Deploy the aws-rds-postgresql-database helm chart on Kubernetes

Question

Pulumi · Accepted Answer

Deploying an AWS RDS PostgreSQL database using a Helm chart on a Kubernetes cluster involves a series of steps. We will be leveraging Pulumi's Kubernetes provider to orchestrate the needed resources. Pulumi's model allows us to define our infrastructure in code, which can be versioned, shared, and reused.

Here's an overview of the process:
1. **Prerequisites**: Ensure you have a Kubernetes cluster running and that Pulumi is configured with access to the cluster.
2. **Initialize a Pulumi Project**: The project houses our infrastructure code.
3. **Write the Infrastructure Code**: Write the code to deploy the Helm chart for PostgreSQL.
4. **Deploy the Infrastructure**: Use the Pulumi CLI to deploy the Helm chart to the Kubernetes cluster.
5. **Verify the Deployment**: Check that the PostgreSQL database has been created and is running as expected.

Below is a Pulumi program written in TypeScript that deploys a PostgreSQL Helm chart to a Kubernetes cluster:

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

// Step 1: Initialize the Helm chart repository.
const postgresqlRepo = 'https://charts.bitnami.com/bitnami';
const repoName = 'bitnami';

const postgresqlChart = new kubernetes.helm.v3.Chart('postgresql', {
    repo: repoName, // Name of the repository.
    chart: 'postgresql', // Name of the chart.
    version: '10.3.11', // Version of the chart.
    fetchOpts: { repo: postgresqlRepo }, // Fetch options to add the repo.
    // You can specify PostgreSQL configuration here.
    values: {
        global: {
            storageClass: 'standard', // Specify the storage class for database storage.
        },
        image: {
            registry: 'docker.io',
            repository: 'bitnami/postgresql',
            tag: '11.11.0' // Use a specific Postgres image version.
        },
        // Define credentials for the database.
        postgresqlUsername: 'admin', // Default username for PostgreSQL.
        postgresqlPassword: 'password', // Default password for PostgreSQL.
        postgresqlDatabase: 'my_database', // Default database name.
        service: {
            type: 'ClusterIP', // Expose PostgreSQL inside the cluster.
        },
        persistence: {
            enabled: true, // Enable data persistence through PVC.
            storageClass: 'gp2', // Specify AWS storage class for persistence.
            size: '10Gi', // Size of the persistent volume.
        }
    }
}, { provider: new kubernetes.Provider('k8s-provider') });

// Export the PostgreSQL service name and cluster IP for easy access.
export const postgresqlServiceName = postgresqlChart.getResourceProperty("v1/Service", "postgresql", "metadata").apply(m => m.name);
export const postgresqlClusterIP = postgresqlChart.getResourceProperty("v1/Service", "postgresql", "spec").apply(s => s.clusterIP);

```

This Pulumi program performs the following actions:

1. It imports the necessary Kubernetes package from Pulumi, which is a requirement to interact with your Kubernetes cluster.
2. The Helm chart for PostgreSQL is initialized using the `Chart` class. The chart is pulled from the specified repository (`https://charts.bitnami.com/bitnami`), which is known for providing well-configured and maintained Helm charts.
3. The `values` field allows us to customize the Helm chart according to our needs, such as specifying image/version, credentials, service type, and persistent volume configurations.
4. After running the program, Pulumi will create a PostgreSQL Helm deployment in your Kubernetes cluster with all the specified configurations.
5. We have also added two export statements to output the service name and cluster IP, which can be used to interact with the PostgreSQL database.

To deploy this PostgreSQL database, you'll need to run the following commands after installing Pulumi CLI and configuring AWS and kubectl:

1. Create a new Pulumi project if you haven't already:

```bash
    pulumi new typescript
    ```

2. Replace the contents of `index.ts` with the code above.
3. Deploy it using:

```bash
    pulumi up
    ```

After the deployment, Pulumi will print out the `postgresqlServiceName` and `postgresqlClusterIP` as part of the stack's outputs. You can use these details to connect to the PostgreSQL instance within your Kubernetes cluster.

Be sure to manage the credentials securely and follow best practices for production use, like using randomly generated passwords and handling them as secrets. The values provided in the `values` field are example defaults and should be changed to more secure values before use in a production environment.