Using kubernetes pkg.crossplane.io with clickhouse.altinity.com

Question

Pulumi · Accepted Answer

In this program, we will use Pulumi to deploy a Kubernetes cluster and then install a ClickHouse database on it using two different providers: `pkg.crossplane.io` for Kubernetes and `clickhouse.altinity.com` for ClickHouse.

To bring up a Kubernetes cluster, we'll use the Crossplane Kubernetes provider, which allows for the provisioning and management of cloud and on-premises resources in a Kubernetes way. We will configure a `ProviderConfig` resource to communicate with the cloud provider and then deploy a `Cluster` resource to create the actual Kubernetes cluster.

Next, to deploy ClickHouse on the Kubernetes cluster we've provisioned, we will use the ClickHouse operator from Altinity, a ClickHouse technology company. This operator will manage the ClickHouse installation inside our Kubernetes cluster. We'll apply the required custom resource definitions (CRDs) and then deploy a ClickHouse cluster with a `ClickHouseInstallation` resource.

Here's how we'll execute each of these steps in TypeScript using Pulumi:

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

// Step 1: Configure Crossplane provider to manage Kubernetes resources.
// NOTE: We assume that the ProviderConfig is preconfigured in the cluster where Crossplane is installed.

// Define where the provider config is located.
const providerConfig = new crossplane.ProviderConfig('crossplane-provider', {
  metadata: { name: 'default' },
  spec: {
    credentials: {
      source: 'InjectedIdentity',
    },
  },
});

// Step 2: Create a Kubernetes cluster using the known provider.

const cluster = new crossplane.kubernetes.Cluster('cluster', {
  spec: {
    forProvider: {
      // You'll need to configure the following parameters according to your cloud provider.
      // Refer to https://www.pulumi.com/docs/reference/pkg/kubernetes/cluster/ for detailed information.
      // For example on AWS, you might specify `clusterClassRef` and `clusterConfigRef`
      // that include necessary details like VPC configuration, node type, and so on.
    },
  },
  // You'll need to specify the provider configuration that Crossplane will use to create this resource.
  providerConfigRef: {
    name: providerConfig.metadata.name,
  },
});

// Step 3: Deploy ClickHouse operator into the Kubernetes cluster.
// Here we'll use the `ClickHouseInstallation` resource from `clickhouse.altinity.com`
// to deploy the ClickHouse database in the Kubernetes cluster created above.

// First, we need to make sure that our Pulumi program `dependsOn` the cluster being ready.
// We can use `pulumi.interpolation` to ensure that the values we need from the cluster will be
// available when we attempt to use them.

const clickHouseOperator = new kubernetes.yaml.ConfigGroup('clickhouse-operator', {
  files: ['https://raw.githubusercontent.com/Altinity/clickhouse-operator/master/deploy/operator/clickhouse-operator-install.yaml'],
}, { dependsOn: cluster });

// Step 4: Define our ClickHouseInstallation
// Note: Using `kubernetes.yaml.ConfigGroup` here to apply raw YAML, which would contain
//       ClickHouseInstallation kind. In a more practical scenario, you would construct
//       this resource using `kubernetes.apiextensions.CustomResource`.
const clickHouseInstallation = new kubernetes.yaml.ConfigGroup('clickhouse-installation', {
  files: ['clickhouse-installation.yaml'],
}, { dependsOn: clickHouseOperator });

// Export the kubeconfig for the newly created cluster
export const kubeconfig = cluster.status.atProvider.kubeconfig;
```

In the above program:

- We started by setting up the Crossplane provider config which tells Crossplane how to authenticate with the cloud provider's API.
- We created a Kubernetes cluster resource through Crossplane. You must fill in the provider-specific details in the `forProvider` property. For this step, you should refer to the Crossplane's documentation for the specific provider you're using.
- We used the `kubernetes.yaml.ConfigGroup` resource from the Pulumi Kubernetes SDK to apply the ClickHouse operator YAML directly from its GitHub repository. We made sure it depends on the cluster being ready.
- We created another `kubernetes.yaml.ConfigGroup` resource for our ClickHouse installation, pointing to a local `clickhouse-installation.yaml` file which would contain the appropriate CRD definition for a ClickHouse cluster. This also depends on the ClickHouse operator being deployed.

The result is a program that declares our intent to deploy a Kubernetes cluster and then use that cluster to host a ClickHouse database.

Please replace the placeholder comments with the actual configuration according to your cloud provider's requirements and the ClickHouse cluster specifications you desire. You will also need to create a `clickhouse-installation.yaml` file with the definition for the ClickHouse cluster as per the ClickHouse Altinity operator's requirements.