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Create and connect to an ApeCloud MySQL cluster

This tutorial shows how to create and connect to an ApeCloud MySQL cluster.

Create a MySQL cluster​

Before you start​

  • Install kbcli if you want to create and connect a MySQL cluster by kbcli.

  • Install KubeBlocks.

  • Check whether the ApeCloud MySQL Addon is enabled. The ApeCloud MySQL Addon is enabled by KubeBlocks by default. If you disable it when installing KubeBlocks,enable it first.

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

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

    Make sure the apecloud-mysql cluster definition is installed.

    kubectl get clusterdefinition apecloud-mysql
    >
    NAME             TOPOLOGIES   SERVICEREFS   STATUS      AGE
    apecloud-mysql                              Available   85m

    View all available versions for creating a cluster.

    kubectl get clusterversions -l clusterdefinition.kubeblocks.io/name=apecloud-mysql
    >
    NAME                CLUSTER-DEFINITION   STATUS      AGE
    ac-mysql-8.0.30     apecloud-mysql       Available   85m

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

    kubectl create namespace demo

Create a cluster​

KubeBlocks supports creating two types of ApeCloud MySQL clusters: Standalone and RaftGroup 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 RaftGroup Cluster, which creates a cluster with three replicas. To ensure high availability, all replicas are distributed on different nodes by default.

  1. Create an ApeCloud MySQL cluster.

    KubeBlocks implements a Cluster CRD to define a cluster. Here is an example of creating a RaftGroup Cluster.

    If you only have one node for deploying a RaftGroup 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: apecloud-mysql
      topology: apecloud-mysql
      componentSpecs:
        - name: mysql
          serviceVersion: "8.0.30"
          disableExporter: false
          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 apecloud-mysql to create a ApeCloud-MySQL 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. The valid option for ApeCloud MySQL is 8.0.30.
    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. ApeCloud-MySQL prefers ODD numbers like [1, 3, 5, 7].
    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.

    KubeBlocks operator watches for the Cluster CRD and creates the cluster and all dependent resources. You can get all the resources created by the cluster by running the command below.

    kubectl get all,secret,rolebinding,serviceaccount -l app.kubernetes.io/instance=mycluster -n demo

    Run the following command to view the details of the created ApeCloud MySQL cluster:

    kubectl get cluster mycluster -n demo -o yaml

  2. Verify whether this cluster is created successfully.

    kubectl get cluster mycluster -n demo
    >
    NAME        CLUSTER-DEFINITION   VERSION           TERMINATION-POLICY   STATUS    AGE
    mycluster   apecloud-mysql       ac-mysql-8.0.30   Delete               Running   12m

Connect to an ApeCloud MySQL Cluster​

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

KubeBlocks operator creates a new Secret called mycluster-conn-credential to store the connection credential of the ApeCloud MySQL cluster. This secret contains the following keys:

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

  1. Run the command below to get the username and password for the kubectl exec command.

    kubectl get secrets -n demo mycluster-conn-credential -o jsonpath='{.data.username}' | base64 -d
    >
    root

    kubectl get secrets -n demo mycluster-conn-credential -o jsonpath='{.data.password}' | base64 -d
    >
    2gvztbvz

  2. Exec into the Pod mycluster-mysql-0 and connect to the database using username and password.

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

    mysql -uroot -p2gvztbvz

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