Deploy the harperdb helm chart on Linode Kubernetes Engine

Question

Pulumi · Accepted Answer

To deploy the HarperDB Helm chart on Linode Kubernetes Engine (LKE), you'll need to complete several steps. First, you must provision an LKE cluster; then you must configure your Kubernetes environment to interact with the cluster, and finally, you’ll deploy the HarperDB Helm chart to the cluster.

The following Pulumi program is written in TypeScript. It includes two major steps:

1. Provisioning an LKE cluster
2. Deploying the HarperDB Helm chart to that cluster

For this example, I'll use Pulumi's Kubernetes provider to interact with the Kubernetes API and deploy the Helm chart to the LKE cluster. Note that you'll need to have the Linode CLI configured with appropriate API tokens and access to manage resources on Linode.

Before running this Pulumi program, you should have the following prerequisites in place:
- Pulumi CLI installed and set up
- Linode CLI configured with your API token
- Helm CLI installed locally (optional, for Helm charts)
- Pulumi Kubernetes provider installed

Here's a Pulumi program that does this:

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

// Step 1: Provision an LKE cluster on Linode.
const cluster = new linode.LkeCluster("my-lke-cluster", {
    label: "my-lke-cluster",
    k8sVersion: "1.20", // specify the desired Kubernetes version
    region: "us-central", // specify the Linode region
    pool: [{
        type: "g6-standard-2", // specify the node type
        count: 3, // specify the number of nodes
    }],
});

// Export the Kubeconfig to interact with your cluster using `kubectl`
export const kubeconfig = cluster.kubeconfig;

// Step 2: Deploy the HarperDB Helm chart to the LKE cluster.
// set up the provider to use the kubeconfig from the newly created LKE cluster
const provider = new k8s.Provider("lke-k8s-provider", {
    kubeconfig: cluster.kubeconfig.apply(JSON.stringify),
});

// Deploy the HarperDB Helm chart
const harperdbChart = new k8s.helm.v3.Chart("harperdb-helm-chart", {
    chart: "harperdb",
    version: "1.0.0", // Specify the chart version; ensure it's compatible
    fetchOpts: {
        repo: "https://helm-repository-url/", // Specify the Helm repository URL containing the HarperDB chart
    },
    // You can include additional configuration parameters here
}, { provider }); // ensure you pass the provider that relates to your LKE cluster

// Export the HarperDB service endpoint
export const harperDbEndpoint = harperdbChart.getResourceProperty("v1/Service", "harperdb-helm-chart-harperdb", "status").apply(status => status.loadBalancer.ingress[0].ip);
```

### Explanation

1. We begin by importing the required Pulumi packages:
   - `@pulumi/kubernetes` to work with Kubernetes resources
   - `@pulumi/linode` to manage Linode resources including the LKE cluster
   - `@pulumi/pulumi` to interact with the Pulumi runtime environment and state

2. We create an LKE (Linode Kubernetes Engine) cluster using `linode.LkeCluster`. This resource takes several arguments, including cluster label, desired Kubernetes version, region for deployment, and a pool specification that includes the type and count of nodes.

3. We export the `kubeconfig` parameter from our LKE cluster to enable interaction with the cluster through `kubectl`. The `kubeconfig` contains necessary information to connect to the cluster and control it via the Kubernetes API.

4. After creating the LKE cluster, we define a Kubernetes provider (`k8s.Provider`) that uses the generated `kubeconfig` of our cluster. This provider will be used to interact with the Kubernetes cluster and deploy resources onto it.

5. We deploy the HarperDB Helm chart using `k8s.helm.v3.Chart`. The Chart resource takes several arguments:
   - `chart`: name of the Helm chart
   - `version`: the chart version
   - `fetchOpts`: additional chart fetch options like the Helm repository URL
   
   We also pass the LKE Kubernetes provider created above to this resource so that it knows which Kubernetes cluster to deploy the chart on.

6. Lastly, we export `harperDbEndpoint`, which is a way to obtain the Service IP of the deployed HarperDB once it's up and running. This will give us an endpoint that we can use to interact with the HarperDB database.

To execute this Pulumi program, run `pulumi up` from the command line in the directory where this code is saved. Ensure you have selected the correct stack which connects to the Linode environment where you want your resources to be provisioned.