Deploy the mongo helm chart on Kubernetes

Question

Pulumi · Accepted Answer

To deploy a MongoDB chart on Kubernetes with Pulumi, we'll use the `kubernetes.helm.v3.Chart` resource. Helm is a package manager for Kubernetes that allows you to define, install, and upgrade even the most complex Kubernetes applications. A Helm chart is a collection of files that describe a related set of Kubernetes resources.

The `kubernetes.helm.v3.Chart` resource is a Pulumi abstraction that models a Helm chart. It allows us to deploy packaged applications into a Kubernetes cluster. The chart can be sourced from a remote Helm repository or from a local directory.

Let's step through the necessary code to deploy the MongoDB Helm chart to a Kubernetes cluster. For the purpose of this example, we're assuming that you have already configured your Kubernetes cluster and Pulumi environment correctly.

Here's the TypeScript program to deploy the MongoDB Helm chart:

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

const namespace = new k8s.core.v1.Namespace("mongo-namespace", {
    metadata: { name: "mongo" }
});

const mongoChart = new k8s.helm.v3.Chart("mongo-chart", {
    chart: "mongodb",
    version: "10.22.1", 
    namespace: namespace.metadata.name,
    fetchOpts: {
        repo: "https://charts.bitnami.com/bitnami",
    },
}, { dependsOn: [namespace] });

export const mongoChartName = mongoChart.metadata.apply(md => md.name);
```

In this program, we start by importing the necessary Pulumi libraries. We declare a new Kubernetes namespace for our MongoDB instance, just to keep things organized and separate from other deployments that may exist on the cluster.

We then deploy the MongoDB Helm chart using the `k8s.helm.v3.Chart` constructor. We specify the chart name as `mongodb`, and also provide a version number for the chart which pins the chart to a specific version to ensure our deployment is repeatable.

The `fetchOpts` parameter is used to specify the Helm chart repository URL where the MongoDB chart can be found. In this case, we're using the Bitnami chart repository.

Finally, we declare an export statement. This statement makes the Helm chart's name a stack output, which can be useful if you want to use this information in another context or see it after deployment.

To apply this Pulumi code and deploy the MongoDB Helm chart, you would typically use the Pulumi CLI to perform an update:

```shell
pulumi up
```

After running the command, Pulumi performs a plan and prompts you for confirmation before making any changes. Upon confirmation, it will deploy the MongoDB Helm chart onto your Kubernetes cluster within the specified namespace.