Using kubernetes clickhouse.altinity.com with cluster

Question

Pulumi · Accepted Answer

To deploy a ClickHouse cluster on Kubernetes, you'll be using Helm charts to install ClickHose. Helm is a package manager for Kubernetes that simplifies the deployment and management of applications on Kubernetes clusters. There is a popular Helm chart provided by Altinity, the company behind ClickHouse, which simplifies the deployment.

Firstly, you need to set up your Kubernetes cluster where ClickHouse will be installed. You can do it with any cloud provider or on your local machine using tools like Minikube. Once the Kubernetes cluster is ready, your next step is to install Helm and add the repository for the ClickHouse Helm charts.

After adding the Helm repository, you can customize the deployment by creating a values.yaml file, where you can specify various settings like the number of replicas, resource allocations, storage classes, etc. Finally, you deploy ClickHouse by running `helm install`, pointing it to your values.yaml file and the ClickHouse chart.

Below is an example Pulumi program written in TypeScript that demonstrates how to add a Helm chart for ClickHouse into an existing Kubernetes cluster. It assumes that you already have a Kubernetes cluster configured in your environment and `kubectl` is set up to communicate with it.

```typescript
import * as kubernetes from "@pulumi/kubernetes";

// Create a Kubernetes provider instance that uses our existing cluster configuration.
const k8sProvider = new kubernetes.Provider("k8s", {
    kubeconfig: `your-kubeconfig-file-contents`
});

// Add the Altinity ClickHouse Operator Helm chart repo.
const clickhouseOperatorRepo = new kubernetes.helm.v3.Chart("clickhouse-operator", {
    chart: "clickhouse-operator",
    version: "0.16.0",  // Use the version of the chart that you want to install.
    fetchOpts:{
        repo: "https://altinity.github.io/clickhouse-operator/",
    },
}, { provider: k8sProvider });

// Deploy ClickHouse cluster using the Altinity ClickHouse Operator Helm chart.
const clickhouseCluster = new kubernetes.helm.v3.Chart("clickhouse-cluster", {
    chart: "clickhouse",
    version: "0.1.0",  // Replace with the appropriate chart version.
    fetchOpts:{
        repo: "https://altinity.github.io/clickhouse-operator/",
    },
    values: {
        // Specify your customization here. For example, you can set the number of shards, replicas, etc.
        // The structure of the options will depend on the specific Helm chart's values.yaml file.
        // Refer to the Altinity ClickHouse Operator documentation for configuration details.
    },
}, { provider: k8sProvider });

// Export the URL for the ClickHouse service, so we can access it from outside the cluster.
export const clickhouseServiceUrl = clickhouseCluster.getResourceProperty("v1/Service", "clickhouse-cluster-clickhouse", "status");
```

In this TypeScript program, you can see that we first establish a connection to our Kubernetes cluster by specifying the `kubeconfig` content. Then, we add the Altinity ClickHouse Operator repository and install it into our cluster. After that, we deploy a ClickHouse cluster with our customized values.

Please remember to replace `"your-kubeconfig-file-contents"` with the actual contents of your kubeconfig file that grants access to your Kubernetes cluster. Also, customize the `values` field according to your deployment requirements, such as scaling and storage options.

This program can then be run with the Pulumi CLI by using `pulumi up` which will deploy these resources to your Kubernetes cluster. After deployment, you can interact with the ClickHouse Service to manage or query your databases.

Keep in mind that you would need to have Pulumi installed on your system along with the dependencies that the Pulumi program requires. If it's your first time with Pulumi, you would need to perform the initial setup including logging into the Pulumi service with `pulumi login` and creating a new stack with `pulumi stack init`.

I hope this gives you a good starting point for managing a ClickHouse cluster on Kubernetes with Pulumi and Helm in TypeScript!