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2nd chunk of `content/en/blog/_posts/2015-12-00-Creating-Raspberry-Pi-Cluster-Running.md`
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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.
* docker.service - is the standard Docker daemon, but with flannel as a network bridge. It will run all Docker containers.
* k8s-master.service - is the kubernetes master service providing the cluster functionality.

The basic details of this installation procedure is also documented in the [Getting Started Guide](https://github.com/kubernetes/kubernetes/blob/release-1.1/docs/getting-started-guides/docker-multinode/master.md) of Kubernetes. Please check it to get more insight on how a multi node Kubernetes cluster is setup.


Let’s check if everything is working correctly. Two docker daemon processes must be running.

```
$ ps -ef|grep docker
root       302     1  0 04:37 ?        00:00:14 /usr/bin/docker daemon -H unix:///var/run/docker-bootstrap.sock -p /var/run/docker-bootstrap.pid --storage-driver=overlay --storage-opt dm.basesize=10G --iptables=false --ip-masq=false --bridge=none --graph=/var/lib/docker-bootstrap

root       722     1 11 04:38 ?        00:16:11 /usr/bin/docker -d -bip=10.0.97.1/24 -mtu=1472 -H fd:// --storage-driver=overlay -D
```



The etcd and flannel containers must be up.
```
$ docker -H unix:///var/run/docker-bootstrap.sock ps

CONTAINER ID        IMAGE                        COMMAND                  CREATED             STATUS              PORTS               NAMES

4855cc1450ff        andrewpsuedonym/flanneld     "flanneld --etcd-endp"   2 hours ago         Up 2 hours                              k8s-flannel

ef410b986cb3        andrewpsuedonym/etcd:2.1.1   "/bin/etcd --addr=127"   2 hours ago         Up 2 hours                              k8s-etcd


The hyperkube kubelet, apiserver, scheduler, controller and proxy must be up.

$ docker ps

CONTAINER ID        IMAGE                                           COMMAND                  CREATED             STATUS              PORTS               NAMES

a17784253dd2        gcr.io/google\_containers/hyperkube-arm:v1.1.2   "/hyperkube controller"   2 hours ago         Up 2 hours                              k8s\_controller-manager.7042038a\_k8s-master-127.0.0.1\_default\_43160049df5e3b1c5ec7bcf23d4b97d0\_2174a7c3
Title: Installing Kubernetes Master Node
Summary
This section details how to install Kubernetes on the master node of a Raspberry Pi cluster. It involves downloading and executing an installation script from GitHub, which sets up five essential services: docker-bootstrap, k8s-etcd, k8s-flannel, docker, and k8s-master. The procedure is based on running Kubernetes in Docker containers for easier installation. The post also includes commands to verify that the Docker daemons, etcd, flannel, kubelet, apiserver, scheduler, controller, and proxy are running correctly.