Deploy the deploy-flask helm chart on Opensshift

Question

Pulumi · Accepted Answer

Deploying a Flask application using Helm on OpenShift involves several steps. We'll use Pulumi to set up our deployment using the Helm Chart resource from the @pulumi/kubernetes package. Helm simplifies the process of defining, installing, and upgrading applications on Kubernetes by using pre-defined templates called "charts".

The following Pulumi program uses the Chart resource from the @pulumi/kubernetes package to deploy a Flask application using a Helm chart.

Firstly, ensure you've got the Pulumi CLI installed, as well as kubectl configured to connect to your OpenShift cluster. OpenShift has its own CLI tool, oc, but kubectl is compatible with OpenShift as well. Make sure that Helm is configured correctly and that you have access to the chart you wish to deploy.

Here's the Pulumi TypeScript program that defines the deployment:

import * as k8s from "@pulumi/kubernetes";

// The name you want to give to your Helm chart deployment.
const chartName = "flask";

// Namespace where you want to deploy your chart.
const namespace = "default"; // Change this to the namespace you intend to use in OpenShift

const flaskChart = new k8s.helm.v3.Chart(chartName, {
    // Assuming 'deploy-flask' is the name of your Helm chart
    chart: "deploy-flask",
    // Replace with the repository where your Helm chart is located, if it's not in a default repo.
    // repo: "https://my-helm-chart-repo/",
    version: "1.0.0", // Specify the version of the chart you want to deploy
    namespace: namespace,
    values: {
        // Custom values to pass to the Helm chart. For example:
        // service: {
        //   type: "LoadBalancer"
        // }
        // Add your own custom values based on the 'deploy-flask' chart's `values.yaml` file.
    },
}, { provider: new k8s.Provider("k8s-provider", { kubeconfig: "<YOUR_KUBECONFIG_CONTENTS>" }) });

// Export the Chart's status to enable easy access to the Chart's resources after deployment.
export const status = flaskChart.status;

This is a basic example, and you may need to customize the values section with the actual variables and values used by your Helm chart for Flask.

Let's go through the various parts of the code:

We import the Kubernetes module from Pulumi.
We create a Chart resource, which is how Pulumi understands and interacts with Helm charts.
The chart property specifies the name of the Helm chart we want to deploy.
The version property specifies the version of the chart to use.
The namespace property specifies the Kubernetes namespace to deploy the chart into.
The values property holds configurations specific to the Flask chart you have. These values override the defaults in the chart's values.yaml file.
We also define a Kubernetes provider with kubeconfig, which helps Pulumi communicate with your Kubernetes cluster. You need to replace "<YOUR_KUBECONFIG_CONTENTS>" with the actual contents of your kubeconfig file or use other means to authenticate, such as the default provider which assumes kubeconfig is set in your environment.

Keep in mind that to access your OpenShift cluster, you need to have the proper permissions configured and be able to connect to it through kubectl or oc.

After writing the code above into a .ts file, you can deploy it with Pulumi CLI commands:

pulumi up to preview and deploy the changes.
Confirm the preview looks correct and select yes to proceed with the deployment.

Once the Pulumi process completes, you will have your Flask application running on OpenShift, packaged and managed by Helm. If you need to make changes to the configuration, you can modify the values passed to the Chart resource and run pulumi up again to apply the changes.