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Raspberry Pi K3s Cluster Setup

Easily bootstrap a Kubernetes (K3s) cluster on multiple Raspberry Pi boards with a single script.

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🚀 Purpose

This project provides a fully automated Bash script to:

• Prepare any number of Raspberry Pi nodes for Kubernetes (enable cgroups, disable swap, set hostnames, etc.)
• Install K3s on the master node
• Join all worker nodes automatically
• Ensure best practices for security and repeatability

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🛠️ Prerequisites

• Each Raspberry Pi must be flashed with Raspberry Pi OS Lite (32 or 64 bits depending on your model; check compatibility).

⚠️ Important: You must be able to connect to each Raspberry Pi via SSH without a password (using an SSH key). This means the SSH private key from your installation machine (e.g., your MacBook or PC) must have its public part (id_rsa.pub or similar) copied to the ~/.ssh/authorized_keys file of the user on each Pi. Password authentication is not supported by this script.

• You must retrieve the IP addresses of all Raspberry Pi boards on your network before running the script.
• You must have an SSH private key on your local machine that allows access to all Raspberry Pi nodes (the public part of this key must be present in ~/.ssh/authorized_keys on each Pi). The script uses this key to connect to each Pi; by default, it expects ~/.ssh/id_rsa, but you can modify the script to use another key if needed.
• All Raspberry Pi accessible via SSH (same user, SSH key-based auth recommended)
• Your user must have passwordless sudo on all Pis
• The following tools must be installed on your local machine:

Tool	Purpose	Install Command (Debian/Ubuntu)
k3sup	K3s install/join helper	`curl -sLS https://get.k3sup.dev
ssh	Remote command exec	Already installed on most systems
scp	Copy files over SSH	Already installed on most systems

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⚡ Installation of Dependencies

# Install k3sup
curl -sLS https://get.k3sup.dev | sh
sudo install -m 755 k3sup /usr/local/bin/

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📄 Usage

1. Clone this repository
2. Edit your SSH keys and ensure access to all Raspberry Pi nodes
3. Run the script with your parameters:

./k3s-setup.sh \
  --rpi-ips "192.168.1.101 192.168.1.102 192.168.1.103 192.168.1.104 192.168.1.105" \
  --rpi-user pi \
  --node-name-scheme rpi-node- \
  --sleep-duration 60

• --rpi-ips : Space-separated list of all Raspberry Pi IP addresses (first is master)
• --rpi-user : Username for SSH (must have sudo rights)
• --node-name-scheme : Prefix for node hostnames (e.g. rpi-node- → rpi-node-1, rpi-node-2, ...)
• --sleep-duration : Time (in seconds) to wait after rebooting all Pis

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📝 What the Script Does

1. Enables cgroups on all Pis for container support
2. Disables swap permanently
3. Configures passwordless sudo for the user
4. Sets unique hostnames for each Pi
5. Reboots all Pis
6. Checks cgroups activation
7. Installs K3s on the master node
8. Joins all workers to the cluster
9. Prints the command to copy your kubeconfig

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📦 Example Output

→ Enabling cgroups on 192.168.1.101 ...
→ Disabling swap on 192.168.1.101 ...
→ Configuring passwordless sudo for pi on 192.168.1.101 ...
→ Setting hostname of 192.168.1.101 to rpi-node-1 ...
→ Rebooting 192.168.1.101 ...
⏳ Waiting 60s for Pis to reboot...
→ Installing k3s server on 192.168.1.101 ...
→ Bootstrapping k3s via k3sup on all nodes ...
   → Joining worker 192.168.1.102 (expected hostname: rpi-node-2) ...
✅ K3s cluster installed. Copy kubeconfig from master for kubectl:
   scp pi@192.168.1.101:/etc/rancher/k3s/k3s.yaml ~/.kube/config

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⚠️ Security Warning

Never commit your kubeconfig or any secret to GitHub! This file gives full access to your cluster.

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🙏 Credits

• Inspired by the k3sup project

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👤 Author

PopArchi
aka Zakaria RACHEDI

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📬 Issues & Contributions

Feel free to open issues or PRs to improve this script!