Deploy the zookeeper-3Nodes helm chart on Linode Kubernetes Engine

Question

Pulumi · Accepted Answer

Deploying a Helm chart on a Kubernetes cluster typically involves several steps. First, you must have a Kubernetes cluster up and running. Then you use Helm to manage the deployment of applications, such as the Zookeeper Helm chart. In this case, we'll create a Linode Kubernetes Engine (LKE) cluster and then deploy the Zookeeper Helm chart assuming a Helm chart for Zookeeper is available and named "zookeeper-3Nodes".

For this example, we'll be using Pulumi's TypeScript SDK, which will allow us to define these resources in code and deploy them via the Pulumi CLI. Below I'll provide a detailed explanation and a full program that deploys a three-node Zookeeper cluster on the Linode Kubernetes Engine.

### Explanation:

1. **Linode Kubernetes Engine Cluster**: We will start by creating a Linode Kubernetes Engine cluster using Pulumi's `linode` provider. We will specify the region, number of nodes, and the type of node (Linode instance size).

2. **Helm Chart Deployment**: Once we have the Kubernetes cluster, we will deploy the Zookeeper Helm chart onto the cluster. We use Pulumi's `kubernetes` provider to manage the Helm chart deployment. We'll have to specify the chart name, any custom values we wish to override, and the namespace where we want to deploy our Helm chart.

### Pulumi Program:

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

// Step 1: Create a new Linode Kubernetes Engine cluster
const cluster = new linode.LkeCluster("my-zookeeper-cluster", {
    region: "us-central",
    k8sVersion: "1.21",
    tags: ["pulumi-demo"],
    nodePools: [{
        type: "g6-standard-2",
        count: 3, // This is a 3-node cluster as per your Helm chart "zookeeper-3Nodes"
    }],
});

// Step 2: Deploy the "zookeeper-3Nodes" Helm chart
const zookeeperChart = new k8s.helm.v3.Chart("zookeeper-chart", {
    namespace: "default", // Specify the namespace where the chart will be installed
    chart: "zookeeper-3Nodes", // The name of the chart. Ensure this is available in your Helm repository.
    // You can specify the repository using `repo` attribute if it's not in the default Helm repo.
    values: {
        // Here you can override default values of the Helm chart,
        // for example, if you have custom configuration you wish to apply.
    },
}, { provider: new k8s.Provider("k8s-provider", { kubeconfig: cluster.kubeconfig }) });

// Export the kubeconfig to access the cluster
export const kubeconfig = cluster.kubeconfig;

// Export the public IP to access Zookeeper, if applicable
export const zookeeperEndpoint = zookeeperChart.getResourceProperty("v1/Service", "zookeeper", "status")
    .apply(status => status.loadBalancer.ingress[0].ip);
```

In this program, `my-zookeeper-cluster` is the name of our LKE cluster, and `zookeeper-chart` is the name given to our Helm chart deployment. We export the `kubeconfig` which can be used to interact with the cluster using kubectl or any Kubernetes client.

We also attempt to export the Zookeeper endpoint IP, but please note that this will only work if the Helm chart creates a LoadBalancer service with an external IP. If not, you will need to follow the instructions provided by the chart's maintainers to access your Zookeeper nodes.

Remember that Pulumi's TypeScript programs should be executed with the Pulumi CLI. You would typically follow these steps:
- Run `pulumi up` to preview and deploy your changes.
- After deployment, use `pulumi stack output` to see the output values you've exported.
- You can access kubeconfig using `pulumi stack output kubeconfig` and then use it with kubectl to interact with the cluster.

Make sure to replace dummy values or any placeholders with the actual values for your specific use case. Additionally, ensure that the Helm chart name `zookeeper-3Nodes` is correct. If the chart is hosted in a Helm repository different from the default, you must include the repository URL in the `repo` attribute within the `Chart` resource's arguments.