Building a Raspberry Pi Kubernetes Cluster – Part 2 – Master Node

Building a Raspberry Pi Kubernetes Cluster - part 2 - master node title featured image

The Kubernetes Master node is one that runs what are known as the master processes: The kube-apiserver, kube-controller-manager and kube-scheduler.

In this post we’ll go through some common setup that all nodes (masters and workers) in your cluster should get, and then on top of that, the specific setup that will finally configure a single node in the cluster to be the master.

If you would like to jump to the other partes in this series, here are the links:

By now you should have some sort of stack or collection of Raspberry Pis going. As mentioned in the previous post, I used a Raspberry Pi 3 for my router/dhcp server for the Kubernetes Pi Cluster network, and Raspberry Pi 4’s with 4GB RAM each for the master and worker nodes. Here is how my stack looks now:

picture of raspberry pi devices in stack, forming the kubernetes cluster
The stack of Rasperry Pi’s in my cluster. Router Pi at the bottom, master and future worker nodes above. They’re sitting on top of the USB power hub and 8 port gigabit network switch

Common Setup

This setup will be used for both masters and workers in the cluster.

Start by writing the official Raspbian Buster Lite image to your microSD card. (I used the 26th September 2019 version), though as you’ll see next I also updated the Pi’s firmware and OS using the rpi-update command.

After attaching your Pi (master) to the network switch, it should pick up an IP address from the DHCP server you setup in part 1.

SSH into the Pi and complete the basic setup such as setting a hostname and ensuring it gets a static IP address lease from DHCP by editing your dnsmasq configuration (as per part 1).

Note: As the new Pi is running on a different network behind your Pi Router, you can either SSH into your Pi Router (like a bastion host or jump box) and then SSH into the new Master Pi node from there.

Now update it:

sudo rpi-update

After the update completes, reboot the Pi.

sudo reboot now

SSH back into the Pi, then download and install Docker. I used version 19.03 here, though at the moment it is not ‘officially’ supported.

export VERSION=19.03
curl -sSL | sh && sudo usermod pi -aG docker && newgrp docker

Kubernetes nodes should have swap disabled, so do that next. Additionally, you’ll enable control groups (cgroups) for resource isolation.

sudo dphys-swapfile swapoff
sudo dphys-swapfile uninstall
sudo update-rc.d dphys-swapfile remove
sudo systemctl disable dphys-swapfile.service

sudo sed -i -e 's/$/ cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory/' /boot/cmdline.txt

Installing kubeadm and other Kubernetes components

Next you’ll install the kubeadm tool (helps us create our cluster quickly), as well as a bunch of other components required, such as the kubelet (the main node agent that registers nodes with the API server among other things), kubectl and the kubernetes cni (to provision container networking).

Next up, install the legacy iptables package and setup networking so that it traverses future iptables rules.

Note: when I built my cluster initially I discovered problems with iptables later on, where the kube-proxy and kubelet services had trouble populating all their required iptables rules using the pre-installed version of iptables. Switching to legacy iptables fixed this.

The error I ran into (hopefully those searching it will come across this post too) was:

proxier.go:1423] Failed to execute iptables-restore: exit status 2 (iptables-restore v1.6.0: Couldn't load target `KUBE-MARK-DROP':No such file or directory

Setup iptables and change it to the legacy version:

sudo sysctl net.bridge.bridge-nf-call-iptables=1
sudo update-alternatives --set iptables /usr/sbin/iptables-legacy

Lastly to finish off the common (master or worker) node setup, reboot.

sudo reboot now

Master Node Setup

Now you can configure this Pi as a master Kubernetes node. SSH back in after the reboot and pull down the various node component docker images, then initialise it.

Important: Make sure you change the IP address in the below code snippet to match whatever IP address you reserved for this master node in your dnsmasq leases configuration. This is the IP address that the master API server will advertise out with.

