl get cluster example-mysql-cluster-restored -n demo

Successful Output:

NAME                    CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS    AGE
example-mysql-cluster-restored                        Delete               Running   97s

Cleanup

To remove all created resources, delete the MySQL cluster along with its namespace:

kubectl delete cluster example-mysql-cluster -n demo
kubectl delete cluster example-mysql-cluster-restored -n demo
kubectl delete ns demo

Summary

This guide demonstrated how to restore a MySQL cluster in KubeBlocks using a full backup and continuous binlog backup for Point-In-Time Recovery (PITR). Key steps included:

• Verifying available backups.
• Extracting encrypted system account credentials.
• Creating a new MySQL cluster with restoration configuration.
• Monitoring the restoration process.

With this approach, you can restore a MySQL cluster to a specific point in time, ensuring minimal data loss and operational continuity.