Deploy the topology-discovery helm chart on Rancher

Question

Pulumi · Accepted Answer

To deploy the `topology-discovery` helm chart on Rancher using Pulumi, you first need to ensure that you have Rancher set up and that you have access to a Kubernetes cluster where you want to deploy the chart. Pulumi will interact with Rancher to deploy and manage resources within the cluster.

To accomplish this, we'll use the `rancher2` Pulumi provider, which allows for managing Rancher resources. We will use the `CatalogV2` and `AppV2` resources specifically. The `CatalogV2` resource will add the helm chart repository to Rancher if it's not already available, and the `AppV2` resource will deploy the `topology-discovery` chart to your Kubernetes cluster managed by Rancher.

Here's a step-by-step guide on how to set up the deployment:

1. **Set up Rancher**: You should have Rancher installed and a Kubernetes cluster managed by Rancher.
2. **Prerequisites**: Ensure `kubectl` is configured to communicate with the Kubernetes cluster and Pulumi CLI is installed and configured.
3. **Define the Pulumi program**: We will create a new Pulumi project using TypeScript.
4. **Import the necessary libraries**: We will need `@pulumi/pulumi` and `@pulumi/rancher2`.
5. **Create Resources**: Define your helm chart configuration and deploy it using Pulumi.

First, you should set up a new Pulumi TypeScript project if you haven't already:

```bash
pulumi new typescript
```

Next, in your Pulumi project, create a new TypeScript file (like `index.ts`) and add the following code:

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as rancher2 from "@pulumi/rancher2";

// Cluster information and helm chart details should be modified according to your setup
const clusterId = ""; // Rancher Cluster ID on which you want to deploy your helm chart
const topologyDiscoveryChartName = "topology-discovery"; // Name of the helm chart
const topologyDiscoveryChartVersion = "x.y.z"; // The version of the helm chart
const topologyDiscoveryChartRepoUrl = "http://helm-repository-url/"; // The URL to the helm repository hosting the topology-discovery chart

// Create a new catalog (Helm chart repository) in Rancher
const catalog = new rancher2.CatalogV2("topology-discovery-catalog", {
    clusterId: clusterId,
    url: topologyDiscoveryChartRepoUrl,
    // If additional configuration is needed, you can modify the spec below
});

// Deploy the topology-discovery helm chart
const topologyDiscoveryApp = new rancher2.AppV2("topology-discovery-app", {
    clusterId: clusterId,
    chartName: topologyDiscoveryChartName,
    // The namespace should exist in the cluster, you can use a new or existing one
    namespace: "default", 
    repoName: catalog.metadata.name,
    chartVersion: topologyDiscoveryChartVersion,
    // If you need to specify values for the Helm chart, do it within valuesYaml
    valuesYaml: `
        service:
          type: LoadBalancer
        replicaCount: 2
    `,
    // Refer to the catalog created above
    catalogName: catalog.metadata.name,
});

// To ensure the catalog resource is created before the app
topologyDiscoveryApp.dependsOn = [catalog];

// Export the app URL so we can access it after deployment
export const appUrl = topologyDiscoveryApp.status.url;
```

This code snippet does the following:

- Imports the Pulumi SDK and the Rancher2 provider which we'll use to interact with your Rancher-managed Kubernetes cluster.
- Defines the `CatalogV2` resource, which must reference a `clusterId` variable that corresponds to your Rancher Kubernetes cluster, and the URL to a helm chart repository that holds the `topology-discovery` helm chart.
- Defines the `AppV2` resource to install the helm chart. It uses the `chartName`, `chartVersion`, and `clusterId` to specify which chart to install on which cluster. The `namespace` parameter specifies where the chart should be deployed within the cluster (which must already exist), while `repoName` links to the repository we created previously.
- The `valuesYaml` string allows you to specify any custom values to override the default helm values, in this case, what type of Service to expose and the number of replicas.
- We also mark the chart repository as a dependency for the helm chart installation to ensure the repository is added before the helm chart is deployed.
- The `appUrl` is then exported which Pulumi provides as an output once the app is deployed and if it has a reachable URL.

After setting up your `index.ts`, run `pulumi up` from the command line to preview and deploy your stack.

Keep in mind, that this is a generalized example and some values will depend on your specific infrastructure and the `topology-discovery` helm chart.

You would need to install the Rancher2 provider if you haven't already:

```bash
npm install @pulumi/rancher2
```

Once the process is complete, the `appUrl` will give you a way to access the service exposed by the helm chart.

This is a basic Pulumi program to deploy a helm chart to a Rancher managed cluster. For any specific configuration related to the `topology-discovery` helm chart, you will have to refer to the chart's values file and replicate the settings you require as `valuesYaml`.