Developing with Docker and K8s

This demo app shows a simple user profile app set up using Docker and K8s

With Docker

Step 1: Create docker network

docker network create mongo-network 

Step 2: Start mongodb

docker run -d -p 27017:27017 -e MONGO_INITDB_ROOT_USERNAME=admin -e MONGO_INITDB_ROOT_PASSWORD=password --name mongodb --net mongo-network mongo    

Step 3: Start mongo-express

docker run -d -p 8081:8081 -e ME_CONFIG_MONGODB_ADMINUSERNAME=admin -e ME_CONFIG_MONGODB_ADMINPASSWORD=password --net mongo-network --name mongo-express -e ME_CONFIG_MONGODB_SERVER=mongodb mongo-express   

NOTE: Creating docker-network in optional. You can start both containers in a default network. In this case, just emit --net flag in docker run command

Step 4: Open mongo-express from browser

http://localhost:8081

Step 5: Create user-account db and users collection in mongo-express

Step 6: Start your nodejs application locally

cd app
npm install 
node server.js

Step 7: Access you nodejs application UI from browser

http://localhost:3000

With Docker Compose

Step 1: Start mongodb and mongo-express

docker-compose -f docker-compose.yaml up

Step 2: Open mongo-express from browser

http://localhost:8080

Step 3: Start your nodejs application locally

cd app
npm install
node server.js

Step 4: Access you nodejs application UI from browser

http://localhost:3000

Build a docker image from the application and push to DockerHub

docker build -t hoangviet2001/demo-app:latest .     
docker push hoangviet2001/demo-app:latest  

The dot "." at the end of the command denotes location of the Dockerfile.

With K8s

Step 1: Start and check status your Minikube cluster

minikube start
minikube status

Step 2: Create the ConfigMap and the Secrets

kubectl apply -f mongo-config.yaml
kubectl apply -f mongo-secret.yaml

Step 3: Create the Deployment and defining the Service

kubectl apply -f mongo.yaml
kubectl apply -f webapp.yaml

Step 4: Check the information of each component in K8s

• Check basic information of each component in K8s

    kubectl get node
    kubectl get pod
    kubectl get svc
    kubectl get all
  

• Check extended information of each component in K8s

    kubectl get pod -o wide
    kubectl get node -o wide
  

• Check details of a specific component in K8s

    kubectl describe svc {svc-name}
    kubectl describe pod {pod-name}
  

• Check the logs for a container in a pod.

    kubectl logs {pod-name}
  

Step 5: Stop your Minikube cluster

minikube stop

Step 6: Delete all of the Minikube clusters

minikube delete --all

 

⚠️ Known issue - Minikube IP not accessible

If you can't access the NodePort service webapp with MinikubeIP:NodePort, execute the following command:

minikube service webapp-service

 

Links

• webapp image on Docker Hub: https://hub.docker.com/layers/hoangviet2001/demo-app/latest/images/sha256-3b00b5fa786dc9f9846488c58c9100ad25e1f8eaa13b401e95a23cd4df3960c7?tab=layers
• mongo image on Docker Hub: https://hub.docker.com/_/mongo