Deploy the postgres-instance helm chart on Linode Kubernetes Engine

Question

Pulumi · Accepted Answer

To deploy the `postgres-instance` Helm chart on the Linode Kubernetes Engine (LKE), we'll follow these steps:

1. Set up a new Kubernetes cluster on Linode using Pulumi's `linode` provider.
2. Obtain the kubeconfig file that allows us to interact with the Kubernetes cluster.
3. Use Pulumi's `kubernetes` provider to deploy the `postgres-instance` Helm chart to the cluster.

Here is a Pulumi program in TypeScript that will perform these tasks:

- We will start by creating a new Kubernetes cluster on Linode. This requires the use of the `linode` provider. Note that you must have Linode API credentials configured for Pulumi to perform actions on your behalf.
- Once the cluster is created, we will extract the kubeconfig to interact with the cluster.
- With the kubeconfig, we then proceed to deploy the Helm chart by creating a new `kubernetes.helm.sh/v3.Chart` resource.

The following program assumes you have `@pulumi/linode` and `@pulumi/kubernetes` packages installed.

```typescript
import * as linode from "@pulumi/linode";
import * as k8s from "@pulumi/kubernetes";
import * as pulumi from "@pulumi/pulumi";

// Create a new Linode Kubernetes Engine (LKE) cluster.
const cluster = new linode.LkeCluster("pulumi-lke-cluster", {
    region: "us-central",
    k8sVersion: "1.20",
    label: "pulumi-lke-cluster",
    tags: ["pulumi-cluster"],
    nodePools: [
        {
            count: 2, // Number of nodes
            type: "g6-standard-2", // Node instance type
        },
    ],
});

// Export the kubeconfig to interact with the cluster.
export const kubeconfig = cluster.kubeconfig;

// Create an instance of the Kubernetes provider with the kubeconfig from the LKE cluster.
const k8sProvider = new k8s.Provider("k8s-provider", {
    kubeconfig: cluster.kubeconfig.apply(JSON.stringify),
});

// Deploy the `postgres-instance` Helm chart to the LKE cluster.
const postgresChart = new k8s.helm.v3.Chart("postgres-instance", {
    chart: "postgresql",
    version: "9.1.1", // Use the desired version here
    namespace: "default", // Use the desired namespace here
    fetchOpts: {
        repo: "https://charts.bitnami.com/bitnami",
    },
    // Set desired values for the Postgres Helm chart.
    values: {
        postgresqlUsername: "pulumiuser",
        postgresqlPassword: "pulumi@secret!",
        postgresqlDatabase: "pulumidb",
    },
}, { provider: k8sProvider });

// The following export will give us a direct link to our PostgreSQL service once it's ready.
export const postgresEndpoint = pulumi.interpolate `${cluster.endpoint}:${postgresChart.status.apply(status => status.firstLoadBalancerIngress.port)}`;
```

Explanation:

- `linode.LkeCluster`: This defines a new Kubernetes cluster on Linode using the specified region, Kubernetes version, and node types. It will create a cluster with the label "pulumi-lke-cluster" and a set of tags that include "pulumi-cluster".
  
- `kubeconfig`: The config file that contains the necessary information to connect to the Kubernetes cluster. We are exporting it so it can be used outside the Pulumi program as well, particularly with `kubectl`.
  
- `k8s.Provider`: This resource initializes a new Kubernetes provider instance, which allows us to deploy Kubernetes resources using the kubeconfig from the LKE cluster we created.
  
- `k8s.helm.v3.Chart`: Deploys the Postgres Helm chart from the Bitnami repository to our Kubernetes cluster. We set the chart name to "postgresql", specify the version, and provide the necessary values to configure the Postgres instance, such as username, password, and database name.

- `postgresEndpoint`: We are exporting the endpoint through which the PostgreSQL database can be accessed. This is constructed using the Kubernetes cluster's endpoint and the port to access the Postgres service.

By running this Pulumi program, it will set up a Linode Kubernetes cluster and deploy a PostgreSQL database using the Helm chart. The exported `kubeconfig` and `postgresEndpoint` allow you to interact and connect to your PostgreSQL instance on Linode.