Deploy the elasticsearch-legacy helm chart on Azure Kubernetes Service (AKS)

Question

Pulumi · Accepted Answer

To deploy the `elasticsearch-legacy` Helm chart on Azure Kubernetes Service (AKS), you would first need to provision an AKS cluster, and then you would use Pulumi's Kubernetes provider to deploy the Helm chart onto that cluster.

Below is a detailed explanation followed by a Pulumi program written in TypeScript that demonstrates this process:

1. **Create an AKS Cluster**: To host our application, we first need a Kubernetes cluster. We will create an AKS cluster using the `azure-native:containerservice:KubernetesCluster` resource.

2. **Deploy Helm Chart**: With the cluster in place, we can then deploy the `elasticsearch-legacy` Helm chart. We will use the `kubernetes.helm.v3.Chart` resource from the Pulumi Kubernetes provider for this purpose.

3. **Configure Provider**: The Kubernetes provider needs to be configured with the kubeconfig that we get from the AKS cluster in order to know which cluster to interact with and manage resources on.

Now, let's look at the Pulumi code to accomplish these steps.

```typescript
import * as pulumi from "@pulumi/pulumi";
import * as azure_native from "@pulumi/azure-native";
import * as k8s from "@pulumi/kubernetes";

// Create an Azure Resource Group
const resourceGroup = new azure_native.resources.ResourceGroup("resourceGroup");

// Create an AKS cluster
const cluster = new azure_native.containerservice.KubernetesCluster("aksCluster", {
    resourceGroupName: resourceGroup.name,
    agentPoolProfiles: [{
        count: 1,
        maxPods: 110,
        mode: "System",
        name: "agentpool",
        osType: "Linux",
        vmSize: "Standard_DS2_v2",
    }],
    dnsPrefix: "aks-pulumi",
    // Specify other necessary properties according to your requirements.
    resourceGroupName: resourceGroup.name,
});

// Export the kubeconfig for the cluster
export const kubeconfig = cluster.kubeConfigRaw;

// Create a Kubernetes provider instance that uses our kubeconfig from the AKS cluster
const k8sProvider = new k8s.Provider("k8sProvider", {
    kubeconfig: cluster.kubeConfigRaw,
});

// Deploy the elasticsearch-legacy Helm chart onto the AKS cluster
const elasticsearchChart = new k8s.helm.v3.Chart("elasticsearch-legacy", {
    chart: "elasticsearch-legacy",
    version: "7.10.0",  // Use the version that suits your requirements
    // You can specify the values for the Helm chart as needed.
    // For example:
    // values: {
    //     ...
    // },
}, { provider: k8sProvider });

// Export relevant outputs
export const clusterName = cluster.name;
export const resourceGroupName = resourceGroup.name;
```

In this program:
- We import the required Pulumi packages.
- We begin by creating a new Azure Resource Group using `azure_native.resources.ResourceGroup`.
- We then create an AKS cluster within the resource group by defining an `azure_native.containerservice.KubernetesCluster` resource. Modify the properties as necessary for your scenario (e.g., changing the VM size or the number of nodes).
- Once the cluster is provisioned, its kubeconfig is exported. This sensitive information is what the Kubernetes provider will use to deploy resources to your cluster.
- We create an instance of the Kubernetes provider, `k8s.Provider`, passing the kubeconfig to it. This provider is responsible for deploying the Helm chart onto the AKS cluster.
- We define and create a new Helm chart resource using `k8s.helm.v3.Chart`. The chart name specified should be `elasticsearch-legacy`, and you should adjust the `version` field to the version of the chart that you want to deploy. You can also specify `values` if you need to override any default settings in the Helm chart.
- Finally, we export the AKS cluster name and the resource group name for easy access and reference.

To run this Pulumi program, you would need to have Pulumi installed and configured for use with Azure. You would then execute `pulumi up` within the directory containing this program, and Pulumi will carry out the deployment steps outlined in the code.

Please replace `7.10.0` with the actual version of the `elasticsearch-legacy` Helm chart that you intend to deploy. You can find the available versions by searching the Helm chart repository or using Helm CLI commands.

Keep in mind that this is a basic configuration. Depending on your specific requirements, you might need to set various parameters like the node pool configuration, networking settings, or Helm chart values accordingly.