Learn how to install k3s on Ubuntu running on Raspberry Pi, including setup for control plane and agents. Follow this guide for a smooth installation process.

After reinstalling all of my nodes with Ubuntu, it’s time to install k3s. Here’s a step-by-step guide to get it running smoothly.

Installing Needed Modules

Per k3s#4234, k3s requires some extra modules that aren’t installed by default on Ubuntu. Install them with:

bash
sudo apt install linux-modules-extra-raspi

Installing k3s Control Plane

Follow the instructions from the Rancher k3s Quick-Start Guide.

On the first node, run:

bash
curl -sfL https://get.k3s.io | sh -

Then wait, occasionally running:

bash
sudo k3s kubectl get nodes

to check on progress.

Installing k3s Agents

Once the control plane is up, grab the server token:

bash
sudo cat /var/lib/rancher/k3s/server/node-token

On the other nodes, run:

bash
curl -sfL https://get.k3s.io | K3S_URL=https://rpi401:6443 K3S_TOKEN=<node-token> sh -

Setting Up KUBECONFIG

Back on the primary node:

bash
mkdir ~/.k3s
sudo cp /etc/rancher/k3s/k3s.yaml ~/.k3s/k3s.yaml
sudo chown $USER.$USER ~/.k3s/k3s.yaml
export KUBECONFIG=$HOME/.k3s/k3s.yaml   # add this to ~/.bashrc

Enabling Shell Auto-Completion

Follow the instructions from the Kubernetes documentation:

bash
echo 'source <(kubectl completion bash)' >>~/.bashrc

Checking if it Works

Finally, verify the setup by running:

bash
kubectl get nodes

Example output:

NAME     STATUS   ROLES                  AGE   VERSION
rpi401   Ready    control-plane,master   80m   v1.21.7+k3s1
rpi405   Ready    <none>                 28s   v1.21.7+k3s1
rpi404   Ready    <none>                 18s   v1.21.7+k3s1
rpi403   Ready    <none>                 18s   v1.21.7+k3s1
rpi402   Ready    <none>                 32s   v1.21.7+k3s1

By following these steps, you can successfully install k3s on Ubuntu running on Raspberry Pi, setting up both the control plane and agents effectively.