Deploy the postgres-cluster helm chart on Kubernetes

Question

Pulumi · Accepted Answer

To deploy a PostgreSQL cluster on Kubernetes using a Helm chart with Pulumi, you'll need to follow these steps:

1. Ensure you have Pulumi installed and configured for use with your Kubernetes cluster. You should have `kubectl` configured to communicate with your Kubernetes cluster as well.

2. Create a new directory for your Pulumi project if you haven't already and change to that directory.

3. If you haven't yet, initialize the Pulumi project by choosing a template that suits your language preference, in this case, TypeScript.

4. Create a TypeScript program within your Pulumi project that utilizes the `@pulumi/kubernetes` package to deploy a Helm chart.

The `kubernetes.helm.v3.Chart` resource from the `@pulumi/kubernetes` package is used to deploy a Helm chart in Kubernetes using Pulumi. This resource is an abstraction that allows you to deploy Helm charts into your Kubernetes clusters—in this case, the PostgreSQL Helm chart.

Here’s a Pulumi TypeScript program that deploys the PostgreSQL Helm chart to your configured Kubernetes cluster:

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

// Create a new PostgreSQL chart instance.
// This assumes you have access to the chart in a reachable Helm chart repository.
const postgresCluster = new kubernetes.helm.v3.Chart("postgres-cluster", {
    chart: "postgresql",
    version: "10.3.11", // Specify the version of the chart to deploy
    fetchOpts: {
        repo: "https://charts.bitnami.com/bitnami", // PostgreSQL chart repository
    },
    
    // This is where you can provide custom values to the chart.
    // The `values` field enables you to specify configuration for the chart.
    values: {
        // Set typical values like replica count, image version, or any value supported by the chart.
        postgresqlUsername: "my-pg-user",
        postgresqlPassword: "my-pg-password",
        postgresqlDatabase: "my-database",
        replicaCount: 3
    },
});

// Export the necessary information of the PostgreSQL deployment (if needed)
export const postgresClusterName = postgresCluster.metadata.name;
export const deployedResources = postgresCluster.resources;
```

This code will deploy a PostgreSQL chart. Here's a breakdown of what each part of the code does:

- Imports the Kubernetes package from Pulumi's SDK.
- Utilizes the `kubernetes.helm.v3.Chart` class to deploy a PostgreSQL Helm chart from Bitnami's Helm repository.
- Specifies the chart name, `postgresql`, and its version.
- Overrides default settings using the `values` object, setting the PostgreSQL username, password, database name, and replica count. These values would be specific to your requirements and would typically be externalized in real-world scenarios.
- Exports outputs like the dynamic name assigned to PostgreSQL chart deployment and a list of deployed Kubernetes resources, which can be used for further inspection or dependencies in Pulumi.

After drafting your Pulumi program, you run the program with the Pulumi CLI, which performs the deployment to your Kubernetes cluster.

Please note, the values provided to the PostgreSQL chart through `values:` should be carefully managed, as they may contain sensitive information like database passwords. In production environments, such information should be managed through secrets and not hard-coded in plaintext in your Pulumi programs.