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Deploy ClickHouse Operator and a ClickHouse Cluster on KubeSphere

ClickHouse is a column-oriented database management system (DBMS) for online analytical processing of queries (OLAP). RadonDB ClickHouse is a deeply customized ClickHouse cluster application maintaining ClickHouse cluster functions and featuring automated cluster management, data redistribution in clusters, and excellent performance with less cost.

This tutorial demonstrates how to deploy ClickHouse Operator and a ClickHouse Cluster on KubeSphere.

Prerequisites

  • You need to enable the OpenPitrix system.
  • You need to create a workspace, a project, and two user accounts (ws-admin and project-regular) for this tutorial. The account ws-admin must be granted the role of workspace-admin in the workspace, and the account project-regular must be invited to the project with the role of operator. This tutorial uses demo-workspace and demo-project for demonstration. If they are not ready, refer to Create Workspaces, Projects, Accounts and Roles.
  • You need to enable the gateway in your project to provide external access. If they are not ready, refer to Project Gateway.

Hands-on Lab

Step 1: Deploy ClickHouse Operator

  1. Log in to the KubeSphere Web console as admin, and use Kubectl from the Toolbox in the bottom-right corner to run the following command to install ClickHouse Operator. It is recommended that you have at least two worker nodes available in your cluster.

    kubectl apply -f https://raw.githubusercontent.com/radondb/radondb-clickhouse-kubernetes/master/clickhouse-operator-install.yml
    

    Note

    This command will install ClickHouse Operator in the namespace kube-system. Therefore, ClickHouse Operator only needs to be installed once in a Kubernetes cluster.
  2. You can see the expected output as below if the installation is successful.

    customresourcedefinition.apiextensions.k8s.io/clickhouseinstallations.clickhouse.qingcloud.com created
    customresourcedefinition.apiextensions.k8s.io/clickhouseinstallationtemplates.clickhouse.qingcloud.com created
    customresourcedefinition.apiextensions.k8s.io/clickhouseoperatorconfigurations.clickhouse.qingcloud.com created
    serviceaccount/clickhouse-operator created
    clusterrolebinding.rbac.authorization.k8s.io/clickhouse-operator-kube-system created
    configmap/etc-clickhouse-operator-files created
    configmap/etc-clickhouse-operator-confd-files created
    configmap/etc-clickhouse-operator-configd-files created
    configmap/etc-clickhouse-operator-templatesd-files created
    configmap/etc-clickhouse-operator-usersd-files created
    deployment.apps/clickhouse-operator created
    service/clickhouse-operator-metrics created
    
  3. You can run the following command to view the status of ClickHouse Operator resources.

    kubectl get all --selector=app=clickhouse-operator -n kube-system
    

    Expected output:

    NAME                                      READY   STATUS    RESTARTS   AGE
    pod/clickhouse-operator-6b8494c8f-tmkmn   2/2     Running   0          6m34s
       
    NAME                                  TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
    service/clickhouse-operator-metrics   ClusterIP   10.233.51.66   <none>        8888/TCP   6m34s
       
    NAME                                  READY   UP-TO-DATE   AVAILABLE   AGE
    deployment.apps/clickhouse-operator   1/1     1            1           6m34s
       
    NAME                                            DESIRED   CURRENT   READY   AGE
    replicaset.apps/clickhouse-operator-6b8494c8f   1         1         1       6m34s
    

Step 2: Add an app repository

  1. Log out of KubeSphere and log back in as ws-admin. In demo-workspace, go to App Repositories under App Management, and then click Add.

    add-repo

  2. In the dialog that appears, enter clickhouse for the app repository name and https://radondb.github.io/radondb-clickhouse-kubernetes/ for the repository URL. Click Validate to verify the URL and you will see a green check mark next to the URL if it is available. Click OK to continue.

    add-clickhouse

  3. Your repository displays in the list after successfully imported to KubeSphere.

    repo-added

Step 3: Deploy a ClickHouse Cluster

  1. Log out of KubeSphere and log back in as project-regular. In demo-project, go to Apps under Application Workloads and click Deploy New App.

    click-deploy-new-app

  2. In the dialog that appears, select From App Templates.

    from-app-templates

  3. On the new page that appears, select clickhouse from the drop-down list and then click clickhouse-cluster.

    clickhouse-cluster

  4. On the Chart Files tab, you can view the configuration and download the values.yaml file. Click Deploy to continue.

    chart-tab

  5. On the Basic Information page, confirm the app name, app version, and deployment location. Click Next to continue.

    basic-info

  6. On the App Configurations tab, you can change the YAML file to customize configurations. In this tutorial, click Deploy to use the default configurations.

    click-deploy

  7. After a while, you can see the app status shown as Running.

    app-running

Step 4: View ClickHouse Cluster status

  1. In Workloads under Application Workloads, click the StatefulSets tab and you can see the StatefulSets are up and running.

    statefulsets-running

  2. Click a single StatefulSet to go to its detail page. You can see the metrics in line charts over a period of time under the Monitoring tab.

    statefulset-monitoring

  3. In Pods under Application Workloads, you can see all the Pods are up and running.

    pods-running

  4. In Volumes under Storage, you can see the ClickHouse Cluster components are using persistent volumes.

    volumes

  5. Volume usage is also monitored. Click a volume item to go to its detail page. Here is an example of one of the data nodes.

    volume-status

  6. On the Overview page of the project, you can see a list of resource usage in the current project.

    project-overview

Step 5: Access the ClickHouse Cluster

  1. Log out of KubeSphere and log back in as admin. Hover your cursor over the hammer icon in the bottom-right corner and then select Kubectl.

  2. In the window that appears, run the following command and then navigate to the username and password of the ClickHouse cluster.

    kubectl edit chi clickho-749j8s -n demo-project
    

    get-username-password

    Note

    In the above command, clickho-749j8s is the ClickHouse application name and demo-project is the project name. Make sure you use your own application name and project name.
  3. Run the following command to access the ClickHouse cluster, and then you can use command like show databases to interact with it.

    kubectl exec -it chi-clickho-749j8s-all-nodes-0-0-0 -n demo-project -- clickhouse-client --user=clickhouse --password=c1ickh0use0perator
    

    use-clickhouse

    Note

    In the above command, chi-clickho-749j8s-all-nodes-0-0-0 is the Pod name and you can find it in Pods under Application Workloads. Make sure you use your own Pod name, project name, username and password.

Thanks for the feedback. If you have a specific question about how to use KubeSphere, ask it on Slack. Open an issue in the GitHub repo if you want to report a problem or suggest an improvement.