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Create and Connect to a Redis cluster

This tutorial shows how to create and connect to a Redis cluster.

Create a Redis cluster​

Before you start​

  • Install kbcli if you want to create a Redis cluster by kbcli.

  • Install KubeBlocks.

  • Make sure the Redis Addon is enabled. The Redis Addon is enabled by KubeBlocks by default. If you disable it when installing KubeBlocks, enable it first.

    kubectl get addons.extensions.kubeblocks.io redis
    >
    NAME      TYPE   VERSION   PROVIDER   STATUS    AGE
    redis     Helm                        Enabled   61m

  • View all the database types and versions available for creating a cluster.

    kubectl get clusterdefinition redis
    >
    NAME    TOPOLOGIES                                              SERVICEREFS   STATUS      AGE
    redis   replication,replication-twemproxy,standalone                          Available   16m
    kubectl get clusterversions -l clusterdefinition.kubeblocks.io/name=redis
    >
    NAME          CLUSTER-DEFINITION   STATUS      AGE
    redis-7.0.6   redis                Available   16m
    redis-7.2.4   redis                Available   16m

  • To keep things isolated, create a separate namespace called demo throughout this tutorial.

    kubectl create namespace demo
    >
    namespace/demo created

Create a cluster​

KubeBlocks supports creating two types of Redis clusters: Standalone and Replication Cluster. Standalone only supports one replica and can be used in scenarios with lower requirements for availability. For scenarios with high availability requirements, it is recommended to create a Replication Cluster, which supports automatic failover. To ensure high availability, Primary and Secondary are distributed on different nodes by default.

KubeBlocks implements a Cluster CRD to define a cluster. Here is an example of creating a Replication cluster. KubeBlocks also supports creating a Redis cluster in other modes. You can refer to the examples provided in the GitHub repository.

If you only have one node for deploying a Replication Cluster, configure the cluster affinity by setting spec.schedulingPolicy or spec.componentSpecs.schedulingPolicy. For details, you can refer to the API docs. But for a production environment, it is not recommended to deploy all replicas on one node, which may decrease the cluster availability.

cat <<EOF | kubectl apply -f -
apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: mycluster
  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
EOF
FieldDefinition
spec.terminationPolicyIt is the policy of cluster termination. Valid values are DoNotTerminate, Delete, WipeOut. For the detailed definition, you can refer to Termination Policy.
spec.clusterDefIt specifies the name of the ClusterDefinition to use when creating a Cluster. Note: DO NOT UPDATE THIS FIELD. The value must be redis to create a Redis Cluster.
spec.topologyIt specifies the name of the ClusterTopology to be used when creating the Cluster.
spec.componentSpecsIt is the list of ClusterComponentSpec objects that define the individual Components that make up a Cluster. This field allows customized configuration of each component within a cluster.
spec.componentSpecs.serviceVersionIt specifies the version of the Service expected to be provisioned by this Component. Valid options are [7.0.6,7.2.4].
spec.componentSpecs.disableExporterIt determines whether metrics exporter information is annotated on the Component's headless Service. Valid options are [true, false].
spec.componentSpecs.replicasIt specifies the number of replicas of the component.
spec.componentSpecs.resourcesIt specifies the resources required by the Component.
spec.componentSpecs.volumeClaimTemplatesIt specifies a list of PersistentVolumeClaim templates that define the storage requirements for the Component.
spec.componentSpecs.volumeClaimTemplates.nameIt refers to the name of a volumeMount defined in componentDefinition.spec.runtime.containers[*].volumeMounts.
spec.componentSpecs.volumeClaimTemplates.spec.storageClassNameIt is the name of the StorageClass required by the claim. If not specified, the StorageClass annotated with storageclass.kubernetes.io/is-default-class=true will be used by default.
spec.componentSpecs.volumeClaimTemplates.spec.resources.storageYou can set the storage size as needed.

For more API fields and descriptions, refer to the API Reference.

Run the following command to see the created Redis cluster object:

kubectl get cluster mycluster -n demo -o yaml

Connect to a Redis Cluster​

You can use kubectl exec to exec into a Pod and connect to a database.

KubeBlocks operator has created a new Secret called mycluster-conn-credential to store the connection credential of the Redis cluster. This secret contains the following keys:

  • username: the root username of the Redis cluster.
  • password: the password of the root user.
  • port: the port of the Redis cluster.
  • host: the host of the Redis cluster.
  • endpoint: the endpoint of the Redis cluster and it is the same as host:port.

  1. Get the username and password for the kubectl exec command.

    kubectl get secrets -n demo mycluster-redis-account-default -o jsonpath='{.data.username}' | base64 -d
    >
    default

    kubectl get secrets -n demo mycluster-redis-account-default -o jsonpath='{.data.password}' | base64 -d
    >
    5bv7czc4

  2. Exec into the pod mycluster-redis-0 and connect to the database using username and password.

    kubectl exec -ti -n demo mycluster-redis-0 -- bash

    root@mycluster-redis-0:/# redis-cli -a 5bv7czc4  --user default

For the detailed database connection guide, refer to Connect database.