markdown Raspberry Pi Kubernetes Cluster v1

Posted 2021-05-06

# Raspberry Pi Kubernetes Cluster

## Hardware
 - Four Raspberry Pi 3's
 - TP-Link 8 Port Switch 
 - 6 Port USB Wall Charger 
 - Brass Spacer Standoff Assortment Kit
 - Four Samsung 32GB MicroSD EVO Select Memory Cards

## Software 
 - Ansible installed on a control PC/Mac
 - HypriotOS 
 - Kubectl installed on a control PC/Mac
 - [Kube on Arm](https://github.com/lahsivjar/kube-arm)

## Steps

### Step 1: Flash all SD cards with the HypriotOS
Install the [HypriotOS Flash Tool](https://github.com/hypriot/flash). With that tool installed I flashed all 4 SD cards:

```
$ flash --hostname node01-red https://github.com/hypriot/image-builder-rpi/releases/download/v1.7.1/hypriotos-rpi-v1.7.1.img.zip

$ flash --hostname node02-blue https://github.com/hypriot/image-builder-rpi/releases/download/v1.7.1/hypriotos-rpi-v1.7.1.img.zip

$ flash --hostname node03-green https://github.com/hypriot/image-builder-rpi/releases/download/v1.7.1/hypriotos-rpi-v1.7.1.img.zi

$ flash --hostname node04-black https://github.com/hypriot/image-builder-rpi/releases/download/v1.7.1/hypriotos-rpi-v1.7.1.img.zip
```

### Prepare Raspberry Pi Nodes
With the SD Cards prepared I powered up the Pi's and logged in to each using the default user `pirate` and the default password `hypriot`. I then changed the file `/etc/network/interfaces.d/eth0` file to set a static IP on each of the nodes. In my case it looked like this:

```
node01-red 192.168.0.120
node02-blue 192.168.0.121
node03-green 192.168.0.122
node04-black 192.168.0.123
```
With the static IPs set I rebooted each instance and then copied my local SSH key to each node. This is needed for the Ansible playbook to run properly. 

```
$ ssh-copy-id pirate@192.168.0.120
$ ssh-copy-id pirate@192.168.0.121
$ ssh-copy-id pirate@192.168.0.122
$ ssh-copy-id pirate@192.168.0.123
```

### Clone and edit Kubernetes on Arm Git Repo
We'll be using the a Git repo to deploy our Kubernetes cluster on the Pi's. First we need to clone the repo locally and update the `hosts.ini` file. 

```
$ git clone https://github.com/lahsivjar/kube-arm.git
$ cd kube-arm
$ cp hosts_sample.ini hosts.ini
```

Open up the `hosts.ini` file and update it with the node names and IPs:

```
[kube-master]
# List of master nodes
node01-red ansible_host=192.168.0.120 ansible_user=pirate

[kube-workers]
# List of worker nodes
node02-blue ansible_host=192.168.0.121 ansible_user=pirate
node03-green ansible_host=192.168.0.122 ansible_user=pirate
node04-black ansible_host=192.168.0.123 ansible_user=pirate

[kube:children]
# Don't change this section
kube-master
kube-workers

[kube:vars]
# Node on which ingress controller will be deployed, if it is configured
# Remove this variable if ingress controller is not to be installed
ingress_controller_node=node02-blue
```

With the `hosts.ini` file updated we can run our the ansible playbook:

```
$ ansible-playbook -i hosts.ini cluster-init.yaml
```

The playbook will take about 5-10 minutes to complete. When it completes I grab the Kubernetes configuration file from the master node and export it so I can use `kubectl` on my Macbook to interact with the cluster. 

```
$ scp 192.168.0.120:/home/pirate/.kube/config ~/homecluster.yml
$ export KUBECONFIG=/Users/ryan/homecluster.yml
```

With that all set I now test and make sure all nodes are online. 

```
$ kubectl get nodes
NAME           STATUS    ROLES     AGE       VERSION
node01-red     Ready     master    10m       v1.9.0
node02-blue    Ready     <none>    8m        v1.9.0
node03-green   Ready     <none>    8m        v1.9.0
node04-black   Ready     <none>    8m        v1.9.0
```

## Pictures

![Cluster with Parts](https://dsc.cloud/quickshare/ClusterParts.jpg)

![Cluster with spacers](https://dsc.cloud/quickshare/ClusterWithSpacers.jpg)

![Cluster with colored network cables](https://dsc.cloud/quickshare/ClusterWithNetworkCables.jpg)

![Switch](https://dsc.cloud/quickshare/Switch.jpg)

![Cluster Version 1](https://dsc.cloud/quickshare/ClusterVersion1.jpg)