Deploy the httpd-template helm chart on Kubernetes

Question

Pulumi · Accepted Answer

To deploy a Helm chart on a Kubernetes cluster using Pulumi, we can use the `kubernetes.helm.v3.Chart` resource from the Kubernetes Pulumi provider. This resource allows you to deploy a Helm chart from a repository or a local path, and configure various parameters as needed.

Here's a step-by-step program that demonstrates how to deploy an `httpd` Helm chart (assuming such a chart exists in the repository you're using) with Pulumi in TypeScript:

1. **Setting up the Pulumi Project**: Create a new Pulumi project and set up the necessary dependencies in your `package.json` file.
2. **Importing Dependencies**: Import the required Pulumi libraries.
3. **Creating the Chart Resource**: Use the `Chart` resource to define the deployment of the Helm chart.
4. **Exporting Outputs**: Optionally, export any outputs such as the status of the deployment.

Make sure you have Pulumi installed and configured with access to your Kubernetes cluster before you run this program.

Let's break down our program:

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

// Create an instance of the Chart class to deploy the httpd-template Helm chart.
const httpdChart = new k8s.helm.v3.Chart("httpd", {
    // Assuming that the httpd-template is available in the default Helm chart repository,
    // otherwise, you may need to specify a `repo` property with the URL of the chart repository.
    chart: "httpd-template",
    // Specify the namespace where the chart should be deployed.
    // If not specified, it will be deployed to the default namespace.
    namespace: "default",
    // Here you can specify custom values for your Helm chart, replacing any default values.
    // The 'values' argument is an object whose properties correspond to different configurable
    // options defined in the chart's 'values.yaml' file.
    values: {
        // For example, set the number of replicas for the httpd deployment.
        // In an actual chart, this would correspond to a real configuration option.
        replicaCount: 1, // This is just a placeholder value; actual configuration might differ.
        // You can also change other configurations such as resource limits, ingress settings, etc.
        // For example:
        // resources: {
        //   limits: {
        //     cpu: "100m",
        //     memory: "128Mi"
        //   },
        //   requests: {
        //     cpu: "100m",
        //     memory: "128Mi"
        //   }
        // }
    },
    // Enable transformation functions if you need to programmatically modify resources before they are applied.
    // For example, to add a common label to all resources deployed by this chart.
    transformations: [
        (resource) => {
            if (resource.metadata) {
                resource.metadata.labels = {...resource.metadata.labels, myLabel: "myValue"};
            }
        },
    ],
});

// Export the status of the helm release.
// The `ready` output indicates if all the resources within the Helm chart are in a ready state.
export const isReady = httpdChart.status.ready;
```

In this TypeScript program:
- We import the `@pulumi/kubernetes` package that includes classes and functions for deploying resources on Kubernetes.
- We create an instance of the `Chart` class to deploy our `httpd` Helm chart. We provide it with:
  - The chart name `httpd-template`. We assume that you have a chart with this name in your chart repository.
  - The namespace to which we want to deploy. Here, we're deploying to the `default` namespace, but you can specify a different one if you wish.
  - Custom values for our chart that allow us to customize its deployment. We only set `replicaCount` for the purposes of this example, but your chart may have different customizable values.
  - An optional transformations array that allows Pulumi to apply changes to the resources before they are applied. We add a label `myLabel` with the value `myValue` to all resources in our example.
- We export an output called `isReady`, which tells us whether all the resources specified in the Helm chart are in a ready state after deployment.

Before running this program, replace placeholder values with actual configurations pertaining to your `httpd-template` chart. Ensure that your Kubernetes cluster is correctly set up and accessible via `kubectl` on the system where you'll be running the Pulumi program.

To run this Pulumi program:
- Install Pulumi and set up the Kubernetes provider following the [Pulumi Kubernetes guide](https://www.pulumi.com/docs/intro/cloud-providers/kubernetes/).
- Create a new Pulumi project with `pulumi new typescript`, which will set up a new TypeScript Pulumi project.
- Add the `@pulumi/kubernetes` package to your `package.json` and install it with `npm install`.
- Replace the contents of `index.ts` with the code above.
- Run `pulumi up` to launch the deployment to your Kubernetes cluster.