Add documentation to install k3k on k3d

k3d is a valid local option for testing k3k. Adding documentation
on how to install k3k on top of k3d.

docs/install-k3d.md

@@ -0,0 +1,60 @@
+# How to install k3k on k3d
+
+This document provides a guide on how to install k3k on [k3d](https://k3d.io).
+
+## Installing k3d
+
+Since k3d uses docker under the hood, we need to expose the ports on the host that we'll then use for the NodePort in virtual cluster creation.
+
+Create the k3d cluster in the following way:
+
+```bash
+k3d cluster create k3k -p "30000-30010:30000-30010@server:0"
+```
+
+With this syntax ports from 30000 to 20010 will be exposed on the host.
+
+## Install k3k
+
+Install now k3k as usual:
+
+```bash
+helm repo update
+helm install --namespace k3k-system --create-namespace k3k k3k/k3k --devel
+```
+
+## Create a virtual cluster
+
+Once the k3k controller is up and running, create a namespace where to create our first virtual cluster.
+
+```bash
+kubectl create ns k3k-mycluster
+```
+
+Create then the virtual cluster exposing through NodePort one of the ports that we set up in the previous step:
+
+```bash
+cat <<EOF | kubectl apply -f -
+apiVersion: k3k.io/v1alpha1
+kind: Cluster
+metadata:
+  name: mycluster
+  namespace: k3k-mycluster
+spec:    
+  expose:
+    nodePort:
+      serverPort: 30001
+EOF
+```
+
+Check when the cluster is ready:
+
+```bash
+kubectl get po -n k3k-mycluster
+```
+
+Last thing to do is to get the kubeconfig to connect to the virtual cluster we've just created:
+
+```bash
+k3kcli kubeconfig generate --name mycluster --namespace k3k-mycluster --kubeconfig-server localhost:30001
+```