So we can used snap I'm using Ubuntu 20.04 as the Raspberry Pi operating system. For instructions on how to build the cluster and add nodes see the instructions on the Ubuntu site. It is key you set the cgroup flag for microk8s to run properly.
sudo snap install microk8s --classic --channel=latest/stable
Note: In order to use the add-on version of Traefik you need to be at least on channel 1.20+
so if you are already running microk8s at minimum you need the following upgrade
sudo snap refresh microk8s --classic --channel=1.20/stable
The tutorital above doesn't go through a few housekeeping item like adding users to the microk8s group and permissions so maybe revisit thost items here before continuing.
You will need to add at least 3 nodes to have a HA cluster you can find the latest documentation including the newly added failure domains on the microk8s site here.
So we'll need Helm for some items later so let's knock it out now.
microk8s enable helm3