How to install K3s

Step 1: Update Ubuntu system

Update and upgrade your system

sudo apt update && sudo apt -y upgrade
sudo reboot

Step 2: Install Single Node k3s Kubernetes

We will deploy a single node kubernetes using k3s lightweight tool. K3s is a certified Kubernetes distribution designed for production workloads in unattended, resource-constrained environments. The good thing with k3s is that you can add more Worker nodes at later stage if need arises.

K3s provides an installation script that is a convenient way to install it as a service on systemd or openrc based systems

Let’s run the following command to install K3s on our Ubuntu system:

curl -sfL https://get.k3s.io | sudo bash -
sudo chmod 644 /etc/rancher/k3s/k3s.yaml

Installation process output:

[INFO]  Finding release for channel stable
[INFO]  Using v1.21.3+k3s1 as release
[INFO]  Downloading hash https://github.com/k3s-io/k3s/releases/download/v1.21.3+k3s1/sha256sum-amd64.txt
[INFO]  Downloading binary https://github.com/k3s-io/k3s/releases/download/v1.21.3+k3s1/k3s
[INFO]  Verifying binary download
[INFO]  Installing k3s to /usr/local/bin/k3s
[INFO]  Creating /usr/local/bin/kubectl symlink to k3s
[INFO]  Creating /usr/local/bin/crictl symlink to k3s
[INFO]  Creating /usr/local/bin/ctr symlink to k3s
[INFO]  Creating killall script /usr/local/bin/k3s-killall.sh
[INFO]  Creating uninstall script /usr/local/bin/k3s-uninstall.sh
[INFO]  env: Creating environment file /etc/systemd/system/k3s.service.env
[INFO]  systemd: Creating service file /etc/systemd/system/k3s.service
[INFO]  systemd: Enabling k3s unit
Created symlink /etc/systemd/system/multi-user.target.wants/k3s.service → /etc/systemd/system/k3s.service.
[INFO]  systemd: Starting k3s

Validate K3s installation:

The next step is to validate our installation of K3s using kubectl command which was installed and configured by installer script.

$ kubectl get nodes
NAME        STATUS   ROLES                  AGE   VERSION
ubuntu-01   Ready    control-plane,master   33s   v1.22.5+k3s1

You can also confirm Kubernetes version deployed using the following command:

$ kubectl version --short
Client Version: v1.22.5+k3s1
Server Version: v1.22.5+k3s1

The K3s service will be configured to automatically restart after node reboots or if the process crashes or is killed.