2/17/2018 - 6:48 PM

K8s on Raspbian

K8s on Raspbian

K8s on (vanilla) Raspbian Lite

Yes - you can create a Kubernetes cluster with Raspberry Pis with the default operating system Raspbian. Carry on using all the tools and packages you're used to with the officially-supported OS.


  • You must use an RPi2 or 3 for Kubernetes
  • I'm assuming you're using wired ethernet (Wi-Fi also works)

Master node setup

  • Flash Raspbian to a fresh SD card.

You can use to burn the SD card.

Before booting set up an empty file called ssh in /boot/ on the SD card.

Use Raspbian Stretch Lite

Update: I previously recommended downloading Raspbian Jessie instead of Stretch. At time of writing (3 Jan 2018) Stretch is now fully compatible.

  • Change hostname

Use the raspi-config utility to change the hostname to k8s-master-1 or similar and then reboot.

  • Set a static IP address

It's not fun when your cluste breaks because the IP of your master changed. Let's fix that problem ahead of time:

cat >> /etc/dhcpcd.conf

Paste this block:

profile static_eth0
static ip_address=
static routers=
static domain_name_servers=

Hit Control + D.

Change 100 for 101, 102, 103 etc.

You may also need to make a reservation on your router's DHCP table so these addresses don't get given out to other devices on your network.

  • Install Docker

This installs 17.12 or newer.

$ curl -sSL | sh && \
sudo usermod pi -aG docker
  • Disable swap

For Kubernetes 1.7 and newer you will get an error if swap space is enabled.

Turn off swap:

$ sudo dphys-swapfile swapoff && \
  sudo dphys-swapfile uninstall && \
  sudo update-rc.d dphys-swapfile remove

This should now show no entries:

$ sudo swapon --summary
  • Edit /boot/cmdline.txt

Add this text at the end of the line, but don't create any new lines:

cgroup_enable=cpuset cgroup_enable=memory

Some people in the comments suggest cgroup_memory=memory should now be: cgroup_memory=1.

Now reboot - do not skip this step.

  • Add repo lists & install kubeadm
$ curl -s | sudo apt-key add - && \
  echo "deb kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list && \
  sudo apt-get update -q && \
  sudo apt-get install -qy kubeadm

I realise this says 'xenial' in the apt listing, don't worry. It still works.

  • You now have two new commands installed:

  • kubeadm - used to create new clusters or join an existing one

  • kubectl - the CLI administration tool for Kubernetes

  • Initialize your master node:

$ sudo kubeadm init --token-ttl=0

We pass in --token-ttl=0 so that the token never expires - do not use this setting in production. The UX for kubeadm means it's currently very hard to get a join token later on after the initial token has expired.

Optionally also pass --apiserver-advertise-address= with the IP of the Pi.

Note: This step will take a long time, even up to 15 minutes.

After the init is complete run the snippet given to you on the command-line:

  mkdir -p $HOME/.kube
  sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
  sudo chown $(id -u):$(id -g) $HOME/.kube/config

This step takes the key generated for cluster administration and makes it available in a default location for use with kubectl.

  • Now save your join-token

Your join token is valid for 24 hours, so save it into a text file. Here's an example of mine:

$ kubeadm join --token 9e700f.7dc97f5e3a45c9e5 --discovery-token-ca-cert-hash sha256:95cbb9ee5536aa61ec0239d6edd8598af68758308d0a0425848ae1af28859bea
  • Check everything worked:
$ kubectl get pods --namespace=kube-system
NAME                           READY     STATUS    RESTARTS   AGE                
etcd-of-2                      1/1       Running   0          12m                
kube-apiserver-of-2            1/1       Running   2          12m                
kube-controller-manager-of-2   1/1       Running   1          11m                
kube-dns-66ffd5c588-d8292      3/3       Running   0          11m                
kube-proxy-xcj5h               1/1       Running   0          11m                
kube-scheduler-of-2            1/1       Running   0          11m                
weave-net-zz9rz                2/2       Running   0          5m 

You should see the "READY" count showing as 1/1 for all services as above. DNS uses three pods, so you'll see 3/3 for that.

  • Setup networking

Install Weave network driver

$ kubectl apply -f

If you run into an issue use this script instead:

$ kubectl apply -f \
 "$(kubectl version | base64 | tr -d '\n')"

Join other nodes

On the other RPis, repeat everything apart from kubeadm init.

  • Change hostname

Use the raspi-config utility to change the hostname to k8s-worker-1 or similar and then reboot.

  • Join the cluster

Replace the token / IP for the output you got from the master node:

$ sudo kubeadm join --token 1fd0d8.67e7083ed7ec08f3

You can now run this on the master:

$ kubectl get nodes
k8s-1     Ready      5m        v1.7.4
k8s-2     Ready      10m       v1.7.4

Deploy a container


apiVersion: v1
kind: Service
  name: markdownrender
    app: markdownrender
  type: NodePort
    - port: 8080
      protocol: TCP
      targetPort: 8080
      nodePort: 31118
    app: markdownrender
apiVersion: apps/v1beta1 # for versions before 1.6.0 use extensions/v1beta1
kind: Deployment
  name: markdownrender
  replicas: 1
        app: markdownrender
      - name: markdownrender
        image: functions/markdownrender:latest-armhf
        imagePullPolicy: Always
        - containerPort: 8080
          protocol: TCP

Deploy and test:

$ kubectl create -f function.yml
$ curl -4 http://localhost:31118 -d "# test"

From a remote machine such as your laptop use the IP address of your Kubernetes master and try the same again.

Start up the dashboard

The dashboard can be useful for visualising the state and health of your system but it does require the equivalent of "root" in the cluster. If you want to proceed you should first run in a ClusterRole from the docs.

echo -n 'apiVersion:
kind: ClusterRoleBinding
  name: kubernetes-dashboard
    k8s-app: kubernetes-dashboard
  kind: ClusterRole
  name: cluster-admin
- kind: ServiceAccount
  name: kubernetes-dashboard
  namespace: kube-system' | kubectl apply -f -

This is the development/alternative dashboard which has TLS disabled and is easier to use.

$ kubectl apply -f

You can then find the IP and port via kubectl get svc -n kube-system. To access this from your laptop you will need to use kubectl proxy and navigate to http://localhost:8001/ on the master, or tunnel to this address with ssh.

Remove the test deployment

Now on the Kubernetes master remove the test deployment:

$ kubectl delete -f function.yml

Moving on

Now head back over to the tutorial and deploy OpenFaaS


# This installs the base instructions up to the point of joining / creating a cluster

curl -sSL | sh && \
  sudo usermod pi -aG docker

sudo dphys-swapfile swapoff && \
  sudo dphys-swapfile uninstall && \
  sudo update-rc.d dphys-swapfile remove

curl -s | sudo apt-key add - && \
  echo "deb kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list && \
  sudo apt-get update -q && \
  sudo apt-get install -qy kubeadm
echo Adding " cgroup_enable=cpuset cgroup_memory=1" to /boot/cmdline.txt

sudo cp /boot/cmdline.txt /boot/cmdline_backup.txt
orig="$(head -n1 /boot/cmdline.txt) cgroup_enable=cpuset cgroup_memory=1"
echo $orig | sudo tee /boot/cmdline.txt

echo Please reboot

Use this to setup quickly

# curl -sL \ \
 | sudo sh