README.md

Templating Kubernetes resources with .NET Core

In this section you will learn how to use Javascript to:

• create JSON (and YAML) definition for a Kubernetes Pod
• submit a Pod definition to the cluster with code

Let's get started.

Prerequisites

Ensure that you have installed .NET Core 3.1. See documentation for installation instructions.

Generating Pod definitions

You can generate yaml by navigating to genyaml project and running it.

cd genyaml
dotnet build
dotnet run

The output is a JSON object for the Pod.

{
  "apiVersion": "v1",
  "kind": "Pod",
  "metadata": {
    "name": "test-pod"
  },
  "spec": {
    "containers": [
      {
        "env": [
          {
            "name": "ENV",
            "value": "dev"
          }
        ],
        "image": "k8s.gcr.io/busybox",
        "name": "test-container"
      }
    ]
  }
}

But isn't Kubernetes accepting only YAML?

YAML is a superset of JSON and any JSON file is also a valid YAML file.

You can create the Pod in the cluster with the following commands:

dotnet run > pod.yaml
kubectl apply -f pod.yaml

Creating a custom Kubectl

Instead of exporting the JSON and feeding it to kubectl, you can send the payload to the cluster directly.

You can use the official Kubernetes client library to send the Pod definition to the cluster.

Assuming you are connected to a running cluster, you can create the pod by navigating to kubectl project and running it.

cd kubectl
dotnet build
dotnet run

And you can verify that the Pod was created with:

kubectl get pods

What's next

As you can imagine, this is a short demo and you can build more complex objects and use the power of dotnet to compose large objects from smaller ones.