K3s on Raspberry Pi - Initial Setup
As part of trying to learn more about Kubernetes, I thought it’d be interesting to setup a mini cluster running on Raspberry Pis. I had no real purpose for doing this, but figured it would be a good learning experience and would leave me with a somewhat realistic environment.
There are already a ton of great resources that cover various aspects of running Kubernetes on Raspberry Pi. This post is just a summary of the steps that worked for me for reference.
I decided a three node cluster would be enough to get started. Here are the items I purchased:
- 3 x Raspberry Pi 4 Model B (8GB)
- 3 x SanDisk MicroSD Card (32GB)
- 3 x Official US Raspberry Pi 4 Power Supply (5.1V 3A)
- 2 x Cluster Case for Raspberry Pi (with Fans)
Most likely the 4GB model would have been more than enough, but for $20 more you can double the RAM to 8GB. Also, I already had an 8-port switch with some ethernet cables, although each Pi also has on-board Wifi as an option.
The instructions for setting up the cluster case are available online. I think it could have been made a little simpler, but overall it wasn’t too hard. Pay close attention to the orientation of everything in the pictures.
Here is what my setup looked like after putting it together:
Raspberry Pi Setup
Before we can prepare the SD cards, we have to decide which operating system to use, which then leads to thinking about which Kubernetes distribution to use.
After doing some research, it seemed like there were two main options:
Raspberry Pi OS 64-bit+
Since Raspberry Pi OS is the official operating system, I decided to go with that and give K3s a try.
Image SD Cards
Download the latest 64-bit version of Raspberry Pi OS
- Use the Raspberry Pi Imager to image the SD cards
- Under Operating System, choose Use Custom
- Select the OS image downloaded in step 1
- Under Storage, select the SD card
- Customize settings by pressing
- Set a hostname like
rpi-1, enable password-based SSH
- Select Write to begin imaging
- Repeat the process for each SD card
Insert the SD cards into the Pis
Connect Pis to the switch with ethernet cables
Connect one ethernet cable from the switch to your home router
Connect a power supply to each Pi
- Plug the power supplies into outlets
At this point, the Pis should boot up and get assigned a dynamic IP address on your home network, just like any other device. You can use your router’s admin console to determine the IP addresses.
Once you have the IP addresses, you can test SSH to each one by running
ssh pi@<ip-address>, using the password you set when imaging the SD cards.
Assign Static IP Addresses
My router had a DHCP range of
192.168.1.255, so I adjusted the ending value to
192.168.1.235 in order to reserve some addresses for static assignment. That means we can pick three consecutive addresses somewhere between
For this example, we’ll use:
192.168.1.244 192.168.1.245 192.168.1.246
To set the static addresses, do the following:
SSH to the first Pi
sudo apt-get install vim
sudo vim /etc/dhcpcd.conf
Find the section for static address, uncomment and edit:
interface eth0 static ip_address=192.168.1.244/24 static routers=192.168.1.1 static domain_name_servers=192.168.1.1
192.168.1.1with your router’s IP address.
192.168.1.244with the static address for the first Pi.
Reboot the Pi
After waiting a minute or two, SSH with the static IP
Repeat the steps for each Pi.
/etc/hostsmappings on local machine
192.168.1.244 rpi-1 192.168.1.245 rpi-2 192.168.1.246 rpi-3
Create aliases in
~/.zshrcfor easy SSH access
alias sshrp1='ssh pi@rpi-1' alias sshrp2='ssh pi@rpi-2' alias sshrp3='ssh pi@rpi-3'
At this point you can test the SSH aliases to confirm that you can SSH to each Pi using a hostname mapped to the static IP address. For more detailed information, see Setting a Static IP Address on Raspberry Pi.
Setup Password-less SSH
This is not really a requirement to run Kubernetes, but it will be more convenient to not type passwords over and over, plus it will allow us to use Ansible to issue commands to the Raspberry Pi nodes.
Generate an SSH key on your local machine
Accept all the defaults and don’t enter a password.
This will produce
~/.ssh/id_rsa(private key) and
Copy the content of
mkdir ~/.ssh touch ~/.ssh/authorized_keys chmod 0700 ~/.ssh chmod 0600 ~/.ssh/authorized_keys vi ~/.ssh/authorized_keys
Paste contents of the copied
id_rsa.puband save the file.
Repeat the process for each Pi
At this point, you should be able to run any of the SSH aliases without entering a password.
I also followed a similar process to setup password-less SSH between all of the Raspberry Pi nodes, but this is also just a nice-to-have and not necessary.
For installing k3s, I used the k3s-ansible setup, which required that I get Ansible on my laptop. I already had
pip3 installed through
homebrew, so installing Ansible amounted to:
pip3 install ansible --user export PATH="/Users/bbende/Library/Python/3.7/bin:$PATH"
Now for running k3s-ansible…
Clone the k3s-ansible repo
Create the inventory by copying the example:
cp -R inventory/sample inventory/rpi
inventory/rpi/hosts.inito look like the following:
[master] 192.168.1.244 [node] 192.168.1.245 192.168.1.246 [k3s_cluster:children] master node
inventory/rpi/group_vars/all.ymlto set the k3s_version:
Launch the setup, this will take a few minutes:
ansible-playbook site.yml -i inventory/rpi/hosts.ini
Assuming the setup completed successfully, you can configure
kubectl on our local machine to connect to the k3s cluster.
Transfer the Kubeconfig from the master node to your local machine
scp [email protected]:~/.kube/config ~/.kube/config-rpi-k3s
KUBECONFIGenvironment variable in
export KUBECONFIG="~/.kube/config" export KUBECONFIG="$KUBECONFIG:~/.kube/config-rpi-k3s"
kubectlto check the available config contexts
kubectl config get-contexts CURRENT NAME CLUSTER AUTHINFO NAMESPACE * docker-desktop docker-desktop docker-desktop minikube minikube minikube rpi-k3s default default
If the name of the Raspberry Pi context is something different, you can rename it using the command:
kubectl config rename-context <CURRENT_NAME> <NEW_NAME>
kubectlto view the nodes of the
kubectl --context rpi-k3s get nodes NAME STATUS ROLES AGE VERSION rpi-3 Ready <none> 9d v1.21.0+k3s1 rpi-2 Ready <none> 9d v1.21.0+k3s1 rpi-1 Ready control-plane,master 9d v1.21.0+k3s1
At this point you should have a working k3s cluster to play around with.
As a next step, you can try following the k3s docs for installing the Kubernetes Dashboard.
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