Deploying a Redis Sharding Cluste (Cluster Mode) with KubeBlocks

Redis Cluster distributes data across multiple nodes (shards) using hash-based partitioning, allowing horizontal scaling for both reads and writes.

Use Cases

• Large-scale applications requiring high throughput.
• Distributed caching and session storage.
• Write-heavy workloads (e.g., real-time analytics).

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 Sharding Cluster

To create a redis sharding cluster (cluster mode) with 3 shards, and 2 replica for each shard:

apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: redis-sharding
  namespace: demo
spec:
  terminationPolicy: Delete
  shardings:
  - name: shard
    shards: 3
    template:
      name: redis
      componentDef: redis-cluster-7
      disableExporter: true
      replicas: 2
      resources:
        limits:
          cpu: '1'
          memory: 1Gi
        requests:
          cpu: '1'
          memory: 1Gi
      serviceVersion: 7.2.4
      volumeClaimTemplates:
      - name: data
        spec:
          accessModes:
          - ReadWriteOnce
          resources:
            requests:
              storage: 20Gi
      services:
      - name: redis-advertised # This is a per-pod svc, and will be used to parse advertised endpoints
        podService: true
        #  - NodePort
        #  - LoadBalancer
        serviceType: NodePort

Key Configuration Details:

• shardings: Specifies a list of ShardingSpec objects that configure the sharding topology for components of a Cluster.

Verifying the Deployment

Check the Cluster Status

Once the cluster is deployed, check its status:

kubectl get cluster redis-sharding  -n demo -w

Expected Output:

NAME             CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS    AGE
redis-sharding                        Delete               Running   103s

Verify Component and Pod Status

Get all componets working for this cluster:

kubectl get cmp -l app.kubernetes.io/instance=redis-sharding -n demo

Expected Output:

NAME                       DEFINITION                      SERVICE-VERSION   STATUS    AGE
redis-sharding-shard-5cd   redis-cluster-7-1.0.0           7.2.4             Running   2m34s
redis-sharding-shard-drg   redis-cluster-7-1.0.0           7.2.4             Running   2m34s
redis-sharding-shard-tgf   redis-cluster-7-1.0.0           7.2.4             Running   2m34s

Each component stands for a shard, with hash id as suffix.

Check pods and their roles

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

Expected Output:

NAME                         READY   STATUS    RESTARTS   AGE     ROLE
redis-sharding-shard-5cd-0   2/2     Running   0          3m55s   primary
redis-sharding-shard-5cd-1   2/2     Running   0          3m35s   secondary
redis-sharding-shard-drg-0   2/2     Running   0          3m53s   primary
redis-sharding-shard-drg-1   2/2     Running   0          3m35s   secondary
redis-sharding-shard-tgf-0   2/2     Running   0          3m54s   primary
redis-sharding-shard-tgf-1   2/2     Running   0          3m36s   secondary

There are in-total six replicas in the cluster, two (one primarily and one secondary) for each component.

Cleanup

To remove all resources created during this tutorial:

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