Note: In my setup I am using as the pod CIDR (overlay network). This is specifically to keep it separate from my internal Pi network of

sudo kubeadm config images pull -v3
sudo kubeadm init --token-ttl=0 --apiserver-advertise-address= --pod-network-cidr=

# capture text and run as normal user. e.g.:
# mkdir -p $HOME/.kube
# sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
# sudo chown $(id -u):$(id -g) $HOME/.kube/config

Once the kubeadm commands complete, the init command will output a bunch of commands to run. Copy and enter them afterwards to setup the kubectl configuration under $HOME/.kube/config.

You’ll also see a kubeadm join command/token. Take note of that and keep it safe. You’ll use this to join other workers to the cluster later on.

kubeadm join --token yi4hzn.glushkg39orzx0fk \
    --discovery-token-ca-cert-hash sha256:xyz0721e03e1585f86e46e477de0bdf32f59e0a6083f0e16871ababc123

Installing the CNI (Weave)

You’ll setup Weave Net next. At a high level, Weave Net creates a virtual container network that connects your containers that are scheduled across (potentially) many different hosts and enables their automatic discovery across these hosts too.

Kubernetes has a pluggable architecture for container networking, and Weave Net is one implementation of this.

Note: the command below assumes you’re using an overlay/container network of Change this if you’re not using this range.

On your Pi master node:

curl --location -o ./weave-cni.yaml "$(kubectl version | base64 | tr -d '\n')&env.IPALLOC_RANGE="
kubectl apply -f ./weave-cni.yaml

After a few moments waiting for your node to pull down the weave net container images, check that the weave container(s) are running and that the master node is showing as ready. Here is how that should look…

kubectl -n kube-system get pods
kubectl get nodes
pi@korben:~ $ kubectl -n kube-system get pods | grep weave
weave-net-cfxhr                  2/2     Running   20         10d
weave-net-chlgh                  2/2     Running   17         23d
weave-net-rxlg8                  2/2     Running   13         23d

pi@korben:~ $ kubectl get nodes
korben   Ready    master   23d   v1.16.2

That is pretty much it for the master node setup. You now have a single master node running the Kubernetes master components / API server, and have even used to successfully provision and configure container networking.

As a result of deploying Weave Net, you now have a DaemonSet that will ensure that any new node that joins the cluster will automatically get the Weave Net CNI. All other nodes in the cluster will automatically update to ‘know’ about the new node and subsequently containers in the cluster will be able to talk to each other over the overlay network.


  1. Hey Pedro,

    In my setup, I’ve got a NAS server with two NICs. One network interface is connected into the pi k8s network (, and the other network interface is connected to my home network (switch on my home network).

    This way I can have the pi k8s devices mount NFS storage on, (e.g. using NFS provisioned PVCs in my k8s cluster) and I can also access my NAS storage from my home network on Here is a screenshot that shows the two interfaces:

    Using iptables rules it is possible to forward network traffic from the home network into the k8s pi cluster network – that part I cover in the part 1, routing post.

    Hope that helps!

  2. Hi,

    Having the pod CIDR and your home network (as per 1st part) doesn’t cause troubles to access the ‘home’ network (192.168.2..) from the k8s cluster?

    I followed your guide and, from the k8s master, I can ping the internet, the router, but any attempt to my NAS (not behind the router setup as the leel00 of part 1) fails.

    Accessing a service on the cluster from outside the subnet works as per the 4th section of your guide.

    Any idea?

  3. Can you tell me how i can access a Application in the Cluster?
    I have Ingress Controller Configured in the Cluster, like you describe it.

    For a Demo i installed Kubernetes-dashboard and defined a ingress for it whitch listen on Port 80. How can i reach it now from my browser?

  4. Thanks for posting the fix for the newer version Juli. Another way would be to pin the version specified in the curl command used to retrieve the YAML file :+1:

  5. The Command for installing weave don´t works…
    When you apply the weave-cni.yaml the pod runs into a CrashBackLoopOf.

    This is causing a newer Version gets downloaded (2.7.0) and i think that the Parameter for &env.IPALLOC_RANGE did not work.

    The solution is:
    Modify the weave-cni.yaml with nano weave-cni.yaml and change the
    image: ‘’


    image: ‘’

    You need to modify this in two Lines !

    After saving the changes you can apply the yaml and it works fine 🙂

    Best Regards,

    I hope this helps you.

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