Deploy the hadoop-yarn helm chart on Opensshift

Question

Pulumi · Accepted Answer

To deploy the Hadoop YARN Helm chart on an OpenShift cluster using Pulumi, we will utilize the `kubernetes.helm.sh/v3.Chart` resource from the Pulumi Kubernetes provider. The Helm chart resource allows us to deploy packaged applications into a Kubernetes cluster.

Helm charts are collections of pre-configured Kubernetes resources that you can deploy as a single unit. YARN (Yet Another Resource Negotiator) is a resource management and job scheduling technology in the Hadoop ecosystem. Deploying a Helm chart for Hadoop YARN consists of installing the chart with the desired settings into your OpenShift cluster.

Before you begin, you need to have:

1. Pulumi CLI installed.
2. `kubectl` installed and configured to connect to your OpenShift cluster.
3. Access to a Helm repository that hosts the Hadoop-YARN chart, if it's not in the default Helm repos.

Here's a Pulumi program in TypeScript that defines a stack for deploying the Hadoop YARN Helm chart to an OpenShift cluster:

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

// This is the name of the Helm chart we want to deploy.
const chartName = "hadoop-yarn";

// Optional: Specify the Helm chart version you want to deploy.
// If not specified, the latest version will be deployed.
const chartVersion = "1.2.3"; // replace with the actual chart version you wish to deploy

// Optional: Specify the Helm repository that contains the Hadoop-YARN chart.
// If the chart is in the default repos, this may not be required.
const helmRepoUrl = "https://example-helm-repo.com";

// Optional: Customize the values.yaml of the Helm chart.
// This is an object where the key-value pairs correspond to the Helm chart values.
const customValues = {
    propertyOne: "valueOne",
    propertyTwo: "valueTwo"
    // Add more customization relevant to the hadoop-yarn Helm chart.
};

// Instantiate a Helm chart resource to deploy Hadoop-YARN.
const hadoopYarnChart = new k8s.helm.v3.Chart(chartName, {
    chart: chartName,
    version: chartVersion,
    fetchOpts: {
        repo: helmRepoUrl
    },
    values: customValues,
    // If required, specify the namespace if it's different from the default.
    // namespace: "your-namespace"
});

// Optional: Export endpoints or other properties for easy access.
export const yarnEndpoint = hadoopYarnChart.getResourceProperty("v1/Service", "hadoop-yarn", "status");

```

### Explanation

- We import the `@pulumi/kubernetes` package to interact with Kubernetes resources.
- We specify some constants for `chartName`, `chartVersion`, `helmRepoUrl`, and `customValues`. This makes our code more maintainable and easier to configure.
  - `chartName` holds the name of the Helm chart we wish to deploy.
  - `chartVersion` is used to pin the chart to a specific version.
  - `helmRepoUrl` is where Pulumi will fetch the Helm chart from. You must replace this with the actual URL of your Helm repo.
  - `customValues` is an object that allows you to override default values in `values.yaml` of the Helm chart, similar to using the `--set` flag with `helm install`.
- We then create a new instance of the Helm chart resource, `hadoopYarnChart`, which will deploy the Hadoop-YARN Helm chart.
- We optionally export a stack output, `yarnEndpoint`, which would allow us to access the endpoint of the deployed YARN service. Note that you may need to customize the `.getResourceProperty` call based on the actual resources and properties you need to extract.

After setting up this Pulumi program, you would run it using the standard Pulumi CLI commands:

```bash
pulumi up
```

Please replace `chartVersion`, `helmRepoUrl`, and any values within `customValues` with the details specific to your chart and desired configuration. If the Hadoop YARN chart requires more specific values (for CPU, memory settings, etc.), they would be set inside the `customValues` object.