Deploy the variant-cron helm chart on Azure Kubernetes Service (AKS)

Question

Pulumi · Accepted Answer

To deploy the `variant-cron` Helm chart on Azure Kubernetes Service (AKS), we’ll follow these steps:

1. **Set up AKS Cluster**: First, we need to provision an AKS cluster where our Helm chart will be deployed.

2. **Install Helm Chart**: After the cluster is set up, we will use Pulumi’s Helm v3 support to deploy the `variant-cron` Helm chart onto the AKS cluster.

For the Helm Chart deployment, I'll assume that `variant-cron` is available in one of the Helm repositories. If it's a custom chart or located in a private repository, you would need to adjust the `repo` attribute to point to that repository or configure the repository access accordingly.

Below is a Pulumi program written in TypeScript to perform these actions.

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as azure from "@pulumi/azure";
import * as kubernetes from "@pulumi/kubernetes";
import * as azuread from "@pulumi/azuread";
import * as tls from "@pulumi/tls";

// Step 1: Set up an AKS Cluster
// We'll create a new resource group, an AD service principal, and finally an AKS cluster.

// Create an Azure Resource Group
const resourceGroup = new azure.core.ResourceGroup("resourceGroup", {
    location: "East US", // You can change this to the location of your choice
});

// Create an AD service principal for the AKS cluster.
const adApp = new azuread.Application("aks", {});
const adSp = new azuread.ServicePrincipal("aksSp", { applicationId: adApp.applicationId });

// Generate random password.
const password = new tls.PrivateKey("password", {
    algorithm: "RSA",
});

// Create the Service Principal Password
const adSpPassword = new azuread.ServicePrincipalPassword("aksSpPassword", {
    servicePrincipalId: adSp.id,
    value: password.privateKeyPem,
    endDate: "2099-01-01T00:00:00Z",
});

// Create the AKS cluster
const aksCluster = new azure.containerService.KubernetesCluster("aksCluster", {
    resourceGroupName: resourceGroup.name,
    linuxProfile: {
        adminUsername: "adminuser",
        sshKey: {
            keyData: password.publicKeyOpenssh,
        },
    },
    servicePrincipal: {
        clientId: adApp.applicationId,
        clientSecret: adSpPassword.value,
    },
    defaultNodePool: {
        name: "aksagentpool",
        nodeCount: 1,
        vmSize: "Standard_DS2_v2",
    },
    dnsPrefix: `${pulumi.getStack()}-kube`,
});

// Export the KubeConfig
export const kubeConfig = aksCluster.kubeConfigRaw;

// Step 2: Install Helm Chart
// We will declare the Helm chart using Pulumi’s Helm Chart resource.

// Create a Kubernetes provider instance that uses our cluster from above.
const k8sProvider = new kubernetes.Provider("k8sProvider", {
    kubeconfig: kubeConfig,
});

// Deploy the variant-cron Helm chart into the AKS cluster
const variantCronChart = new kubernetes.helm.v3.Chart("variant-cron-chart", {
    chart: "variant-cron",
    // You must specify the repository where your chart is hosted. If the chart is in a well-known repository
    // like "stable" or "bitnami", you don't need to specify the `repo` attribute.
    // repo: "http://myhelmrepo.org",
    values: {
        // Specify your Helm values here.
    },
}, { provider: k8sProvider });

// Optionally, you can export the status of the deployed Helm release
export const helmChartStatus = variantCronChart.status;
```

Before running this Pulumi program, you must have Pulumi installed and configured for use with Azure. Please follow Pulumi’s Azure [setup documentation](https://www.pulumi.com/docs/get-started/azure/) to do so.

**What this program does**:

1. **Resource Group Creation**: We start by creating a new Azure Resource Group, which is a container that holds related resources for an Azure solution.

2. **Azure AD Application and Service Principal**: This is required by AKS to interact with Azure APIs. We create new Azure Active Directory (AD) applications and service principals for the AKS cluster.

3. **SSH Key Generation**: We are using the `tls` package to generate a new RSA key pair. This is because AKS requires an SSH key pair to access the nodes in your Kubernetes cluster.

4. **AKS Cluster Creation**: With the service principal and SSH public key, we create the Kubernetes cluster using the `azure.containerService.KubernetesCluster` class.

5. **Export KubeConfig**: The `kubeConfig` is outputted for use with `kubectl` and other Kubernetes tools.

6. **Helm Chart Deployment**: We create a Kubernetes provider that's wired to the credentials for our new AKS cluster, and then we declare our variant-cron Helm chart, specifying the chart name and any values that are needed for customizing the installation.

After running `pulumi up`, Pulumi will provision these resources in the order specified, taking care of dependencies between resources automatically.

To access the Kubernetes cluster, you can use the exported `kubeConfig` or the [Azure CLI](https://docs.microsoft.com/en-us/cli/azure/aks?view=azure-cli-latest) (`az aks get-credentials`). Once you have your cluster set up, you can use `kubectl` to interact with your AKS cluster, deploy applications, and manage workloads.