Kuberenetes cluster on RaspberryPi the DevOps way

This repo installs K3S kubernetes cluster on 3 raspberry pi computers. I used recent raspberry pi model (4B) for this demo but you can install it on almost all modern raspberry pi models. (RPi 2,3 and 4)

We'd like to use DevOps/Cloud tools such as docker, packer and ansible to make it cool like we are running the cluster on our own home private cloud ;-)

Build the raspberry pi packer image

We're going to build rapsberry pi images by packer using packer-builder-arm-image repo.

Docker

Run the docker container to build the raspberry pi packer image:

cd packer/ && mkdir packer_cache output-arm-image

docker run \
  --rm \
  --privileged \
  -v ${PWD}:/build:rw \
  -v ${HOME}/.ssh:/build/.ssh:ro \
  -v ${PWD}/packer_cache:/build/packer_cache \
  -v ${PWD}/output-arm-image:/build/output-arm-image \
  -e RPI_HOSTNAME=raspberrypi.local \
  -e RPI_DHCP_DISABLE=true \
  -e RPI_INTERFACE=eth0 \
  -e RPI_IP_ADDRESS=192.168.1.1/24 \
  -e RPI_GATEWAY=192.168.1.1 \
  -e RPI_DNS_SERVERS=8.8.8.8 \
  -e UPDATE_PKGS=false \
  pyguy/packer-builder-arm build raspbian_kube.json

The image will be placed on output-arm-image directory.

Notes:

• You can use the following custom environment variables in the docker run command:

  Env name	Env value	Example	Required
  RPI_HOSTNAME	hostname	raspberrypi.local	Yes
  RPI_DHCP_DISABLE	true/false	true	No
  RPI_INTERFACE	network interface	eth0	No
  RPI_IP_ADDRESS	ip address with cidr	192.168.1.1/24	No
  RPI_GATEWAY	router gateway	192.168.1.1	No
  RPI_DNS_SERVERS	dns servers	8.8.8.8	No

• Your default public key will be added to the image, to add any other custom public keys to the image add the following variable to the following command: -var ssh_key_src=<custom public key file>

Setup the SD card

The following section is going to be used for all the nodes in the cluser. So let's do it one by one:

Flashing the SD card

We use Etcher for flashing the SD-cards. Just select the image file we built on output-arm-image/<hostname>.img, insert your SD-card, select the drive, and click “Flash!”. That's it!

Run K3S cluster with ansible

We use ansible roles for setting up the cluster.

Make inventory file

Copy the sample inventory file: cp inventory/hosts.ini.sample inventory/hosts.ini

and make sure that the inventory file is updated with your own hosts.

setup cluster

Run the following ansible playbook command:

ansible-plapybook -i inventory/hosts.ini site.yml

delete the cluster

Run the following ansible playbook command:

ansible-plapybook -i inventory/hosts.ini reset.yml

Provision k8s applications

Run the following command to install required collections:

ansible-galaxy install -r requirements.yml

Run the following ansible playbook command:

ansible-plapybook -i inventory/hosts.ini deploy.yml