Enabling Debug Mode for Crossplane Controllers

Question

Pulumi · Accepted Answer

When working with Crossplane on Kubernetes, sometimes you might want to enable debug mode to get more detailed logging information, which can be useful for troubleshooting issues with Crossplane controllers. Crossplane controllers are deployed as pods in a Kubernetes cluster, and you can set the `debug` mode by updating the deployment resource for the respective controller.

To achieve this, you would typically edit the deployment YAML directly in Kubernetes either using `kubectl edit` or by applying a new configuration with `kubectl apply`. However, since you are looking to learn how to use Pulumi to manage Kubernetes resources, below I will demonstrate how to update the controller deployment to enable debug mode using Pulumi's TypeScript SDK.

Before we dive in, it's important to have a basic understanding of what Pulumi is: Pulumi is an Infrastructure as Code tool that allows you to declare your infrastructure using familiar programming languages. To get started, you would install the Pulumi CLI, set up your project and stack, and then use code to define the desired state of your infrastructure.

In the following program, I will use the Pulumi Kubernetes provider, which is a package that lets you interact with Kubernetes resources. We will update the `args` property in the deployment specification to include the debug flag for the Crossplane controller.

Here's a step-by-step program that demonstrates this:

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

// Step 1: Create a reference to the namespace where Crossplane is running.
const crossplaneNamespace = new k8s.core.v1.Namespace("crossplane-system", {
    metadata: {
        // You need to provide the name of the namespace where Crossplane is installed.
        name: "crossplane-system",
    },
});

// Step 2: Update the Crossplane controller deployment to enable debug mode.
function enableDebugMode(name: string) {
    return new k8s.apps.v1.Deployment(name, {
        metadata: {
            // The name of the controller deployment, which should be predefined in your cluster.
            name: name,
            namespace: crossplaneNamespace.metadata.name,
        },
    }, {
        // Fetch the existing deployment rather than creating a new one.
        import: name,
        // This transformation will trigger upon deployment creation.
        transformations: [args => {
            // Ensure the args object is a deployment manifest.
            if (args.kind === "Deployment") {
                // Dive into the deployment's spec to modify the containers' args.
                args.spec.template.spec.containers = args.spec.template.spec.containers.map(container => {
                    // Add the debug flag to the arguments of the container.
                    container.args = [...container.args, "--debug"];
                    return container;
                });
            }
        }],
    });
}

// Instantiate the function with the known name of your Crossplane controller deployment.
const controllerDeployment = enableDebugMode("crossplane");

// Export the name of the deployment
export const deploymentName = controllerDeployment.metadata.name;
```

Here's what each part does:

1. We import the Pulumi Kubernetes SDK, which lets us interact with Kubernetes resources in our code.
2. We create a reference to the namespace where Crossplane is running, which will depend on where you have installed Crossplane in your cluster.
3. We define a function `enableDebugMode` that creates a Pulumi Deployment object representing the Crossplane controller. Rather than creating a new deployment, this function changes the Pulumi program's behavior by importing the existing deployment and transforming its manifest to include the `--debug` argument in the container's command-line arguments.
4. We call this function with the name of the Crossplane controller deployment that we want to update. This is an instance where you'll need to know the specific name of the controller deployment in your cluster.
5. Finally, we export the name of the updated deployment so that it can be observed from the Pulumi CLI after the update operation is complete.

By using the `transformations` feature of Pulumi, we've effectively instructed Pulumi to apply a change to the existing deployment without recreating it, which is specifically useful for operations such as enabling debug mode.

Notice that you need to have the Pulumi CLI installed and configured with the appropriate Kubernetes context to use this program. Run the `pulumi up` command to apply the changes to your cluster. If the Crossplane controller deployment exists and is named correctly, Pulumi will update its configuration to enable debug mode logging.