README.md

Kubernetes based Whac-a-mole game

This is whac-a-mole game with Kubernetes running in the background.

Each mole is a kubernetes pod. The goal is to kill the pods faster than kubernetes can deploy new ones.

Example

Explanation of the application

This repository is split into three applications.

Mole pod

This is a very basic flask application which is dockerized.
It contains three endpoints: /health, /kill and /shutdown.
This application is than build as a docker image and ran as a pod in Kubernetes.
In the final web interface, a mole is molepod container.

Mole relay

Again a very basic flask application which is dockerized.
It contains two endpoints: / and /health.
The purpose of this application is to be the bridge between the host and the minikube environment.
Meaning that when we want to access a mole pod, we actually make the request through a container
with the docker image of this mole relay program.

Mole game

This application contains most of the logic.
Based on the configuration given by the command line arguments, it starts the two pods(mole pod and mole relay).
Once the pods are deployed, the front end flask app is launched.
Here we can access our whac a mole interface.
When we press a mole, a kill or shutdown command is send through the server, to the relay, to finally end up at the specific container in the mole pod.
Once the mole pod is down, kubernetes will take care to relaunch it.

Requirements

1. Python3.7
2. Docker
3. Minikube
4. Google Chrome

General instructions

Terminal commands to get a working Minikube

Note that the application expects the application to be launched from within a folder of the project root "whac-a-mole-kubernetes". If you change the project folders name, you do not only have to change the upcoming commands but also part of the project.
You can store the 'whac-a-mole-kubernetes' directory anywhere you like, as long as you set the correct MINIKUBE_HOME location for each terminal session

export MINIKUBE_HOME=~/PycharmProjects/whac-a-mole-kubernetes;
export PATH=$MINIKUBE_HOME/bin:$PATH
export KUBECONFIG=$MINIKUBE_HOME/.kube/config
export KUBE_EDITOR="code -w"

To create a new minikube profile

In our application we use the profile 'whac'. This profile can be created in the following way:

minikube --profile whac config set memory 6144
minikube --profile whac config set cpus 2
minikube --profile whac config set vm-driver hyperkit
minikube --profile whac config set kubernetes-version v1.15.6
minikube start --profile whac
minikube profile whac

How to start the molegame

After you set the terminal commands to get a working minikube setup and started the 'whac' profile, we can build the pod and relay. The assumption is made that we start from the project directory.

eval $(minikube docker-env)
cd relay
docker build -t molerelayprod . 
cd ../pod
docker build -t molepodprod . 

Once the docker images are build, we can already start out application.
This can either be done by pip installing our game, or by simply running game/src/molegame/main.py.
In the case you kept the default ports, the interface of whac-a-mole is accessible at http://localhost:80. \

How to contribute

1. Fork the repository.

2. Make your change.

3. Verify the changes are correct by running.

    mypy --ignore-missing-imports pod/src/molepod/ game/src/molegame/ relay/src/molerelay/
    flake8 --max-line-length=100 pod/src/molepod game/src/molegame relay/src/molerelay
   

4. Provide a pull request.

Special thanks to

• Burr Sutter for his excelent explanation of Kubernetes.
• The designer of this image of which I borrowed my design.