Using kubernetes traefik.containo.us with clickhouse.altinity.com

Question

Pulumi · Accepted Answer

In this guide, you'll learn how to deploy a ClickHouse database within a Kubernetes cluster and expose it securely using Traefik as an Ingress controller. ClickHouse is an open-source column-oriented database management system that allows for generating analytical data reports in real-time, and Traefik is a modern HTTP reverse proxy and load balancer that makes deploying microservices easy.

To achieve this, you will be using Pulumi, an Infrastructure as Code tool that enables you to create, deploy, and manage infrastructure using code written in general-purpose programming languages.

Here's what we'll do:

1. Create a Kubernetes namespace for ClickHouse.
2. Deploy ClickHouse to the Kubernetes cluster using the official ClickHouse operator.
3. Set up Traefik as an Ingress controller to route external traffic to ClickHouse.

Let's dive into the Pulumi TypeScript code:

```typescript
import * as k8s from "@pulumi/kubernetes";

// Step 1: Creating a Kubernetes namespace for ClickHouse
const clickHouseNamespace = new k8s.core.v1.Namespace("clickhouse-namespace", {
  metadata: { name: "clickhouse" },
});

// Note: The official ClickHouse operator and Custom Resource Definitions (CRDs) need to be
// installed manually or using a dedicated Pulumi resource prior to deploying the ClickHouse cluster,
// as Pulumi does not manage CRDs directly in a safe way due to the risk of data loss.

// Step 2: Deploying ClickHouse using the official chart
const clickHouseRelease = new k8s.helm.v3.Release("clickhouse-release", {
  name: "clickhouse",
  chart: "clickhouse/clickhouse",
  version: "1.0.0", // Specify the desired chart version
  namespace: clickHouseNamespace.metadata.name,
  // Set any values required for the ClickHouse Helm chart here
  // values can be found in the ClickHouse chart's values.yaml file
  values: {
    persistence: {
      enabled: true,
      size: "20Gi",
    },
    // Other configuration options...
  },
}, { dependsOn: clickHouseNamespace });

// Step 3: Setting up Traefik as an Ingress Controller
// Note: Make sure that Traefik Helm chart or Traefik Operator is installed in your cluster.
// Here we assume that Traefik is already running and properly configured to handle Ingress resources.
const clickHouseIngress = new k8s.networking.v1.Ingress("clickhouse-ingress", {
  metadata: {
    namespace: clickHouseNamespace.metadata.name,
    annotations: {
      "kubernetes.io/ingress.class": "traefik", // Ensure this matches your Traefik Ingress class
      // Additional Traefik-specific annotations can be added here, if needed
    },
  },
  spec: {
    rules: [{
      http: {
        paths: [{
          path: "/clickhouse",
          pathType: "Prefix",
          backend: {
            service: {
              name: "clickhouse-clickhouse", // This needs to match the ClickHouse service name created by the Helm chart
              port: {
                number: 8123, // Default ClickHouse HTTP interface port
              },
            },
          },
        }],
      },
    }],
    // If TLS is required, configure the TLS settings here
  },
}, { dependsOn: clickHouseRelease });

// Optionally, you can output the ingress endpoint for easy access
export const clickhouseIngressEndpoint = clickHouseIngress.status.loadBalancer.ingress[0].hostname;
```

In this program:

- A new Kubernetes namespace is created specifically for ClickHouse.
- The official ClickHouse Helm chart is deployed to the Kubernetes cluster. I've shown how to specify certain values, like enabling persistence and setting the storage size, but this might vary based on the specific Helm chart used for ClickHouse. You should consult the `values.yaml` in the ClickHouse Helm chart for configuration options.
- Traefik is assumed to be already installed and running in your cluster. An Ingress resource is created to route HTTP traffic to the ClickHouse service. Annotations specific to Traefik are added to make sure Traefik handles this Ingress. You should replace the annotations, paths, and service names with those corresponding to your environment.

Keep in mind that the actual code might need adjustments depending on your environment's specifics, the versions of the Helm charts you're using, and how you have set up Traefik.

To apply this Pulumi program:

1. Make sure you have Pulumi installed and configured for TypeScript.
2. Save this code in a file named `index.ts`.
3. Run `pulumi up` from the command line in the directory where the file is saved.

Pulumi will show you a preview of the actions that will be taken based on the code you wrote. If everything looks good, confirm the deployment, and Pulumi will execute the code and create the resources in your Kubernetes cluster.