Installing on Microk8s

This guide walks through the process of installing and configuring Microk8s and SpinKube.

Prerequisites

This guide assumes you are running Ubuntu 24.04, and that you have Snap enabled (which is the default).

The testing platform for this installation was an Akamai Edge Linode running 4G of memory and 2 cores.

Installing Spin

You will need to install Spin. The easiest way is to just use the following one-liner to get the latest version of Spin:

$ curl -fsSL https://developer.fermyon.com/downloads/install.sh | bash

Typically you will then want to move spin to /usr/local/bin or somewhere else on your $PATH:

$ sudo mv spin /usr/local/bin/spin

You can test that it’s on your $PATH with which spin. If this returns blank, you will need to adjust your $PATH variable or put Spin somewhere that is already on $PATH.

A Script To Do This

If you would rather work with a shell script, you may find this Gist a great place to start. It installs Microk8s and SpinKube, and configures both.

Installing Microk8s on Ubuntu

Use snap to install microk8s:

$ sudo snap install microk8s --classic

This will install Microk8s and start it. You may want to read the official installation instructions before proceeding. Wait for a moment or two, and then ensure Microk8s is running with the microk8s status command.

Next, enable the TLS certificate manager:

$ microk8s enable cert-manager

Now we’re ready to install the SpinKube environment for running Spin applications.

Installing SpinKube

SpinKube provides the entire toolkit for running Spin serverless apps. You may want to familiarize yourself with the SpinKube quickstart guide before proceeding.

First, we need to apply a runtime class and a CRD for SpinKube:

$ microk8s kubectl apply -f https://github.com/spinkube/spin-operator/releases/download/v0.4.0/spin-operator.runtime-class.yaml
$ microk8s kubectl apply -f https://github.com/spinkube/spin-operator/releases/download/v0.4.0/spin-operator.crds.yaml

Both of these should apply immediately.

We then need to install KWasm because it is not yet included with Microk8s:

$ microk8s helm repo add kwasm http://kwasm.sh/kwasm-operator/
$ microk8s helm install kwasm-operator kwasm/kwasm-operator --namespace kwasm --create-namespace --set kwasmOperator.installerImage=ghcr.io/spinkube/containerd-shim-spin/node-installer:v0.17.0
$ microk8s kubectl annotate node --all kwasm.sh/kwasm-node=true

The last line above tells Microk8s that all nodes on the cluster (which is just one node in this case) can run Spin applications.

Next, we need to install SpinKube’s operator using Helm (which is included with Microk8s).

$ microk8s helm install spin-operator --namespace spin-operator --create-namespace --version 0.4.0 --wait oci://ghcr.io/spinkube/charts/spin-operator

Now we have the main operator installed. There is just one more step. We need to install the shim executor, which is a special CRD that allows us to use multiple executors for WebAssembly.

$ microk8s kubectl apply -f https://github.com/spinkube/spin-operator/releases/download/v0.4.0/spin-operator.shim-executor.yaml

Now SpinKube is installed!

Running an App in SpinKube

Next, we can run a simple Spin application inside of Microk8s.

While we could write regular deployments or pod specifications, the easiest way to deploy a Spin app is by creating a simple SpinApp resource. Let’s use the simple example from SpinKube:

$ microk8s kubectl apply -f https://raw.githubusercontent.com/spinkube/spin-operator/main/config/samples/simple.yaml

The above installs a simple SpinApp YAML that looks like this:

apiVersion: core.spinkube.dev/v1alpha1
kind: SpinApp
metadata:
  name: simple-spinapp
spec:
  image: "ghcr.io/spinkube/containerd-shim-spin/examples/spin-rust-hello:v0.13.0"
  replicas: 1
  executor: containerd-shim-spin

You can read up on the definition in the documentation.

It may take a moment or two to get started, but you should be able to see the app with microk8s kubectl get pods.

$ microk8s kubectl get po
NAME                              READY   STATUS    RESTARTS   AGE
simple-spinapp-5c7b66f576-9v9fd   1/1     Running   0          45m

Troubleshooting

If STATUS gets stuck in ContainerCreating, it is possible that KWasm did not install correctly. Try doing a microk8s stop, waiting a few minutes, and then running microk8s start. You can also try the command:

$ microk8s kubectl logs -n kwasm -l app.kubernetes.io/name=kwasm-operator

Testing the Spin App

The easiest way to test our Spin app is to port forward from the Spin app to the outside host:

$ microk8s kubectl port-forward services/simple-spinapp 8080:80

You can then run curl localhost:8080/hello

$ curl localhost:8080/hello
Hello world from Spin!

Where to go from here

So far, we installed Microk8s, SpinKube, and a single Spin app. To have a more production-ready version, you might want to:

• Generate TLS certificates and attach them to your Spin app to add HTTPS support. If you are using an ingress controller (see below), here is the documentation for TLS config.
• Configure a cluster ingress
• Set up another Linode Edge instsance and create a two-node Microk8s cluster.

Bonus: Configuring Microk8s ingress

Microk8s includes an NGINX-based ingress controller that works great with Spin applications.

Enable the ingress controller: microk8s enable ingress

Now we can create an ingress that routes our traffic to the simple-spinapp app. Create the file ingress.yaml with the following content. Note that the service.name is the name of our Spin app.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: http-ingress
spec:
  rules:
    - http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: simple-spinapp
                port:
                  number: 80

Install the above with microk8s kubectl -f ingress.yaml. After a moment or two, you should be able to run curl [localhost](http://localhost) and see Hello World!.

Conclusion

In this guide we’ve installed Spin, Microk8s, and SpinKube and then run a Spin application.

To learn more about the many things you can do with Spin apps, go to the Spin developer docs. You can also look at a variety of examples at Spin Up Hub.

Or to try out different Kubernetes configurations, check out other installation guides.