Python development example using Docker and Kubernetes

This project is an example of python application development in a Kubernetes cluster which is created using vagrant and ansible in a local development environment.

Installation

• Docker - for install Docker Desktop
• Virtualbox - for install Virtualbox
• Vagrant - for install Vagrant
• kubectl - for install kubectl client

Preparing environment

Clone the git repository and install the K8s cluster using vagrant on local environment.

Run this command to clone the git repo of project

$ git clone https://github.com/koseburak/hello-py.git

Run this command to install local environment in the same directory as Vagrantfile

$ vagrant up

Copy created "config" file into the "$HOME/.kube/" folder to manage provisioned K8s cluster

$ cp devops/ansible-playbooks/config ~/.kube/config

Development and Deployment

1. Development

1.1. Make changes on your python application in local repository.

2. Build docker image

Run this command to define the private docker registry address as a env variable on your local environment

$ export $REGISTRY="192.168.50.10:30001"

2.1. Build new docker image for the developed code of application ( run this command in the same directory as Dockerfile )

$ docker build -t $REGISTRY/hello-py:0.0.1 .

2.2. Push the new docker image of your application to private docker registry running on the local k8s cluster

$ docker push $REGISTRY/hello-py:0.0.1

3. Deployment

Deploy the new version of application to K8s cluster.

3.1. If you are deploying your application for the first time, run this command

$ kubectl apply -f devops/k8s/hello-py-deployment.yaml

3.2. After each new development you make, you have to create a new docker image with new version tag ( by running commands in the 2.step ) and update the K8s deployment file in a way that it uses the new docker image with the following command

$ kubectl set image deployment/hello-py hello-py=127.0.0.1:30001/hello-py:0.0.2

3.3. Check of your deployment and pods if they are is ready

$ kubectl get deploy -n default

$ kubectl get pods -n default

3.4. Now, try to access your application via the browser using the address below

http://192.168.50.10:30100/