Deploying a Redis Replication Cluster with KubeBlocks

Redis Replication involves a primary (master) node that handles writes and one or more replica (slave) nodes that replicate data from the master for read scaling and failover.

Use Cases

• Read-heavy applications (e.g., analytics workload).
• High-availability setups with Redis Sentinel for automatic failover.

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

Deploying the Redis Replication Cluster

apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: redis-replication
  namespace: demo
spec:
  terminationPolicy: Delete
  clusterDef: redis
  topology: replication
  componentSpecs:
    - name: redis
      serviceVersion: "7.2.4"
      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
    - name: redis-sentinel
      replicas: 3
      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

Key Configuration Details:

• clusterDef: redis: Specifies the ClusterDefinition CR for the cluster.
• topology: replication: Configures the cluster to use replication topology.
• componentSpecs: Defines the components in the cluster:
  • Component 'redis':
    • serviceVersion: 7.2.4: Specifies the version of the Redis service to be deployed.
  • Component 'redis-sentinel':
    • Redis Sentinel is a high availability solution for Redis. Recommended to deploy 3 replica for high availability.

Verifying the Deployment

Check the Cluster Status

Once the cluster is deployed, check its status:

kubectl get cluster redis-replication  -n demo -w

Expected Output:

NAME                CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS    AGE
redis-replication   redis                Delete               Running   66s

Verify Component and Pod Status

kubectl get component redis-replication-redis -n demo

Expected Output:

NAME                      DEFINITION              SERVICE-VERSION   STATUS    AGE
redis-replication-redis   redis-7-1.0.0           7.2.4             Running   90s

Check pods and their roles

kubectl get pods -l app.kubernetes.io/instance=redis-replication -L  kubeblocks.io/role -n demo

Expected Output:

NAME                                 READY   STATUS    RESTARTS   AGE     ROLE
redis-replication-redis-0            3/3     Running   0          3m38s   primary
redis-replication-redis-1            3/3     Running   0          3m16s   secondary
redis-replication-redis-sentinel-0   2/2     Running   0          4m35s
redis-replication-redis-sentinel-1   2/2     Running   0          4m17s
redis-replication-redis-sentinel-2   2/2     Running   0          3m59s

Cleanup

To remove all resources created during this tutorial:

kubectl delete cluster redis-replication -n demo
kubectl delete ns demo