Lesson 5: Flashing Raspberry Pi OS and Initial Configuration

In this lesson, you will follow a step-by-step guide to install Raspberry Pi OS on your devices, configure essential settings, and prepare them for networking.

This is the 5th lesson of the guide Building a production-ready Kubernetes cluster from scratch. Make sure you have completed the previous lesson before continuing here. The full list of lessons in the guide can be found in the overview.

Now that your Raspberry Pi devices are unboxed, assembled, and connected, it’s time to install the operating system. In this lesson, we’ll walk through the process of flashing Raspberry Pi OS onto your microSD cards and performing the initial configuration needed to prepare your devices for the Kubernetes cluster.

Preparing the MicroSD Cards

To begin, you need to prepare the microSD cards that will host the Raspberry Pi OS using the Raspberry Pi Imager. In addition to the OS we will also set up the SSH access for headless setup and a hostname for each Raspberry Pi.

• Insert each microSD card into your computer using a card reader.
• Download and install the Raspberry Pi Imager for your operating system (if you haven’t already).
• Open the Raspberry Pi Imager and select the Raspberry Pi OS (other) option.
• Choose the Raspberry Pi OS Lite (64-bit) version (or 32-bit for older models) for a minimal installation.
• Select the microSD card you want to flash the OS to (ensure you have the correct card selected), and click on Next.
• When prompted to use OS customization, click on Edit Settings.
• In the OS customisation settings window, configure the following settings in General:
  • Hostname: Set a unique hostname for each Raspberry Pi device kubernetes-node-X (replacing X with the number of the current node).
  • Username: Set the username to pi and configure a unique password. Ideally you configure a different password for each node, but for simplicity you can use the same password for all node for now.
  • Timezone: Set the timezone to your local timezone.
• In the OS customisation settings window, switch to the tab Services and enable SSH to allow remote access to the Raspberry Pi devices.
  • Generate a new SSH key pair using ssh-keygen or use an existing one to secure the SSH connection. If you are creating a new key pair and write it to ~/.ssh/k8s_cluster_id_ed25519.
  • Open the public key ~/.ssh/k8s_cluster_id_ed25519.pub and copy its content into the textfield. Click on Save to confirm the changes.
• Back on the main screen, when prompted with “Would you like to apply OS customizations settings?”, click on Yes.
• A warning will be shown, explaining that all data on the microSD card will be erased. Click on Yes to confirm and start the flashing process.
• Once the flashing process is complete, the microSD card will be ejected automatically. Remove the card from your computer and insert it again to edit the boot configuration for additional settings.

TIP: Add a label to your Raspberry Pi to identify the device by its hostname. This will help you distinguish between the devices when connecting to them remotely.

Pre-Configure Static IP Addresses

Instead of using DHCP to assign IP addresses to the Raspberry Pi devices, you can configure static IP addresses to ensure that each device has a consistent address on the network. This is particularly useful when setting up a Kubernetes cluster, as it allows you to easily identify and connect to each node.

As we have disabled the DHCP service on the router, we need to configure the static IP addresses on the Raspberry Pi devices directly. So that it is already configured on the first boot.

After you mounted the microSD card again, the boot partition should be mounted as bootfs. The Raspberry Pi Imager should have created a file firstrun.sh, which is used to configure the Raspberry Pi on first boot.

Open firstrun.sh in your text editor of choice. Then right before the deletion of the script rm -f /boot/firstrun.sh, add the following lines to configure a static IP address. Make sure to replace X with the corresponding number for each Raspberry Pi device:

# START - Configure a static IP address for eth0
echo "Enabling and starting NetworkManager..."
systemctl enable NetworkManager
systemctl start NetworkManager

# IMPORTANT: Replace `X` with the number of the node
NODE_IP_ADDRESS="10.1.1.X/16"
echo "Configuring static IP $NODE_IP_ADDRESS for eth0..."
/usr/bin/nmcli connection modify "Wired connection 1" ipv4.method manual ipv4.addresses $NODE_IP_ADDRESS ipv4.gateway "10.1.0.1" ipv4.dns "10.1.0.1" autoconnect yes

echo "Bringing up the connection..."
nmcli connection up "Wired connection 1"

echo "Static IP configuration applied."
# END - Configure a static IP address for eth0

Save the changes and safely eject the microSD card from your computer.

Verifying Connectivity

Insert the microSD card into the Raspberry Pi device and power it on. To verify that each Raspberry Pi is correctly configured and accessible, ping each Raspberry Pi from your main computer or from one Raspberry Pi to another to ensure network connectivity.

$ ping 10.1.1.X

Connect to the Raspberry Pi devices using SSH to confirm that you can access them remotely:

$ ssh -i ~/.ssh/k8s_cluster_id_ed25519 [email protected]

If all devices respond successfully, your network configuration is correct, and your Raspberry Pi devices are ready for the next steps.

Debian GNU/Linux 11 kubernetes-node-X tty1

My IP address is 10.1.1.X

kubernetes-node-X login:

Lesson Conclusion

Congratulations! With the operating system flashed and the initial configuration complete, you are now ready to set up the NVMe SSDs for persistent storage. You have completed this lesson and you can now continue with the next one.