Using kubernetes networking.istio.io with networking.cfargotunnel.com

Question

Pulumi · Accepted Answer

To use Kubernetes with Istio for service mesh capabilities and integrate it with Cloudflare's Argo Tunnel for secure and fast networking, you will follow multiple steps to configure these services. Istio is an open-source service mesh that provides a way to control how microservices share data with one another. Meanwhile, Cloudflare Argo Tunnel creates a secure, outbound-only, connection between your Kubernetes cluster and Cloudflare's network which helps in protecting your cluster from direct internet access.

Here's a high-level overview of the steps before diving into the code:

1. Set up your Kubernetes cluster.
2. Install Istio into the Kubernetes cluster.
3. Configure Istio as needed, possibly including an Ingress Gateway for managing inbound traffic.
4. Set up Cloudflare Argo Tunnel, ensuring your domain is configured with Cloudflare.
5. Deploy a Kubernetes Service and a corresponding Istio Gateway and Virtual Service to manage and route traffic through the Argo Tunnel.

Pulumi doesn't directly manage your domain DNS on Cloudflare or install software like Istio, as these tasks are generally done outside of a Pulumi program. Pulumi is used to declare cloud infrastructure but the setting up of certain software components might need specific CLI commands or other installation processes.

However, Pulumi can be used to define a Kubernetes Service, Istio Gateway, and Virtual Service. You will need to install Istio separately, configure your Cloudflare DNS and Argo Tunnel, and then use Pulumi to deploy the Kubernetes resources.

Given the information, I'm going to share a TypeScript program that assumes:

- You have a Kubernetes cluster configured and have the `kubeconfig` file on your local machine.
- Istio is already installed on your Kubernetes cluster.
- You have set up Cloudflare Argo Tunnel according to their documentation and have the necessary configuration files.

Below I'll share a program that defines:

- A Kubernetes service to expose a sample application.
- An Istio Gateway resource to manage entry points into the service mesh.
- A Virtual Service for Istio that routes traffic to the Kubernetes service.

Please replace placeholders with actual values from your setup where appropriate.

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

// Create a Kubernetes Service to expose the application
const appService = new k8s.core.v1.Service("app-service", {
  metadata: {
    name: "my-service", // Name of your service
    labels: {
      app: "my-app", // Should match with the selector below
    },
  },
  spec: {
    type: "ClusterIP",
    selector: {
      app: "my-app", // Selector to match the correct pods
    },
    ports: [
      {
        protocol: "TCP",
        port: 80,
        targetPort: 8080,
      },
    ],
  },
});

// Create an Istio Gateway to manage ingress traffic
const gateway = new k8s.networking.v1beta1.Ingress("istio-gateway", {
  metadata: {
    name: "my-gateway", // Name of your gateway
    annotations: {
      // Custom annotations for Cloudflare Argo Tunnel can go here
    },
  },
  spec: {
    selector: {
      istio: "ingressgateway", // Assuming default Istio labels, verify with your Istio installation
    },
    servers: [
      {
        port: {
          number: 80,
          name: "http",
          protocol: "HTTP",
        },
        hosts: ["*"], // Specify your host or leave as wildcard
      },
    ],
  },
});

// Create a Virtual Service to define traffic routing rules
const virtualService = new k8s.networking.v1alpha3.VirtualService("virtual-service", {
  metadata: {
    name: "my-virtual-service", // Name of the virtual service
  },
  spec: {
    hosts: [
      // Hostnames to which the VirtualService applies
      // You'll replace this with the hostname you've configured in Cloudflare's DNS
      "example.com",
    ],
    gateways: [
      "my-gateway", // The name of your Istio Gateway
    ],
    http: [
      {
        match: [
          {
            uri: {
              prefix: "/", // This matches all paths, you can customize this as needed
            },
          },
        ],
        route: [
          {
            destination: {
              host: "my-service", // Points to the Kubernetes Service defined earlier
              port: {
                number: 80,
              },
            },
          },
        ],
      },
    ],
  },
});

// After running `pulumi up`, you can export the service URL for ease of access.
export const serviceUrl = appService.metadata.apply(m => `http://${m.name}.${m.namespace}.svc.cluster.local`);

```

This Pulumi program defines the basic Kubernetes and Istio resources for a service exposed via Cloudflare Argo Tunnel. After deployment, all traffic to `example.com` will be routed through the Istio Gateway and to the `my-service` Kubernetes Service, subject to any Istio Policies you've defined.

Please note that you will have to follow Istio's documentation to install it on your cluster and manage its configuration. Similarly, the actual management of the Cloudflare Argo Tunnel, such as setting up the `cloudflared` daemon and configuring DNS records, will need to be performed according to Cloudflare's documentation and using respective CLI tools or Cloudflare's admin panel.