Using kubernetes ingress with stackgres.io

Question

Pulumi · Accepted Answer

When working with Kubernetes, Ingress is an API object that manages external access to the services in a cluster, typically HTTP. StackGres is a full-stack PostgreSQL distribution for Kubernetes, packaged as an Operator. Using an Ingress in conjunction with StackGres allows you to expose PostgreSQL services running within your Kubernetes cluster to the outside world in a controlled and secure manner.

Below is a basic program in TypeScript that demonstrates how you might set up an Ingress resource to work with a PostgreSQL database managed by StackGres. For the purposes of this example, we'll assume that you have already installed the StackGres Operator on your cluster and have a PostgreSQL service that you want to expose.

First, we'll use `kubernetes.networking.k8s.io/v1.Ingress`, which is part of the Kubernetes Pulumi package. An Ingress requires an IngressClass, and this needs to support the controller we are using. For simplicity, we are assuming a default IngressClass is available on the cluster.

Here’s how you can create an Ingress resource using Pulumi with TypeScript:

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

const name = "stackgres-ingress";

// Define the Ingress resource.
const postgresIngress = new k8s.networking.v1.Ingress(name, {
    // Add necessary metadata here, like labels and annotations.
    metadata: {
        name: name,
        labels: { app: "stackgres" },
        // Annotations may include configuration for your ingress controller.
        // This could be Nginx, Traefik, etc., depending on what is available on your cluster.
        annotations: { 
            "kubernetes.io/ingress.class": "nginx",
            // Additional annotations for SSL, configuration snippets, etc. go here.
        },
    },
    // The spec defines how to route traffic to the service.
    spec: {
        // The rules to forward traffic.
        rules: [{
            // Assuming you use a domain like 'postgres.mycompany.com' association.
            host: "postgres.mycompany.com", 
            http: {
                paths: [{
                    path: "/",                  // Route all traffic from the root path.
                    pathType: "ImplementationSpecific",
                    backend: {
                        service: {
                            name: "stackgres-db-service", // Name of your StackGres PostgreSQL service.
                            port: {
                                number: 5432,     // Default PostgreSQL port.
                            },
                        },
                    },
                }],
            },
        }],
        // If you're using TLS, define your TLS settings here.
        tls: [{ 
            hosts: ["postgres.mycompany.com"],
            // Define the Kubernetes Secret that contains the TLS certificate information.
            secretName: "postgres-tls-secret" 
        }],
    },
});

// Export the ingress's name and IP address for easy access.
export const ingressName = postgresIngress.metadata.name;
export const ingressIp = postgresIngress.status.loadBalancer.ingress[0].ip;
```

In the program above:

- We import the `@pulumi/kubernetes` package to interact with Kubernetes resources.
- We create a new `Ingress` object using `new k8s.networking.v1.Ingress`.
- The `metadata` section includes the name of the resource, any labels we want to attach for organizational purposes, and annotations to configure the ingress controller.
- The `spec` section defines how the traffic should be routed. Under `rules`, we configure the Ingress to route traffic to our StackGres service.
- We assume the Postgres service is exposed on port 5432 and is named `stackgres-db-service`.
- If you've configured TLS/SSL, you'll need to specify the details in the `tls` section.

You would adapt this code to match the particulars of your setup, such as your domain, the name of your service, and certificate details.

Remember that before running the Pulumi program, you would need to have Pulumi installed and configured to use your Kubernetes cluster. Also, these resources would be created in the default namespace unless a specific namespace is specified. If needed, you can set the appropriate namespace in the metadata field.

If you plan to create Ingress resources often or manage a complex system with Pulumi, considering modularizing your code could be beneficial. Modularity allows you to reuse code and create more manageable and maintainable codebases.