Deploy the rails helm chart on Digital Ocean Kubernetes Service

Question

Pulumi · Accepted Answer

To deploy a Rails application on Digital Ocean Kubernetes Service using a Helm chart with Pulumi, you will need to follow these general steps:

1. Set up a new Pulumi project and configure it for use with the Digital Ocean provider.
2. Define a Kubernetes cluster resource using the `digitalocean.KubernetesCluster` class.
3. Setup and configure Helm for deploying charts to the Kubernetes cluster.
4. Deploy the Rails Helm chart using the `kubernetes.helm.v3.Chart` resource.

Below is a Pulumi program that demonstrates these steps. This program will create a new Digital Ocean Kubernetes (DOKS) cluster, install the Helm CLI, and then deploy the Rails Helm chart to the cluster.

Before running this TypeScript program, ensure you have installed the Pulumi CLI, set up your Digital Ocean token, and are ready to perform deployments.

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

// Create a Digital Ocean Kubernetes cluster
const cluster = new digitalocean.KubernetesCluster("rails-cluster", {
    region: "nyc3", // Choose the region that works for you
    version: "1.21.5-do.1", // Pick the Kubernetes version
    nodePool: {
        name: "worker-pool",
        size: "s-2vcpu-2gb", // Choose the size that fits your needs
        nodeCount: 2,
    },
});

// Get the Kubeconfig from the created cluster
const kubeConfig = cluster.kubeConfigs[0].rawConfig;

// Create a Kubernetes provider instance that uses our cluster kubeconfig.
const k8sProvider = new kubernetes.Provider("k8s-provider", {
    kubeconfig: kubeConfig,
});

// Deploy the Rails chart using the Helm Chart resource
const railsChart = new kubernetes.helm.v3.Chart("rails-helm-chart", {
    chart: "rails",
    // You may need to specify a repository here if it's not a stable chart
    // For example: repo: "https://charts.bitnami.com/bitnami",
    values: {
        // Here you can specify variables like image, replicas, etc.
        // The content depends on the specific chart and its configurable values.
    },
}, { provider: k8sProvider });

// Export the cluster's kubeconfig and Helm chart deployment status
export const kubeconfig = kubeConfig;
export const deployedChart = railsChart.status;
```

This program initializes a new DOKS cluster in the New York 3 region, with a couple of worker nodes of a basic size, suitable for development or testing. The Kubernetes version is specified; you can change it based on the supported versions available at the time.

Once the cluster is created, we pull out its kubeconfig which will allow us to interact with it using the Kubernetes SDK.

Then, we use the `kubernetes.Provider` with the obtained kubeconfig, which will be used for all the upcoming Kubernetes resource deployments.

Finally, we define a Helm chart resource with `"rails"` as the chart specifier. This assumes that there is a Helm chart named `"rails"` accessible in one of the Helm repositories configured in your environment or a `repo` property can be specified if it is a custom Helm chart.

We use `values` to provide any necessary customizations that the Rails Helm chart accepts. These are typically found in the chart's `values.yaml` file, and can include things like image names, replica counts, resource requests and limits, and any other tunable settings.

The chart deployment status is exported, giving us feedback on whether the deployment was successful.

Please replace the placeholder values provided here with actual values that make sense for your specific scenario. Not every Helm chart will have a default `"rails"` chart, so you may need to determine the correct chart name and repository for your Rails application.

Remember to apply this Pulumi program with the following commands:

```
pulumi up
```

After applying the Pulumi program, check the status of the cluster and Helm release by looking at the exported outputs. You may also use `kubectl` commands to interact with your cluster, using the kubeconfig file that Pulumi outputs.