Using SpinKube on Kairos

By: Andrew Steurer

This is a guide that will help you get started running Spin applications on Kairos.

What is SpinKube?

(our open source dev tool for WebAssembly apps).

What is Kairos

or . For this demo, I used the kairos-ubuntu-24.04 image.

WARNING: SpinKube will not work with Kairos distributions that don’t use systemd (i.e. Alpine).

How to boot Kairos

When Kairos is initially booted, it will give you a few options for how to install Kairos. I recommend doing the interactive install:

You’ll notice at the bottom it starts to ask you some configuration questions. For this demo, I recommend that you match my configuration:

• 
  What’s the target install device?
  
  
  
  
  • Use the default value
  
  
  
  
  
  



• 
  
  Do you want to create any users? If not, system will not be accessible via terminal or ssh
  
  
  
  
  • Use the default value
  
  
  
  
  
  



• 
  
  User to setup
  
  
  
  
  • Use the default value
  
  
  
  
  
  



• 
  
  Password
  
  
  
  
  • Input a password you will remember
  
  
  
  
  
  



• 
  
  SSH access (rsakey, github/gitlab supported, comma-separated)
  
  
  
  
  • Input github:username, gitlab:username, and/or
    rsakey:YOUR_RSA_PUB_KEY
    
  
  
  
  
  
  



• 
  
  Make the user an admin (with sudo permissions)?
  
  
  
  
  • Use the default value
  
  
  
  
  
  



• 
  
  Do you want to setup a full mesh-support?
  
  
  
  
  • Use the default value
  
  
  
  
  
  



• 
  
  Do you want to enable k3s?
  
  
  
  
  • Use the default value
  
  
  
  
  
  



• 
  
  Are settings ok?
  
  
  
  
  • Input y
    
  
  
  
  
  
  

Once you finish and press enter, the system will need a moment to configure. After it’s finished, it will display # _ where you will then run sudo reboot. When it reboots and reaches the GNU GRUB screen, select the first option:

(a lightweight Kubernetes distribution), and will configure the Kairos SpinKube bundle we will install in a moment.

When the file is created, reboot your node.

Once the node is finished rebooting, run the command below to install the SpinKube bundle on K3S:

sudo kairos-agent install-bundle run://quay.io/kairos/community-bundles:spinkube_latest

Congrats! SpinKube is now running on your K3S node.

Testing the configuration

You can test the configuration on your node by creating a SpinApp manifest spin_app.yaml:

apiVersion: core.spinkube.dev/v1alpha1

kind: SpinApp

metadata:

  name: spin-app

spec:

  image: "ghcr.io/spinkube/spin-operator/hello-world:20241125-155422-g07a3175"

  replicas: 1

  executor: containerd-shim-spin

Once the .yaml file is created, run sudo k3s kubectl apply -f spin_app.yaml.

After a moment, you can run sudo k3s kubectl get pods which will show a pod named spin-app running in K3S.

Final thoughts

SpinKube is a powerful solution for edge computing because it combines the efficiency of WebAssembly with the high-availability of Kubernetes. Add these on top of the security and flexibility of Kairos, and you have resilient applications that can be tailored to the dynamic requirements of edge environments.