Installing the Operating System

Prepare your Raspberry Pi nodes with a lightweight, 64-bit Linux OS ready for Kubernetes and K3s.

To run K3s reliably on Raspberry Pi, you’ll need a clean, minimal 64-bit Linux OS — with a few key configuration tweaks.

In this lesson, we’ll walk through choosing an operating system, installing it on each Pi, and preparing for clustering.

🧠 Recommended Operating Systems

⚠️ Ensure you’re using a 64-bit image, not 32-bit — Kubernetes requires 64-bit support.

💽 Step 1: Flash the OS

Tools You Can Use:

• Raspberry Pi Imager
• Balena Etcher
• dd (advanced)

Process:

1. Download the 64-bit OS image (e.g., Ubuntu Server 22.04 LTS for ARM).
2. Flash the image to each SD card or SSD.
3. Enable SSH:
   • For Raspberry Pi OS: place an empty file named ssh in the /boot partition.
   • For Ubuntu Server: SSH is enabled by default.

🧑‍💻 Step 2: First Boot and Configuration

1. Insert the card/SSD into each Pi.

2. Power up and SSH in:

   ssh ubuntu@<pi-ip-address>
   

   Default password: ubuntu (you’ll be prompted to change it)

3. Update the system:

   sudo apt update && sudo apt upgrade -y
   

4. Set a hostname for each Pi:

   sudo hostnamectl set-hostname pi-master
   sudo reboot
   

Use consistent names like pi-master, pi-node1, pi-node2, etc.

🌐 Step 3: Set Static IP or DHCP Reservation

On your router:

• Reserve an IP for each Raspberry Pi based on its MAC address
• This ensures stable node communication in the cluster

Or manually edit netplan (Ubuntu):

network:
  ethernets:
    eth0:
      dhcp4: no
      addresses: [192.168.1.101/24]
      gateway4: 192.168.1.1
      nameservers:
        addresses: [1.1.1.1, 8.8.8.8]
  version: 2

Save to /etc/netplan/00-installer-config.yaml and apply:

sudo netplan apply

🧹 Step 4: Recommended Cleanup and Config

• Enable cgroups (required for Kubernetes): Check /boot/firmware/cmdline.txt (Ubuntu) or /boot/cmdline.txt (Pi OS):

  Add or confirm:

  cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory
  

• Reboot:

  sudo reboot
  

🧪 Verify

After reboot, confirm:

• You can SSH into all nodes
• Hostnames are correct
• Static IPs are assigned
• cgroups are enabled

✅ Now your Pi cluster is ready for K3s installation!

Next up: Installing K3s

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