Using kubernetes install.istio.io with helm.fluxcd.io

Question

Pulumi · Accepted Answer

To accomplish the installation of Istio on a Kubernetes cluster using Helm and integrating with FluxCD for GitOps, you'll write a Pulumi program in TypeScript. Istio is a service mesh that helps manage complex deployments on Kubernetes. FluxCD is a tool that automates the deployment of apps to Kubernetes using a GitOps approach.

Here’s the high-level approach to what we’re going to achieve with the Pulumi program:

Define a Kubernetes resource for a Helm Release: This will instruct Kubernetes to install Istio via its Helm chart.
Integrate with FluxCD: The Helm Release will be managed by FluxCD, which will synchronize the state of the Istio deployment with a defined state in a Git repository.

I'll provide you with a step-by-step explanation in the code comments. The assumption here is that you already have a Kubernetes cluster configured and have both Helm and FluxCD setup tools available in your environment. If not, these should be installed and set up prior to running the program.

Let's write the Pulumi program to deploy Istio using Helm and manage it through FluxCD.

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

// Define the settings of the Istio Helm chart.
const istioHelmReleaseSettings = {
    // Repository settings for the Helm chart.
    chart: "istio",
    version: "1.11.4", // Specify the version of Istio you want to install.
    fetchOpts: {
        repo: "https://istio-release.storage.googleapis.com/charts",
    },
};

// Create a Helm Release for Istio, this will instruct the Kubernetes cluster
// to install Istio using the Helm chart with the settings defined above.
const istioRelease = new kubernetes.helm.v3.Release("istio-release", {
    chart: istioHelmReleaseSettings.chart,
    version: istioHelmReleaseSettings.version,
    namespace: "istio-system", // It’s recommended to install Istio in its own namespace.
    values: {
        // Define any custom values for the Helm chart here.
        global: {
            // Your custom values go here.
        },
    },
    repositoryOpts: istioHelmReleaseSettings.fetchOpts,
}, { provider: new kubernetes.Provider("k8s-provider", { kubeconfig: "<your-kubeconfig>" }) });

// To integrate with FluxCD, define a GitRepository and a HelmRepository CRD
// FluxCD will monitor changes in these resources to synchronize your cluster state.

// Define a GitRepository resource which points to your configuration repository
const gitRepo = new kubernetes.apiextensions.CustomResource("flux-git-repo", {
    apiVersion: "source.toolkit.fluxcd.io/v1beta1",
    kind: "GitRepository",
    metadata: {
        name: "my-istio-config",
        namespace: "flux-system"
    },
    spec: {
        interval: "1m", // How often to check for changes
        url: "<your-git-repo-url>", // URL to your Git repository
        ref: {
            branch: "main", // Git branch to sync from
        },
    }
}, { provider: new kubernetes.Provider("k8s-provider") });

// Export the name of the Istio release
export const istioReleaseName = istioRelease.status.name;

Make sure to replace "<your-kubeconfig>" with the path to your Kubernetes config file and "<your-git-repo-url>" with the URL to your Git repository where your Kubernetes and Istio configuration lives.

In the Pulumi program, we establish a new Helm release with the name istio-release to install Istio on a Kubernetes cluster. We specify the particular Istio Helm chart version we want to deploy and any necessary configuration values. The namespace option is set to istio-system, which is the recommended namespace for installing Istio.

Following the Istio release, we define a custom resource for a GitRepository, which FluxCD will monitor. FluxCD will pull the configuration from this Git repository and ensure the actual state of Istio on the cluster matches the desired state defined in the repository. We set it to check for new commits every minute.

To apply this Pulumi program, save the code as index.ts in a new Pulumi project directory. Then, run pulumi up which will prompt you to create a new stack and execute the deployment, installing Istio on your cluster and setting up FluxCD for continuous delivery.

Please note, for a real-world scenario, you'll need to ensure that your cluster has FluxCD installed and that the CustomResourceDefinitions (CRDs) for GitRepository and other Flux-related resources are applied to your cluster. The program assumes that these CRDs are already existing and your Pulumi setup has the necessary credentials to interact with the Kubernetes API.