Deploying Simple Applications with Kubernetes

This project aims to provide a comprehensive guide on how to deploy simple web applications using MicroK8s, a lightweight Kubernetes distribution, focusing on two popular frameworks: Django for Python and Gin for Go. By exploring both technologies, developers can gain insights into container orchestration with Kubernetes while also understanding how to build and deploy applications in different programming environments.

Before first run

• Enable ingress addon which will add nginx ingress controller

microk8s enable ingress

• Create namespaces

microk8s kubectl apply -f ./kube/namespaces.yml

• Create all services, ingress, secret and other items

New app version deployement

1. For simplicity create variable for version

export version=v<int> name=<string:["django" | "gin"]> path=<string:["." | "./gin/."]>

2. Build image

docker build -t ${name}_web:$version ${path:-.}

3. Import image into microk8s registry

microk8s ctr image import image_tmp.tar

• Optional: verify the entry microk8s ctr images ls | rg $name

4. Edit ./kube/${name}-deployment.yml image and put the new version
5. Save local image

docker save ${name}_web:$version > image_tmp.tar

• for django Edit ./kub/nginx-deployment.yml as well

6. Apply deployment

microk8s kubectl apply -f ./kube/${name}-deployment.yml

Deployment variables for django app

• unset path
• export name=django version=v<bumped_version>

Deployment variables for gin

• export name=gin version=v<bumped_version> path=./gin/.

• note: some endpoints are supported yet, due to missing db connection.

Managing kubernetes

Run the dashboard microk8s.dashboard-proxy

Running app:

Known issue

Sometimes when pods are starting you might see django connection issues and nginx error message. To solve that issue restart pods:

kubectl rollout restart -n backend-django deployment mk8sdjango

dashboard:

Running new services

Postgres

Run microk8s kubectl apply -f ./kube/postgres-<name>.yml:

• secrets
• volume
• configmap
• deployment
• service

Change the default credentials.

What's next?

• helm documentation
• gunicorn for django app
• DB for gin app