Python flask hello-world application deployment on Kubernetes!

This is a sample Python flask hello world application to demonstrate the application containerisation and orchestration workflow.

Setup the workspace

1. Clone the repostiory locally

$ git clone --recursive [email protected]:anrajme/k8s-demo.git

Build the container and upload to the registry

1. Building docker image

$ docker build -f Dockerfile -t hello-world:v1 .

2. Tag the new image

$ docker image tag hello-world:v1 anraj/hello-world:v1

3. Push the image to Docker hub

$ docker push anraj/hello-world:v1

Create the Kubernetes objects

1. Create kubernetes Deployment

$ kubernetes create -f deployment.yaml

2. Create the Kubernetes service

$ kubernetes create -f service.yaml

Verify the application

1. Verify the hello-world application by accessing it via the Node's public IP address. Its "localhost" in case if you are using docker-desktop

$ curl http://locahost:30000

Upgrade the application and test the deployment rollout

1. Edit main.py to print "Hello world V2!"

2. Follow the above steps to build a new image and tag it as hello-world:v2

$ docker build -f Dockerfile -t hello-world:v2 .

$ docker image tag hello-world:v2 anraj/hello-world:v2

$ docker push anraj/hello-world:v2

3. Update the Docker image to rollout the new version

$ kubectl set image deployment/hello-world hello-world=anraj/hello-world:v2

4. Verify the rollout status

$ kubectl rollout history deployment/hello-world

5. Verify the new application Version

$ curl http://locahost:30000

6. Rollback the application to the previous version and verify

$ kubectl rollout undo deployment/hello-world

$ kubectl rollout status deployment/hello-world

$ curl http://locahost:30000