Creating a Raspberry Pi Kubernetes Cluster: Installation

--- title: " Creating a Raspberry Pi cluster running Kubernetes, the installation (Part 2) " date: 2015-12-22 slug: creating-raspberry-pi-cluster-running url: /blog/2015/12/Creating-Raspberry-Pi-Cluster-Running author: > Arjen Wassink (Quintor) --- At Devoxx Belgium and Devoxx Morocco, [Ray Tsang](https://twitter.com/saturnism) and I ([Arjen Wassink](https://twitter.com/ArjenWassink)) showed a Raspberry Pi cluster we built at Quintor running HypriotOS, Docker and Kubernetes. While we received many compliments on the talk, the most common question was about how to build a Pi cluster themselves! We’ll be doing just that, in two parts. The [first part covered the shopping list for the cluster](https://kubernetes.io/blog/2015/11/creating-a-Raspberry-Pi-cluster-running-Kubernetes-the-shopping-list-Part-1), and this second one will show you how to get kubernetes up and running . . . Now you got your Raspberry Pi Cluster all setup, it is time to run some software on it. As mentioned in the previous blog I based this tutorial on the Hypriot linux distribution for the ARM processor. Main reason is the bundled support for Docker. I used [this version of Hypriot](http://downloads.hypriot.com/hypriot-rpi-20151004-132414.img.zip) for this tutorial, so if you run into trouble with other versions of Hypriot, please consider the version I’ve used. First step is to make sure every Pi has Hypriot running, if not yet please check the [getting started guide](http://blog.hypriot.com/getting-started-with-docker-on-your-arm-device/) of them. Also hook up the cluster switch to a network so that Internet is available and every Pi get an IP-address assigned via DHCP. Because we will be running multiple Pi’s it is practical to give each Pi a unique hostname. I renamed my Pi’s to rpi-master, rpi-node-1, rpi-node-2, etc for my convenience. Note that on Hypriot the hostname is set by editing the /boot/occidentalis.txt file, not the /etc/hostname. You could also set the hostname using the Hypriot flash tool. The most important thing about running software on a Pi is the availability of an ARM distribution. Thanks to [Brendan Burns](https://twitter.com/brendandburns), there are Kubernetes components for ARM available in the [Google Cloud Registry](https://cloud.google.com/container-registry/docs/). That’s great. The second hurdle is how to install Kubernetes. There are two ways; directly on the system or in a Docker container. Although the container support has an experimental status, I choose to go for that because it makes it easier to install Kubernetes for you. Kubernetes requires several processes (etcd, flannel, kubectl, etc) to run on a node, which should be started in a specific order. To ease that, systemd services are made available to start the necessary processes in the right way. Also the systemd services make sure that Kubernetes is spun up when a node is (re)booted. To make the installation real easy I created an simple install script for the master node and the worker nodes. All is available at [GitHub](https://github.com/awassink/k8s-on-rpi). So let’s get started now! ### Installing the Kubernetes master node First we will be installing Kubernetes on the master node and add the worker nodes later to the cluster. It comes basically down to getting the git repository content and executing the installation script. ``` $ curl -L -o k8s-on-rpi.zip https://github.com/awassink/k8s-on-rpi/archive/master.zip $ apt-get update $ apt-get install unzip $ unzip k8s-on-rpi.zip $ k8s-on-rpi-master/install-k8s-master.sh ``` The install script will install five services: * docker-bootstrap.service - is a separate Docker daemon to run etcd and flannel because flannel needs to be running before the standard Docker daemon (docker.service) because of network configuration. * k8s-etcd.service - is the etcd service for storing flannel and kubelet data. * k8s-flannel.service - is the flannel process providing an overlay network over all nodes in the cluster.

This blog post details how to set up a Kubernetes cluster on Raspberry Pi using HypriotOS, Docker, and Kubernetes. It provides instructions on configuring each Pi with a unique hostname, installing Kubernetes components from the Google Cloud Registry, and using systemd services to manage Kubernetes processes. The post includes commands for installing Kubernetes on the master node and setting up essential services like docker-bootstrap, k8s-etcd, and k8s-flannel.