Setting Up a MySQL Cluster with Scheduled Backups in KubeBlocks

This guide demonstrates how to deploy a MySQL cluster using KubeBlocks and configure scheduled backups with retention in an S3 repository.

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

Deploy a MySQL Semi-Synchronous Cluster

KubeBlocks uses a declarative approach for managing MySQL clusters. Below is an example configuration for deploying a MySQL cluster with 2 nodes (1 primary, 1 replicas) in semi-synchronous mode and scheduled backups.

Cluster Configuration

kubectl apply -f - <<EOF
apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: example-mysql-cluster
  namespace: demo
spec:
  clusterDef: mysql
  topology: semisync
  terminationPolicy: WipeOut
  componentSpecs:
    - name: mysql
      serviceVersion: 8.0.35
      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
  backup:
    enabled: true
    retentionPeriod: 30d
    method: xtrabackup
    cronExpression: '0 0 * * *'
    repoName: s3-repo
EOF

Explanation of Key Fields

• terminationPolicy: WipeOut:
  • When set to 'WipeOut', deleting the cluster also deletes all associated data, including backups.
  • For production environments, it is recommended to use terminationPolicy: Delete, which retains backup data even after the cluster is deleted.
• backup.enabled: true: Enables scheduled backups for the cluster.
• method: xtrabackup: Specifies the backup tool to be used (e.g., Percona XtraBackup).
• cronExpression: '0 0 * * *': Configures the backup schedule to run daily at midnight (UTC).
• retentionPeriod: 30d: Retains backups for 30 days.
• repoName: s3-repo: Specifies the S3 repository for storing backups.

Verifying the Deployment

Monitor the cluster status until it transitions to Running:

kubectl get cluster example-mysql-cluster -n demo

Example Output:

NAME                             CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS    AGE
example-mysql-cluster   mysql                Delete               Running   38s

Once the status is Running, the MySQL cluster is successfully deployed.

Check the BackupSchedule Resource

KubeBlocks automatically creates a BackupSchedule resource when scheduled backups are enabled. Verify the configuration using the following command:

kubectl get backupschedule example-mysql-cluster-mysql-backup-schedule  -n demo -oyaml

Example Output:

apiVersion: dataprotection.kubeblocks.io/v1alpha1
kind: BackupSchedule
...
spec:
  backupPolicyName: example-mysql-cluster-mysql-backup-policy
  schedules:
    - backupMethod: xtrabackup
      cronExpression: 0 0 * * *
      enabled: true
      name: xtrabackup
      retentionPeriod: 30d

This confirms that the BackupSchedule resource is properly configured with the retention period and cron schedule.

Validate Backup in S3 Repository

After the scheduled backup task has been executed, verify the backup files in the configured S3 bucket with the following command:

TZ=":UTC" aws s3 ls s3://kubeblocks-backup-repo/ --recursive

Example Output:

2025-02-06 00:00:52    3087203 demo/example-mysql-cluster-5f46be4f-c9ac-414e-9d66-2dfe0a281b83/mysql/example-mysql-cluster-xtrabackup-20250206000001/example-mysql-cluster-xtrabackup-20250206000001.xbstream.zst
2025-02-06 00:01:03       5348 demo/example-mysql-cluster-5f46be4f-c9ac-414e-9d66-2dfe0a281b83/mysql/example-mysql-cluster-xtrabackup-20250206000001/kubeblocks-backup.json

Backup Files:

• Compressed Backup Data: 'example-mysql-cluster-xtrabackup-20250206000001.xbstream.zst'
• Backup Metadata: 'kubeblocks-backup.json'

Cleanup

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

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

Summary

In this guide:

• The backup was executed at midnight UTC (2025-02-06 00:00:52), as defined in the cronExpression field of the backup configuration.
• The backup files were successfully stored in the specified S3 repository. These include:
  • The compressed backup data file ('example-mysql-cluster-xtrabackup-20250206000001.xbstream.zst').
  • The metadata file ('kubeblocks-backup.json') which contains information about the backup.

By following this guide, you can automate regular backups for your MySQL clusters, ensuring data availability and recovery options.